ANTHOCEROS 183 
то. Longitudinal section showing early stages in the formation of the tuber, 
У 47. The section is somewhat oblique and does not exhibit the full thickness of the 
ІІ. Section through a well-grown tuber, Х 53. 
12. A single interior cell from fig. 11, Х 305. 
13. Longitudinal section through the costa, Х 53 
14 and 15. Transverse sections of thallus segments, 53. 
I6. Outlines of two other transverse sections of thallus segments, У 23. 
17. Involucres, Х 12. . 
Figs. 1-6 and 9-17 from specimen collected in Mill Valley, Marin Со., February 
22, 1896—mostly drawn from material fixed with 1% chromic acid and preserved in 
alcohol; 7 and 8, from same locality, March 19, 1892. С 
18. Involucre of Anthoceros polymorphus Raddi, y dichotomus Raddi, ex herb. 
Raddi, 12. 
2. ANTHOCEROS PEARSONI М. A. Howe, Bull. Torr. Bot. Club, 25: 
B. 0. 322, 327. 1806. 
Thallus smooth, prostrate or ascending, rarely erect, тоз! 
irregularly dissected ; the major segments linear or elongate-flabel- 
iform, 5-20 mm. x 1-5 mm., often intertangled, sparingly lobed 
elongate-cylindrical, 2.3-3.3 mm. x .5-.85 mm., sometimes decum- 
bent at base, the mouth entire, repand-dentate, often lacerate with 
age, now and then scarious : capsule pale brown, yellowish, or drab, 
slender, sulcate, 8-32 (mostly 20-24) mm. x .24—4 mm., rather 
thick-walled, the valves finally thin and often twisted, stomata abun- 
dant ; columella filiform, naked ; spores yellow, the convex face with 
a few (8-15) small, crescentic, rarely obsolete warts, otherwise 
smooth or most faintly granulose, 35—50 in maximum diameter ; 
pseudo-elaters dilute yellow or occasionally tinged with brown, of 
1-4 cells, geniculate and variously contorted, often branched, the 
cells 30-80 и x 6—10 p, with wall of nearly uniform thickness. 
On moist banks and dripping rocks. Mill Valley (no. 16, 
May 7, 1892—the type—and 1205), Olema—also collected in 
