opinion: Mr. Justice Brennan
  delivered the opinion of the-Court.
  Section 792 of California’s Agricultural Code, which gauges the maturity of avocados by oil content, prohibits the transportation or sale in California of avocados which contain “less than 8 per cent of oil, by weight . . . excluding the skin and seed.” In contrast, federal marketing orders approved by the Secretary of Agriculture gauge the maturity of avocados grown in Florida by standards which attribute no significance to oil content. This case presents the question of the constitutionality of the California statute insofar as it may be applied to exclude from California markets certain Florida avocados which, although certified to be mature under the federal regulations, do not uniformly meet the California requirement of 8% of oil.
  Appellants in No. 45, growers and handlers of avocados in Florida, brought this action in the District Court for the Northern District of California to enjoin the enforcement of § 792 against Florida avocados certified as mature under the federal regulations. Appellants challenged the constitutionality of the-statute on three grounds : (1) that •under the Supremacy Clause, Art. VI, the California standard must be deemed displaced by the federal stand-' ard for determining the maturity of avocados grown in Florida; (2) that the application of the California statute to Florida-grown avocados denied appellants the Equal Protection of the Laws in violation of the Fourteenth Amendment; (3) that its application unreasonably burdened or discriminated against interstate marketing o.f Florida-grown avocados in violation of the Commerce Clause, Art. I, § 8. A three-judge District Court initially dismissed the complaint. 169 F. Supp. 774. On direct appeal we held, Florida Lime & Avocado Growers, Inc., v. Jacobsen, 362 U. S. 73, that the suit was one for a three-judge court under 28 U. S. C. § 2281, and presented a jus-ticiable controversy to be tried on the merits. After a trial the three-judge court denied an injunction against the enforcement of § 792, on the ground that the proofs did not establish that its’application to Florida-grown avocados violated any provision of the Federal Constitution. 197 F. Supp. 780. The District Court held for several reasons that the Supremacy Clause did not operate to displace § 792: no actual conflict existed between the statute and the federal marketing orders; neither the Agricultural Act nor the marketing orders occupied the field to the exclusion of the state statute; and Congress had • not ordained that a federal marketing order was to give a license to Florida producers to “market their avocados without further inspection by the states” after compliance with the federal maturity test. 197 F. Supp:, at 787. Rather, the court observed, “[t]he Federal law does not cover the whole field of interstate shipment of avocados” but by necessary implication leaves .the regulation of certain aspects of distribution to the States. Further, the District Court found no violation of the Equal Protection Clause because the California statute was applicable on identical terms to Florida and California producers, and was reasonably designed to enforce a traditional and legitimate interest of the State of'California in the protection of California consumers.’ The District Court concluded, finally, that § 792 did not unreasonably burden or discriminate against interstate commerce in out-of-state avocados — that the 8% oil content test served in practice only to keep off California grocers’ shelves fruit which was unpalatable because prematurely picked. This holding rested in part on the conclusion that mature Florida fruit had not been shown to be incapable of.attaining 8% oil content, since only a very small fraction of Florida avocados of certain varieties in fact failed to meet the California test.
  Both parties have brought appeals here from the District Court’s judgment: the Florida growers urge in No. 45 that the court erred in not enjoining enforcement of the state statute against Florida-grown avocados; in No. 49 the California state officials appeal on the ground that the action should have been dismissed for want of equity jurisdiction rather than upon the merits. We noted probable jurisdiction' of both appeals. 368 U. S. '964, -965. We . affirm the judgment in the respect challenged by the cross-appeal in No. 49. In No. 45 we agree that appellants have not sustained their challenges to § 792 under the Supremacy and Equal Protection Clauses. However, we reverse and remand for a new trial insofar-as the judgment sustains § 792 against appellants’ challénge to the statute grounded on the Commerce Clause. We hold that the. effect of the statute upon interstate commerce cannot be determined on the record now before us.
  The California statute was enacted in 1925. Like the federal marketing regulations applicable to appellants, this statute sought to ensure the maturity of avocados reaching retail markets. The District Court found on sufficient evidence that before 1925 the marketing of immature avocados had created serious problems in California. An avocado, if picked prematurely, will not ripen properly, but will tend to decay or shrivel and become rubbery and unpalatable after purchase. Not only retail consumers but even experienced grocers have difficulty in distinguishing mature avocados from the immature by physical characteristics alone. Thus, the District Court concluded, “[t]he marketing of . . . [immature] avocados cheats the consumer” and adversely affects demand for and orderly distribution of the fruit. 197 F. Supp., at 783.
  The federal marketing regulations were adopted pursuant to the Agricultural Adjustment Act, 7 U. S. C. §§ 601 et seg. The declared purposes of the Act are to restore and maintain parity prices" for the benefit of producers of agricultural commodities, to ensure the stable' and steady flow of commodities to consumers, and “to establish and maintain such minimum standards of quality and maturity ... as will effectuate such orderly marketing of such agricultural commodities as will be in the public interest,” § 2 (3), 7 U. S. C. § 602 (3). Whenever he finds that it would promote these declared policies, the Secretary is empowered upon notice and hearing to adopt federal marketing orders and regulations for a particular growing area, § 8c (3), (4),'7 U. S. C. § 608c (3), (4). Orders thus proposed by the Secretary become effective only when approved by a majority of the growers or producers concerned, § 8c (8), (9), 7 U. S. C. § 608c (8), (9).
  In 1954, after proceedings in compliance with the statute, 19 Fed. Reg. 3439, the Secretary promulgated orders governing the marketing, of avocados grown in South Florida. The orders established an Avocado Administrative Committee, composed entirely of South Florida avocado growers and handlers. 7 CFR § 969.20. This Committee has authority to draft and recommend to the Secretary various marketing regulations governing the quality and maturity of South Florida avocados. The maturity test for the South Fbrida fruit is based upon a schedule of picking dates, sizes and weights annually drafted and recommended by the Committee and promul-gáted by the Secretary. The regulations forbid picking and shipping of any fruit before the prescribed date, although an exemption from the picking-date schedule may be granted by the Committee. The regulations drafted by the Committee and promulgated by the Secretary concern other qualities and physical characteristics of Florida avocados besides maturity. See 22 Fed. Reg. 6205, 7 CFR §§ 51.3050-51.3053, 51.3064. All regulated avocados, including those shipped under picking-date exemptions, must be inspected for compliance with certain quality standards by the Federal-State Inspection Service, a joint authority supervised by'the United States and Florida Departments of Agriculture.
  Almost all avocados commercially grown in the United States come either from Southern California or South Florida. The California-grown varieties are chiefly of 'Mexican ancestry, and in most years contain at least 8% oil content when mature. The several Florida species, by contrast, are of West Indian and Guatemalan ancestry. West Indian avocados, which constitute some 12% of the total Florida production, may contain somewhat less than 8% oil when mature and ready for market. They do not, the District Court found, attain that percentage of oil “until they are‘past their-prime.” 197 F. Supp., at 783. But that variety neéd not concern us in this case, since the District Court concluded on sufficient evidence that “poor shipping qualities and short retail store shelf-life” make it commercially unprofitable, regardless of the oil test, to market the variety in California. On the other hand, the Florida hybrid and Guatemalan varieties, which do not encounter such handicaps, may reach maturity before, they attain 8% oil content. The District Court concluded, nevertheless, that § 792 did not unreasonably interfere with their marketability' since these'species “attain or exceed 8% oil content while in a prime commercial marketing condition,” so that the California test was “scientifically valid as applied to” these varieties.
  The experts who testified at the trial disputed whether California’s percentage-of-oil test or the federal marketing orders’ test of picking dates and minimum sizes and weights was the more accurate gauge of the maturity of avocados. In adopting' his calendar test of maturity for the varieties grown in South Florida the Secretary expressly rejected physical and chemical tests as insufficiently reliable guides for gauging the maturity of the Florida fruit.
  I.
  We consider first appellants’ challenge to § 792 under the Supremacy Clause. That the California statute and the federal marketing orders embody different maturity tests is clear. However, this difference poses, rather than disposes of the problem before us. Whether a State may constitutionally reject commodities which a federal authority has certified to be marketable depends upon whether the state regulation “stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress,” Hines v. Davidowitz, 312 U. S. 52, 67. By that test, we hold that § 792 is not such an obstacle; there is neither such actual conflict between the two schemes of regulation that both cannot stand in the same area, nor evidence of a congressional design, to preempt the field.
  We begin by putting .aside two suggestions of the appellants which obscure more' than aid in the solution of the problem. First, it is suggested that a federal license or certificate of compliance with minimum federal standards immunizes the licensed commerce from inconsistent or more demanding. state regulations. While this suggestion draws some support from decisions, which have invalidated direct state interference with the activities of interstate carriers, Castle v. Hayes Freight Lines, Inc., 348 U. S. 61, even in that field of paramount federal concern the suggestion has been significantly qualified, e. g., Huron Portland Cement Co. v. Detroit, 362 U. S. 440, 447-448; Kelly v. Washington, 302 U. S. 1; cf. Bradley v. Public Utilities Comm’n, 289 U. S. 92. That no State may completely exclude federally licensed commerce is indisputable, but that principle has no application to this case.
  Second, it is suggested that the coexistence of federal and state regulatory legislation should depend upon whether the purposes of the two laws are parallel or divergent. This Court has, on the one hand, sustained state statutes having objectives virtually identical to those of federal regulations, California v. Zook, 336 U. S. 725, 730-731; cf. De Veau v. Braisted, 363 U. S. 144, 156-157; Parker v. Brown, 317 U. S. 341; and has, on the other hand, struck down state statutes where the respective purposes were quite dissimilar, First Iowa Hydro-Electric Cooperative v. Federal Power Comm’n, 328 U. S. 152. The test of whether both federal and state regulations may operate, or the state regulation must give way, is whether both regulations c'an be enforced without impairing the federal superintendence of the field, not whether they are aimed at similar or different objectives.
  The principle to be derived from our decisions is úhat federal regulation of á field of commerce should not be deemed preemptive of state regulatory power in the absence of persuasive reasons — either that the nature of the regulated subject matter permits no other conclusion, or, that the Congress has unmistakably so ordained. See, e. g., Huron Portland Cement Co. v. Detroit, supra.
  A.
  A holding of federal exclusion of state law is inescapable and requires no inquiry .into congressional design where compliance with both federal and state regulations is a physical impossibility for one engaged in interstate commerce, cf. Union Bridge Co. v. United States, 204 U. S. 364, 399-401; Morgan v. Virginia, 328 U. S. 373; Bibb v. Navajo Freight Lines, Inc., 359 U. S. 520. That would be the situation here if, for example, the federal orders forbade the picking and marketing of any avocado testing more than 7% oil, while the California test excluded from the State any avocado measuring less than 8% oil content. No such impossibility of dual compliance is presented on this record, however. As to those Florida avocados of the hybrid and Guatemalan varieties which were actually rejected by-the California test, the District Court indicated-that the Florida growers might have avoided such rejections by leaving the fruit on the trees beyond the earliest picking date permitted by the federal regulations, and nothing in the record contradicts that suggestion. -Nor is there a lack of evidentiary support for the District Court’s finding that the Florida varieties marketed in California “attain or exceed 8% oil content while in a prime, commercial marketing condition,” even though they may be “mature enough to be acceptable prior to the time that they reach that content . . . .” 197 F. Supp., at 783. Thus the present record demonstrates no inevitable collision between the two schemes of regulation, despite the dissimilarity of the standards.
  B.
  The' issue under the head of the Supremacy Clause is narrowed then to this: Does either the nature of the subject -matter, namely the maturity of avocados, or any explicit declaration of congressional design to displace state regulation, require' § '792 to yield to the federal marketing orders? The maturity of avocados seems to be an inherently unlikely candidate for exclusive federal regulation. Certainly .it is not a subject by its very nature admitting only of national supervision, cf. Cooley v. Board of Port Wardens, 12 How. 299, 319-320. Nor is it a subject demanding exclusive federal regulation in order to achieve uniformity vital to national interests, cf. San Diego Building Trades Council v. Garmon, 359 U. S. 236, 241-244.
  On the contrary, the maturity of avocados is a subject matter of the kind this Court has traditionally regarded as properly within the scope of state superintendence. Specifically, the supervision of the readying of foodstuffs for market has always been deemed a matter of peculiarly local concern. Many decades ago, for example, this Court sustained a State’s prohibition against the imp'ortation of artificially colored oleomargarine (which posed no health problem), over claims of federal preemption and burden-on commerce. In the course of the opinion, the Court recognized that the States have always possessed a legitimate interest in “the protection of . . . [their] people against fraud and deception in the sale of food products” at retail markets within their borders. Plumley v. Massachusetts, 155 U. S. 461, 472. See also Crossman v. Lurman, 192 U. S. 189, 199-200; Hygrade Provision Co. v. Sherman, 266 U. S. 497; Savage v. Jones, 225 U. S. 501, 525-529.
  It is true that more recently we sustained, a federal statute broadly regulating the production of renovated butter. But we were scrupulous in pointing out that a State might nevertheless — at least in the absence of an express contrary command of Congress — confiscate or exclude from market the processed butter which had complied with all the federal processing standards, “because of a higher standard demanded by a state for its consumers.” A state regulation so purposed was, we affirmed, “permissible under all the authorities.” Cloverleaf Butter Co. v. Patterson, 315 U. S. 148, 162. That distinction is a fundamental one, which illumines and delineates the problem of the present case. Federal regulation by means of minimum standards of the picking, processing, and transportation of agricultural commodities,, however comprehensive for those purposes that regulation may be, does not of itself import displacement, of state control over the distribution and retail sale of those commodities in the interests of the consumers of the commodities within the State. Thus, while Florida may perhaps not prevent the exportation of federally certified fruit by‘superimposing a higher maturity standard, nothing in Cloverleaf forbids California to regulate their marketing. Congressional regulation of one end of the stream of commerce does not, ipso facto, oust all state regulation at the other end. Such a displacement may not be inferred automatically from the fact that Congress has regulated production and packing of commodities for the interstate market. We do not mean to suggest that certain local regulations may not unreasonably or arbitrarily burden interstate commerce; we consider that question separately, infra, pp. 152-154. Here we are concerned only whether partial congressional superintendence of the field (maturity for the purpose of introduction of Florida fruit into the stream of interstate commerce) automatically forecloses regulation of maturity by another State in the interests of. that State’s' consumers of the fruit.
  The .correctness of the District Court’s conclusion that § 792 was a regulation well within the scope of California’s police powers is thus clear. While it is conceded that the California statute is not a health measure, neither logic nor precedent invites ány distinction.between state regulations designed to keep unhealthful or unsafe commodities off the grocer’s shelves, and those designed to prevent the deception of consumers. See, e. g., Hygrade Provision Co. v. Sherman, supra; Plumley v. Massachusetts, supra. Nothing appearing in the record before us affords any ground for departure in this case from our consistent refusal to draw such a distinction.
  c.
  Since no irreconcilable conflict with the federal regulation requires a conclusion that § 792 was displaced, we turn to the question whether Congress has nevertheless ordained that the state regulation shall yield. The settled mandate governing this inquiry, in deference to the fact that a state regulation of this kind is an exercise of the “historic police powers of the States,” is not to decree such a federal displacement “unless that was the clear and manifest purpose of Congress,” Rice v. Santa Fe Elevator Corp., 331 U. S. 218, 230. In other words, we are not to conclude that Congress legislated the ouster of this California statute by the marketing orders in the absence of an unambiguous congressional mandate to that effect. We search in vain for such a mandate.
  The provisions and objectives of the Agricultural Adjustment Act bear little resemblance to those in which only last Term we found a preemptive design in Campbell v. Hussey, 368 U. S. 297. In the Federal Tobacco Inspection Act involved in that case, Congress had declared “uniform standards of classification and inspection” to be “imperative for the protection of producers and others engaged in commerce and the public interest therein.” 7 U. S. C. § ,511a. The legislative history was replete with references to a need for “uniform” or “official” standards, which could harmonize the grading and inspection of tobacco at all markets throughout the country. Under the. statute-a single set of standards was to be promulgated by .the Secretary of Agriculture, “and the standards so established would be the official standards of the United States for such purpose.” S. Rep. No. 1211, 74th Cong., 1st Sess. 1.
  Nothing in the language of the Agricultural Adjustment ■ Act — passed by the same Congress the very next day— discloses a similarly comprehensive congressional design. There is but one provision of the statute which intimates any purpose to make agricultural production controls thé monitors of retail distribution — the reference to a policy of establishing such “minimum standards of quality and maturity and such grading and inspection requirements ... as will effectuate . . . orderly marketing . . . in the public interest.” 7 U. S. C. § 602 (3). That language cannot be said, without more, to reveal a design ' that federal marketing orders should displace all state regulations. By its very terms, in fact, the statute purports only to establish minimum standards.
  Other provisions of the Act, and their history, militate even more strongly against federal displacement of these state regulations. • First, the adoption of marketing agreements and orders is authorized only when the Secretary has determined that economic conditions within a particular growing area require federally supervised cooperation among the growers to alleviate those conditions. 7 U. S. C. § 608c (1), (2). Moreover, the relief afforded the growers is to be temporary; “the Secretary is directed to cease exercising such powers” when “the circumstances described ... no longer exist.” H. R. Rep. No. 1241, 74th Cong., 1st Sess. 4. . And consistently with' these terms, the Secretary himself has characterized the marketing agreements as essentially “self-help programs” instituted and administered by the farmers involved. This view has recently been elaborated by the Secretary:
  “The Act itself does not impose regulations over the marketing of any agricultural commodity. It merely provides the authority under which an industry can develop regulations to fit its own situation and solve its own marketing problems.” United States Department of Agriculture, Marketing Agreements and Orders, AMS-230 (rev. ed. 1961), 3. See also United States Department of Agriculture, Agricultural Adjustment 1937-1938 (1939), 71.
  Second, the very terms of the statute require that the Secretary promulgate marketing orders “limited in their application to the smallest regional production areas” which he finds practicable; and the orders are.to “prescribe such different terms, applicable to different production areas and' marketing areas” as will serve to “give due recognition to the . differences in production, and marketing” between those areas. 7 U. S. C. § ,608c (11). While this language is not conclusive on the question before us, it indicates that Congress contemplated — quite by contrast to the design embodied in the Tobacco Inspection Act — that there might be widespread regional variations in the standards governing production and processing. Thus avocado growers in another region could, for example, propose — and the Secretary would presumably adopt — maturity regulations which would gauge the marketability of the fruit not by the calendar, as do the South Florida rules, but by the color of the skin, or the texture and color of the seed-coat, or perhaps even by oil content. Thus if the Congress of 1935 really intended that distribution would be comprehensively governed by grower-adopted quality and maturity standards, and all state regulation of the same subject would be ousted, it does not seeni likely that the statute would have invited local variations at the production end while saying absolutely nothing about the effect of those production controls upon distribution for consumption.
  A third factor which strongly suggests that Congress did not mandate uniformity for each marketing, order arises from the legislative history. The provisions concerning the limited duration and local application of marketing agreements received much attention from both House and Senate Committees reporting on the bill. Though recognizing that the powers conferred upon the Secretary were novel and extensive, both Committees concluded : “These and other restrictive provisions are... adequately drawn to guard against any fear that the regulatory power is so broad as to subject its exercise to the risk of abuse.” H. R. Rep. No. 1241, 74th Cong., 1st Sess. 7; S. Rep. No. 1011, 74th Cong., 1st Sess. 3. The Committee Reports also discussed § 10 (i), 7 U. S. C. §610(i), which authorized federal-state cooperation in the administration of the program, and cautioned significantly: '
  “Notwithstanding the authorization of cooperation contained in this section, there is nothing in it to permit or require the Federal Government to invade the field of the States, for the limitations of the act and the Constitution forbid federal regulation in that field, and this provision does not indicate the contrary. Nor is there, anything in the provision to force States to cooperate. Each sovereignty operates in its own sphere but can exert its authority in conformity rather than in conflict with that of the other.” H. R. Rep. No. 1241, 74th Cong., 1st Sess. 22-23; S. Rep. No. 1011, 74th Cong., 1st Sess. 15.
  Thus the revealed congressional design was apparently to do no more than to invite farmers and growers to get together, under the auspices of the Department of Agriculture, to work out local harvesting, packing and processing programs and thereby relieve temporarily depressed marketing conditions. Had Congress meant the Act to have in addition a pervasive effect upon the ultimate distribution and sale of produce, evidence of such a design would presumably have accompanied the statute, as it did the Tobacco Inspection Act, see Campbell v. Hussey, supra. In the absence of any such manifestations, it would be unreasonable to infer that Congress delegated to the growers in a particular region the authority to deprive the States of their traditional power to enforce otherwise valid regulations designed for the protection of consumers.
  An examination of the operation of these particular marketing orders reinforces the conclusion we reach from this analysis of the terms and objectives of the statute. The regulations show that the Florida avocado maturity standards are drafted each year not by impartial experts in Washington or even in Florida, but rather by the South Florida Avocado Administrative Committee, which consists entirely of representatives of the growers, and handlers concerned. It appears that the Secretary of Agriculture has invariably adopted the Committee’s recommendations for maturity dates, sizes, and weights. Thus the pattern which emerges is one of maturity regulations drafted and administered locally by the growers’ own representatives, and designed to do no more than promote orderly competition among the South Florida growers;
  This case requires no consideration of the scope of the constitutional power of Congress to oust all state regulation of maturity, and we intimate no view upon that question. It is. enough to decide this aspect of the present case that wé conclude that Congress has not attempted to oust or displace state powers to enact the regulation embodied in § 792. The most plausible inference from the legislative scheme is that the Congress contemplated that state power to enact such regulations should - remain unimpaired.
  II.
  We turn now to appellants’ arguments under the Equal Protection and Commerce Clauses.
  It is enough to dispose of the equal protection claim that we express our agreement with the District Court that the state standard does not work an “irrational discrimination as between persons or groups of persons,” Goesaert v. Cleary, 335 U. S. 464, 466; cf. Railway Express Agency, Inc., v. New York, 336 U. S. 106. While it may well be that arguably superior tests of maturity could be devised, we cannot say, in derogation of the findings of the 'District Court, that this possibility renders the choice made by California either arbitrary or devoid of rational relationship to a legitimate regulatory interest. Whether or not the oil content test is the most reliable indicator of marketability of avocados- is not a question for the courts to decide; it is sufficient that on this record we should .conclude, as we.do, that oil content appears to be an acceptable criterion of avocado maturity.
  More difficult is the claim that the California statute unreasonably burdens or discriminates against interstate commerce because its application has excluded Florida avocados from the State. Although Florida and California were competitors in avocado production when the statute was passed in 1925, the present record permits no inference that the California statute had a discriminatory .objective. Nevertheless it may be that the continued application of this regulation to Florida avocados has imposed an unconstitutional burden on commerce, or has discriminated against another State’s exports of. the particular commodity. Other state regulations raising similar problems have been found to be discriminatory or burdensome notwithstánding a legitimate state interest in some form of regulation — either because they exceeded the limits necessary to vindicate that interest, Dean Milk Co. v. Madison, 340 U. S. 349, or because they unreasonably favored local producers at the expense of competitors from other States, Baldwin v. Seelig, Inc., 294 U. S. 511. Such a state regulation might also constitute án illegitimate attempt to control the conduct of producers beyond the borders of California, cf. Bibb v. Navajo Freight Lines, Inc., supra; Southern Pacific Co. v. Arizona, 325 U. S. 761, 775.
  The District Court referred to these precedents but nevertheless concluded that the California oil content test-was not burdensome upon or discriminatory against interstate commerce. 197 F. Supp., at 786-787. However, we are unable to review that conclusion or decide whether the court properly applied the principles announced in these decisions because we cannot ascertain what constituted the record on which .the conclusion was predicated. Much of the appellants’ offered proof consisted of depositions and exhibits, designed to detail both the rejection of Florida avocados in California and the oil content of Florida avocados which had met the federal test but which might nonetheless have been excluded from California markets.
  The parties’ own assumptions concerning the content of the record are in irreconcilable conflict: the appellants have argued the case on the apparent assumption, that the depositions and exhibits ivere admitted before the District Court; the appellees, on the' other hand, have assumed both in their briefs and in oral, argument that the disputed evidence was not admitted. This lack of consensus is altogether understandable in light of the confusion created by the District Court’s evidentiary rulings; The appellees objected to the introduction of the disputed materials on several grounds, both during and after the trial. The court expressly reserved its rulings on the issue .of admissibility, and after the entry of its order on the merits of the case made, a supplemental “ruling on évidentiary matters,” in which .it stated that the disputed exhibits and depositions “aré not admitted into evidence, but have been considered by the Court as an offer of proof by the plaintiffs . . . .” The earlier memorandum of the court explained that it would “assume, arguendo, that the exhibits and depositions offered by plaintiffs are all admissible.” 197 F. Supp., at 782. If this was intended to mean that appellants would not have made out a case for relief, even were the evidence to be admitted, then there would have been no need to rule on admissibility. But we are unable to determine, just as the parties were unable to agree, whether the District Court viewed the evidence in'that posture.
  Thus the only evidence which would seem to support an injunction on. the ground of burden on interstate commerce has never been formally admitted to the record in this case. For this Court to reverse and order an injunction on the basis of that evidence would be, in effect, to admit the contested depositions and exhibits on appeal without ever affording the appellees an opportunity to argue their seemingly substantial objections. To assume the admissibility of the evidence under these circumstances would be to deny the appellees their day in court as to. a disputed part of the case on which the trial court has never ruled because its view of the law evidently made such -a ruling unnecessary. Cf. Byrd v. Blue Ridge Rural Electric Cooperative, Inc., 356 U. S. 525, 533; Fountain v. Filson, 336 U. S. 681; Globe Liquor Co. v. San Roman, 332 U. S. 571. On the other hand, to affirm the District Court would require us to make equally impermissible assumptions as to the state of the record. Cf. Florida v. United States, 282 U. S. 194, 215.
  For these reasons we conclude that the judgment must, to the extent appealed from in No. 45, be reversed and the case remanded to the District Court for a new trial of appellants’ Commerce Clause contentions. We intimate no view with respect to either the admissibility or the probative value of the disputed evidence, or of any other evidence which might be brought forth by either party concerning this aspect of the case.
  III.
  In No. 49, the state officers cross-appeal on the ground that the District Court should have dismissed the action for want of equity, rather than for lack of merit. Their contention is that there was insufficient showing of injury to the Florida growers to invoke the District Court’s equity jurisdiction: We ■ reject that contention, and affirm the judgment insofar as it is challenged by the cross-appeal.
  In Florida Lime & Avocado Growers, Inc., v. Jacobsen, 362 U. S. 73, we held that because of the Florida growers’ allegations that California officials had consistently condemned Florida avocados as unfit for sale in California, “thus requiring appellants [the Florida growers] — to prevent destruction and complete loss of their shipments — to reship the avocados to and sell them in other States,” it was evident that “there is an existing dispute between the parties as to present legal rights amounting to a justiciable controversy which appellants are entitled to have determined on the merits.” 362 U. S., at 85-86. In viéw of our mandate in Jacobsen, therefore, the District Court necessarily assumed jurisdiction and heard the case on its merits. Cf. United States v. Haley, 371 U. S. 18.
  Even on the present ambiguous record, we think that the Florida growers have demonstrated sufficient injury to warrant at least a trial of their allegations. In the California officials’ briefs below, it was conceded that the Florida growers had suffered damage in the amount of some $1,500 by reason of the enforcement of the statute. Before the bar of this Court, it was conceded that the State, in objecting to the growers’ proffered evidence, did not dispute the claim that some shipments of Florida avocados had in fact been rejected by California for failure to comply with the oil content requirement. Indeed, the State conceded in its pleadings before the trial court that rejections of Florida avocados had averaged in recent years as much as 6.4% of the total shipments of Florida fruit into California. While these concessions were not corroborated by statistical’proofs at trial, and thus do not form an adequate basis for the entry of a final injunction, they nevertheless supplied an adequate basis,'apart from the requirement of our remand, for the District Court’s proceeding to trial on the merits.
  In addition, it is clear that the California officials will continue to enforce the statute against the Florida-grown avocados, for the State’s answer to the complaint declared that these officials “have in the past and now stand ready to perform their duties under their oath of office should they acquire knowledge of violations of the Agricultural Code of the State of California.” Thus the District Court, both on the pleadings before it, and in light of our opinion in Jacobsen, properly heard the remanded case on the merits and did not err in refusing to dismiss for want of equity jurisdiction.
  The cross-appellants rely upon the court’s finding of fact that “[p]laintiffs have neither suffered nor been threatened with irreparable injury.” This finding was, however, adopted pursuant to that court’s prior opinion, which stated that “[p] lain tiffs’ monetary losses as a result of the rejected shipments are not clearly established, but at most do not appear to be oyer two or three thousand dollars.” 197 F: Supp., at 783-784. We read this finding as importing no more than the District Court’s view that whatever harm or damage the Florida growers might have suffered fell short of the “irreparable injury” requisite for the entry of an injunction against enforcement of the statute.
  The judgment of the District Court is reversed and the cause is remanded for a new trial limited to appellants’ claim in No. 45 that the enforcement of § 792 unreasonably burdens or discriminates against interstate commerce. In the respect challenged by the cross-appeal in No. 49, the judgment i's affirmed
  It is so ordered.
  Avocados not meeting this standard may not be sold in California. Id.. § 784. Substandard fruits are “declared to be a public nuisance,” and they may be seized, condemned, and abated. Id., § 785. Violators may be punished criminally, id., § 831 ($50 to $500 fine or imprisonment for not more than six months, or both), and by civil penalty action, id., § 785.6 (market value of fruits).
  The orders are approyed by the Secretary pursuant to § 8c of the Agricultural Adjustment Act, 7 U. S, C. § 608c. The basic marketing agreement provisions were initially adopted, in substantially their present form, in the 1935 amendments to the Agricultural Adjustment Act, 49 Stat. 750, 753-761. These sections were, reenacted in 1937, 50 Stat. 246, as the Agricultural Marketing Agreement Act of 1937, virtually unchanged. Concerning the reasons for the reenactment, and the extent of the changes, see United States Department of Agriculture, Agricultural Adjustment 1937-1938 (1939), 72-73. •
  The evidence in the record concerning the actual effect of the California maturity test upon Florida avocados is sketchy at best. The appellants introduced only one witness, a marketing expert in the United States Department of Agriculture, who testified concerning the relative scientific and other merits of the federal and California maturity tests. He gave no testimony concerning the actual impact of the California regulation upon shipments from Florida. One of appellees’ witnesses at trial made cursory references to the fact that California inspectors had rejected and excluded some Florida shipments, but there was no testimbny concerning the dates and quantities of any rejections. In a motion for dismissal and an accompanying affidavit before the District Court, the appellees presented certain figures concerning^ the percentage of Florida avocados which failed to comply with the Cálifornia regulation during the years 1954 through 1957. There was, however, neither data for years after 1957 nor statistical proof at the trial which would corroborate these summary figures.
  See Roche, Regulations for Marketing Avocados, in California, in California Avocado Assn. 1937 Yearbook (1937), 88-89, concerning the purpose of the California oil-test statute. It has not been contended that the purpose of this statute is to ensure a certain caloric or nutritional value in avocados which reach the consumer. No health issue has been raised in this case. See 197 F. Supp., at 785-786.
  See also Church and Chace, Some Changes in the Composition of California Avocados During Growth (U. S. Dept, of Agriculture Bull. No. 1073, 1922), -2; Hodgson, The California Avocado Industry (Calif. Agricultural Extension Service Circular No. 43, 1930), 54-55; Hodges, Immature Avocado Selling Illegal, 111 Pacific Rural Press, Apr; 3, 1926, p. 435. And for a discussion of the particular problems encountered in the marketing of immature avocados in California, see Roche, supra, note 4, at 88-89.
  The nature of the avocado and its ripening process make it very difficult for ariy but the expert to gauge its maturity, and an avocado which may appear satisfactory at the time of purchase may later fail to ripen properly because it was prematurely picked. See, e. g., Ruehle, The Florida Avocado Industry (Univ. of Fla. Agr. Expt. Stations Bull. No. 602, 1958), 69; Avocado Maturity Tests, 37 California Citrograph, Dec. 1951, p. 87; Roche, Look Out for Immature Avocados, 87 California Cultivator, Nov. 2, 1940, p. 590; Church and Chace,, supra, note 5, at 2.
  This order is applicable only to avocados grown in the South Florida growing area. The California growers have not adopted a federal marketing order or agreement.
  The findings of the United States Department of Agriculture, contained in its order determining what terms should be contained in the avocado regulations, were that the marketing of immature fruits increases consumer resistance and materially impairs the marketing of the entire crop, that there was no satisfactory physical or chemical test for determining maturity, and that maturity can satisfactorily be determined by the picking-date-size method. Handling of Avocados Grown in South Florida, 19 Fed. Reg. 2418, 2424-2425.
  Each year since 1954, the Secretary has issued maturity regulations fixing the dates upon which each variety of Florida avocados may be picked and shipped. See, e. g., 27 Fed. Reg. 5135-5136, 6705, 8264-8265, 9174-9175, 10090-10091.
  Section .53 of the regulations, 7 CFR § 969.53, provides that an exemption certificate shall be granted to a grower “who furnishes, proof, satisfactory to the committee, that his avocados of a particular variety are mature prior to the time such variety may be handled under such regulation.” Such a certificate authorizes the recipient to “handle” the certified fruit, i. e., to “sell, consign, deliver, or transport avocados within the production area or between the production area and any point outside thereof 7 CFR § 969.10.
  See Traub et al., Avocado Production in the United States (U. S. Dept, of Agriculture Circular' No. 620, 1941), 6-8. Occasionally, however, even California growers have experienced difficulty in meeting the oil content requirement, and sizable shipments have had to be destroyed. See Demand for Avocados, 74 California Cultivator, Feb. 8, 1930, p. 167; Roche, Look Out for Immature Avocados, 87 California Cultivator, Nov. 2, 1940, p. 590; California Avocado Assn. 1937 Yearbook (1937), 88.
  Compare Hodgson, The California Avocado Industry (Calif. Agricultural Extensityi Service Circular No. 43, 1930), 39.
  See 19 Fed. Reg. 2418, 2424-2425; compare Harding, The Relation of.Maturity to Quality in Florida Avocados, 67 Florida State Horticultural Society Proceedings, 276 (1954).
  It is true that the statute involved in the Cloverleaf case provided that federal law was not intended to displace state laws “enacted in the exercise of [the States’] -police powers . . . .” 32 Stat. 193, 21 U. S. C. § 25. But this proviso was presumably intended to do no more than recognize explicitly an accommodation between' federal and state interests to which Congress and the decisions of this Court have, consistently adhered. Nor did the Court’s deference to state regulation rest upon this congressional proviso. Rather, the Court simply considered it a well-settled proposition that a State may impose upon imported foodstuifs “a higher standard demanded . . . for its consumers.”
  It might also b.e argued that the California statute, having been designed-to test the maturity only of California avocados, bears no rational relationship to. the marketability of Florida fruit. Such a contention would seem untenable, however, in the face of the District • Court’s express finding of fact, supportable on the testimony before it, that “[a-] standard requiring a minimum of 8% of oil in an avocado before it may be marketed is scientifically valid as applied to hybrid and Guatemalan varieties of avocados grown in Florida and marketed in California.” And there is considerable dispute as to the oil conten’ of Florida avocados which have been certified as mature under th 'federal regulations. See note 21, infra.
  The marketing agreement provisions were enacted among the 1935 amendments to the Agricultural Adjustment Act, 49 Stat. 750753-761. These amendments were accepted by Congress the day following the enactment of the Tobacco Inspection Act, 49 Stat. 731-735.
  Although the Manager of the Avocado Administrative Committee stated in his deposition (which was neither formally admitted nor excluded by the District Court) that the Secretary had occasionally rejected orders recommended by the Committee, he insisted that as to maturity regulations “the Secretary has always followed the Committee’s recommendations.” •
  Significant with regard to the essentially local nature of the orders and their administration is the testimony in a deposition (on the admissibility of which the District Court did not rule) .of the supervising inspector of fruits and vegetables of the Federal and State Agricultural Inspection Service for the South Florida district: •
  “. . . these regulations ■ from time to time are subject to change at the direction of the Avocado Administrative Committee. Whenever they do change them, Mr. Biggar, the manager of the Avocado Administrative Committee, immediately furnishes the inspection service with copies of the effective rules and changes. There are times when they change them, and when they change them I am the first man to get the changed regulations, because I have to see that the inspectors get the revised regulations issued by the Avocado Administrate vm Committee.” "
  For further evidence that the avocado marketing agreement was undertaken chiefly as a “self-help program,” designed only to regulate South Florida production and ensure maturity of the produce from that growing area, see Krome, The Federal Avocado Marketing Agreement, 67 Florida State Horticultural Society Proceedings 268 (1954).
  Compare, e. g., Oregon-Washington B. & Nav. Co. v. Washington, 270 U. S. 87; McDermott v. Wisconsin, 228 U. S. 115. See generally Note, Federal Inspection Legislation — A Partial Remedy for Interstate Trade-Barriers, 53 Harv. L. Rev. 1185 (1940).
  Nor have we any occasion to consider the possible applicability ito the Supremacy Clause issue of the provisions of 21 U. S. C. § 341, since neither party has made any reference to that statute either before the District Court or in this Court.
  The District Court assumed that in 1925 California growers faced no meaningful competition from Florida growers. It appears, however, that the Florida industry was well developed when the California industry was in its infancy, see Collins, The Avocado, A Salad Fruit From the Tropics (U. S. Dept. of Agriculture Bureau of Plant Industry, Bull. No. 77, 1905), 35-36. Not only does there appear to have been vigorous competition between Florida and California producers for all markets in 1925, see Popenoe, The Avocado—California vs. Florida; 61 California Cultivator, Nov. 3,1923, p. 459; but in some years during the 1920’s the Florida production exceeded that of California. See Traub, sufra, note 10, at 2. See generally Hodgson, supra, note 5, at 60, 82-83.
  The passage of the California statute was immediately and vigorously protested by Florida producers, and.a United States Senator from Florida filed an informal complaint with the Department of Agriculture, see, e. g., California Avocado Law Unfair to Florida: New Pacific Coast Maturity Standards Practically Ban All Shipments from this State, 32 Florida Grower, Nov. 7, 1925, pp. 4, 22. See also id., Nov. 21, 1925, p. 15. Even in California there was contemporaneous recognition that passage of the statute severely restricted the access of Florida growers to the markets at least of Northern California; see Hodgson, The Florida Avocado Industry—A Survey II, 66 California Cultivator, June 26, 1926, pp. 721, 743. And see 80 American Fruit Grower, Feb. 1960, p. 64.
  On the other hand, there have been suggestions that neither the adoption nor the application of the California statute reflected any discriminatory or anticompetitive purpose. In some years, California growers themselves experience great difficulty meeting the oil content requirement, and sizable shipments must be destroyed — see Demand for Avocados, 74 California Cultivator, Feb. 8, 1930, p. 167; Roche, Look Out for Immature Avocados, 87 California Cultivator, Nov. 2, 1940, p. 590; California Avocado Assn., 1937 Yearbook (1937), 88— even though the oil content of mature California avocados in good years runs substantially above 8%, see Traub, supra, note 10, at 6-8. Moreover, the California Growers’ Association has regarded its ability to market Florida fruit during the months when California fruit is not available- as strengthening rather than weakening its own market position. See Fourteenth Annual Report of the General Manager of the Calavo Growers of California (1937), 20. Plainly the questions indicated by these conflicting materials can be resolved only at a trial fully developing the Commerce Clause issue.
  At the very close of the trial, two of the three members of the court offered inconsistent views when appellees’ counsel asked for clarification concerning the status of- appellants’ disputed depositions and exhibits. One member of the court replied that “your objections stand to every word that is in these depositions here,” while another responded, “[t]hey are all in evidence subject to your objections and the Court will rule on them when it makes its ruling in the case if it is necessary.”
  Specifically, appellees offered to show that in measuring the oil content of avocados the Florida experimental test procedures did not. employ the same equipment as is used in California, the former, so it was contendéd, extracting less oil than the California equipment would obtáin from the same avocado. ■ They claimed that the average variation amounted to a failure of the Florida equipment to remove 2.9% of the oil from the fruit, and, further, that the Florida results were erratic. In addition, appellees asserted that the avocados used in the Florida experiments were hot representative of the graded, sized, and-.inspected fruit that appellants would normally market.
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