20 RICCIACEAE 
PLATE 88. КІССІА TRICHOCARPA. 
г and 2. Portions of the plant, natural size. 
3. Terminal segments of a young thallus, dorsal view, X 
4. End of thallus lobe from fig. І, with ostioles and a sporogonium, X 10. 
. Lateral view toward apex of a thallus-segment, showing the numerous tri- 
chomes, 20. 
6. Marginal trichomes, 53. 
7- Portions of thallus exhibiting the trichome-bearing elevations above the cap- 
sules, Х 20. i 
8-13. Outlines of transverse sections about то и in thickness at selected points 
from near the apex to the old and shriveled base, X 23. e trichomes do not appear 
so abundant as might be expected from the material used for microtome sectioning, 
which may be explained from the thinness of the sections and by the fact that the de- | 
tached sections and fragments of the trichomes have not always adhered to the glass 
slides. Fig. 8 shows small median scales. 
I4. Epidermis and subjacent cells from а younger portion of the thallus, 225. 
The superficial layer is here represented as composed of collapsed cells. In the ex- 
treme apical region only they are papilliform. 
I5. Epidermis in older parts of the thallus, X 225. "The collapse and disintegra- 
tion of the cells of the outer layer is so complete that only a structureless cellulose film 
remains. 
16. Cross-section of thallus showing the cell structure and a young sporogonium, 
J 
17. Spores, X 305. , 
Figs. 1, 2, 4-7 and 17 from Hep. Аш. no. І 38 collected near Stanford University, 
April, 1892, by Prof. D. Н. Campbell; figs. 3 and 8-16 from material fixed with 1 per- 
cent. chromic acid and preserved in alcohol, collected by the author near Berkeley, 
California, February 8, 1896. 
3. КІССІА CarrrogNicA Aust. Bull. Torr. Bot. Club, 6:46. 1875. 
Thallus forming light green, somewhat glaucescent rosettes 
8—18 mm. in diameter, concolorous beneath, reticulate above, often 
minutely puberulent or scurfy when moistened ; the principal di- 
visions 1-3 times dichotomous; terminal segments short-oblong 
or obovate, I-2 mm. wide, bearing toward the subtruncate or re- 
tuse apex few or numerous whitish or subfuscous, mostly slender 
and sharp-pointed cilia .16-.4 mm. in length, the commonly ob- 
tuse margins elevated and somewhat tumid when young, the 
median sulcus broad and obtuse except at the extreme apex, van- 
ishing backward, the segments more or less concave dorsally on 
