Houstonia (plant) fruit is an often roughly cordate capsule enclosing many seeds and which usually dehisces via a suture across its apex. "Houstonia" consists of 20 species native to North America. Another 5 species are classified in the genus "Stenaria"; "Houstonia" without "Stenaria" is paraphyletic. Close relatives of the genus are "Oldenlandia microtheca" and, more distantly, "Arcytophyllum". Its members superficially resembles species of the genus "Myosotis" (Forget-me-nots), but are distinguished from the latter by having only 4 sepals (petals) instead of 5. Species accepted as of May 2014 are: Houstonia (plant) Houstonia (bluet) is a genus of plants in the family Rubiaceae.
How many angels can dance on the head of a pin? about how many could perch at the same time on the head of a pin"". Dorothy L. Sayers argued that the question was "simply a debating exercise" and that the answer "usually adjudged correct" was stated as, "Angels are pure intelligences, not material, but limited, so that they have location in space, but not extension." Sayers compares the question to that of how many people's thoughts can be concentrated upon a particular pin at the same time. She concludes that infinitely many angels can be located on the head of a pin, since they do not occupy any space there: