Blackcurrant can damage both unopened and open flowers when the temperature falls below . The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged. In midsummer the strigs of green fruit ripen to edible berries, very dark purple in colour, almost black, with glossy skins and persistent calyxes at the apex, each containing many seeds. An established bush can produce about 4.5 kilograms (10 pounds) of fruit each year. Plants from Northern Asia are sometimes distinguished as a separate variety, "Ribes nigrum" var. "sibiricum", of which "Ribes cyathiforme" is considered
Acer nigrum Acer nigrum Acer nigrum (black maple) is a species of maple closely related to "A. saccharum" (sugar maple), and treated as a subspecies of it by some authors, as "Acer saccharum" subsp. "nigrum". Identification can be confusing due to the tendency of the two species to form hybrids. The simplest and most accurate method for distinguishing between the two trees is the generally three-lobed leaves of the black maple versus the generally five-lobed leaves of the sugar maple. The leaves of the black maple also tend to have a "droopy" appearance. Other differences that are not as pronounced include darker,