100 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
KEY TO SPECIES. 
Thallus loosely affixed, the lobes inflated. 
Greenish gray above; lobes flattening at border. .......... 12. P. physodes. 
Gray above; lobes linear and deeply cleft............... _. 13. P. enteromorpha. 
Thallus closely affixed, horizontally expanded. 
Thallus light colored. 
Thallus light straw-colored or pale greenish. 
Beneath black. 
Small and narrowly lobed; with KHO + 
yellow...........0..20.22020222-020225-. 14. P. subcapitata. 
Large and broadly lobed. 
Thallus finely wrinkled; medulla with 
KHO + yellow, with Ca(ClO),—.. 1. P. eylisphora. 
Thallus. smooth; medulla with KHO— 
with Ca(ClO), + red............. 2. P. olivetorum. 
Beneath dark but not black. 
Broadly expanding. 
Thallus with KHO + yellow; fruiting 
freely....22..22. 2000002020 3. P. conspersa. 
Thallus with KHO —-; sterile. ........... 4. P. subconspersa. 
Not broadly expanding; lobes narrow. ....... 3a. P. conspersa sten- 
ophylla. 
Thallus light gray. 
Smooth above. 
Lobes ascending; sterile with us.............. 5. P. perlata, 
Lobes lessascending, broadly laciniate; fruiting 
freely... ...2.2-..--2--- 220202 .2ee eee 6. P. tiliacea, 
Reticulate-lacunose above....................... 7. P. saxatilis. 
Thallus dark brown. 
Beset with concolorous small warts.................. 10. P. exasperata, 
Not beset with warts. 
Slightly wrinkled above. 
Spores more than 8......................2-2-- 9. P. multispora, 
Spores not more than 8...................... 11. P. glabra. 
Not wrinkled above, glistening..... cee eeeeeee .... 8. P. olivacea. 
1. Parmelia cylisphora (Ach.) Wain. 
Thallus orbicular, expanded, sometimes to a width of 20 cm., pale greenish yellow, 
interruptedly radiate, rugose, pulverulent, isidiose, except at the border lobes, these 
smooth, broadly laciniate, round-lobed, the periphery suberect, entire or crenate, 
beneath deep black, the periphery light brown, with short, black, dispersed rhizine, 
smooth, with KHO both layers yellow, Ca(ClO).=; apothecia rather rare, when present 
medium large, the largest barely 2 mm. wide; disk concave, red brown, with an 
erect, often pulverulent thalline margin; epithecium subcontinuous, sordid greenish 
yellowish; thecium 52 to 56 » high, the lower half colorless; hypothecium colorless; 
asci inflated or cuneiform, 35 # long, 16 » thick; spores ovoid-ellipsoid, 10 to 16 # long, 
7 to 9 mw thick. 
On bowlders and dead and living bark. Santa Monica, San Gabriel, and Verdugo 
Mountains. North and South America; Europe; Hawaiian Islands. 
2. Parmelia olivetorum (Ach.) Nyl. 
Thallus pale greenish (a specimen determined by Nylander in 1898 now dusky 
yellow in the herbarium), orbiculate, widely spreading, from 5.5 to 12 cm. in width, 
laciniate-lobed, the lacinis: contiguous and the border entire or coarsely round-crenate; 
