354 Copeland. — 'The Mechanism of Stomata . 
from those of Smilax (Figs 7, 8). Those of Trillium 
erectum , L., approach the Medeola type. Dioscorea villosa , L. s 
has them similar, but the inner wall is thicker, and the dorsal 
wall slants as in Helleborus. Schmidt 1 describes and figures 
the stoma of Conostylis graminea in cross-section as like that 
of a grass. 
Iris cristata, Aiton, has such stomata as Schellenberg 
describes for Iris, but according to Westermaier not all the 
species are alike. Hypoxis erecta , L., has stomata the slant 
and thickening of whose walls is suggestive of Achillea, though 
the ventral angles are noticeably thickened, and the stoma 
is long enough to act by its shape alone. 
Lenina polyrhiza , L., has the ridge of entrance as on other 
floating plants, the dorsal wall thin, and the whole stoma 
slender, appearing motile: but I have not examined it alive 
and it is open after death. Acorus Calamus , L., and Symplo- 
carpus foetidus , Salisb., have stomata of the Amaryllis type, 
but deeper than the type and narrower, and therefore needing 
the ventral angles less thickened. Those of Arisaema tri - 
phyllum , Torn, are of the Achillea type. 
Of the Orchidaceae, Aplectrum hyemale , Nutt., has already 
been mentioned as an illustration of the type of Helleborus. 
Goody era pubescens , R.Br., comes nearer the type of Amaryllis ; 
which is better represented by Spiranthes gracilis , Big., and 
*S\ cernua , Richard. The latter has a notable outer hinge. 
Cypripedium acaule , Ait., approaches the Medeola type ; and 
Orchis spectabilis , L., exemplifies it fully. 
It will economize space if the stomata of Dicotyledones are 
merely listed, with their characters : — 
PI at amis occidentalism L. Like Quercus rubra , L., Figs. 
13, 13. 
Quercus imbricaria , Mx. Different only in not being quite 
so wide. 
Pile a pumila , Gray. Narrowed to the type of Achillea. 
Codiaeum , sp., the green-house f Croton.’ Helleborus type, 
1 K. Schmidt, Ueber den Blattbau einiger xerophilen Liliifloren : Bot. Centralb. 
xlvii (1891), 1, 33, 97, 164, p. 100, 
