[79]

Contrary effect.─

Linn. Trans. Vol 18. p. 1. "J. Woods Observations on the genera of Europæan grasses"

It has often been observed, that when a great number of plants is united in a very natural class, it is difficult to distinguish the genera & when the genera are natural, it is often hardly possible to discriminate the species. Both these difficulties occur amongst the grasses.

p. 2. The manner in which a single species is transferred by different authors to different genera shows that I am not singular in finding great difficulties in this particular." Bromus pinnatus became Festuca, by Haller & Decandolle Triticum — then a new genus.— then Bromus again — then Triticum again, & some of the Tritica into Festuca — &c &c &c

p. 7. "The tendency of certain plants towards a certain plant towards a particular structure, even when the structure

[79v]

is not developed, is very important & was perhaps first first distinctly implied in the observations of Mr. Brown." ie as he refers to the necessity of "some indications in the plant itself"— this must refer to some rudiments?? & Mr Brown says proposes division, "on the tendency of the genera to perfect to perfect the lower, the upper or only central floret speaks of "abortive florets" repeatedly

"When there is no certain & definite character, different persons will judge of relationship in different manner.— — "in arranging groups from a general sense of comparative similarity no two Botanists? wd perhaps exactly agree

p. 11. "in grasses where perhaps the genera are formed in many cases for the convenience of the student" Even the pubescence of certain parts, a character in general of little value even in the determination of species, has been universally admitted as part of the character of a genus.—

p. 37. says Desclampia has "usually" the more or less perfect indication of the third floret, which is wanting in Aira"

p. 39. "the Festucaceæ on the whole is a very distinct tribe though closely allied by some of its genera to the Arenacea on the one hand & to the Hordeaceæ on the other"

p. 45. "Festuca is a genus comprehending two or 3 different appearances, wh. are not easily united under one character, & yet cannot be well separated."