78 
Glyceria nervaia^ Trin. 
Glyceria paticiflora^ Presl. 
Glyceria pallida^ Trin. 
Festuca microstachys^ Nutt 
Festuca ovina, Lin, 
Festuca rubra, Lin, 
Bromus racemosiis^ Lin. 
Bromus secalinus^ Lin. 
Wilk 
Cera- 
Ccra- 
tochloa, Hook.; Thurber, Bot. Cal. ii., p. 321. 
Bromus Hookeriamis, Thurber, Bot. Wilkes's Exped., 493 ; 
tochloa grandiflora, Hook.; Thurber, Bot. Cal. ii., p. 321. 
Agropyrum repens,^^2.\\v. {Triticum, Lin.) Represented in the 
collection by several forms, one of which has the sheaths and leaves, 
as well as the lower portion of the culm, clothed with a soft pubes- 
cence. 
P J ■ 
/, 
■*- 
.- i 
Agropyrum dasysiachyiini ( Triticum, Gray ; Triticnm 
repens, var. dasystachyum. Hook.) The specimens accord 
well with the description of A, dasyanthuniy Schultes, 
and, if kept distinct from A. repens^ perhaps should be 
referred to that species. The spikelets are sometimes de- 
veloped abnormally, and one of these is shown in the 
annexed figure. 
Agropyrum canimim^ Reichenb. {Triticum, Lin.) Both 
the ordinary or typical form and the mountain form re- 
ferred to by Dr. Thurber, in Bot. Cal., ii., p. 324, charac- 
terized as having large and spreading, . usually much 
crowded spikelets Avith long, stout divergent awns. Equals 
No. 656 of Hall & Harbour's coll., 1862. 
Agropyrum divergejis, Nees. ( Triticum strigostwi, Less- 
ing.) Equals 657 of Hall & Harbour's coll., 1862. 
Ifof 
H. 
Lin. Thurber, Bot. Cal, ii., p. 325, 
Hordeum muriniim^ Lin. 
Elymus Cafiadensis, Lin. 
Elymus Sibiricus, Lin.; equals No. 651 of E. Hall's Ore- 
gon coll. 
Elymus condeyisatus^ Presl. 
Elymus Sitanion, Schult. {Sitanion clymoidcs, Raf.) 
p 
The Forms of Leaves.— Mr. Grant Allen's interesting papers on 
this subject milist have engaged the attention of all evolutionary 
botanists, and very many serious doubts must be felt as to the alleged 
adequacy of liis theory to explain the multiform and composite vari- 
ations in leaf-forms. Having been attracted lately by the modifications 
of form to be found in tlie leaves of Rhus toxicodendron, it appeared 
to me possible to find in this common plant a point of exception to 
Mr. Allen's hypothesis. Mr. Allen assumes, putting the supply of 
atmospheric moisture out of the question, or assuming it to be uni- 
form and siifificient, that a competition between neighboring leaves 
for the possession of carbon molecules, represented in the air bj 
