ILLUSTRATIONS. XIII 
Facing page. 
Pirate 74, A. Bouteloua trinii (Fourn.) Griffiths. B. Bouteloua eriopodaTorr.. 387 
75. A. Isolated plant of Bouteloua rothrockii Vasey. B. Dense growth 
of Boutelowa rothrockit......... 2.205000 cece cece ec eee eee eeee 392 
76. Habitat of Bouteloua karwinskii (Fourn.) Griffiths, B. trinit (Fourn.) 
Griffiths, and B. stolonifera Scribn..................2.--2--2--2-- 394 
77. A. Large plant of Boutelowa aristidoides (H. B. K.) Griseb. B. Same 
species on desert mesas...........22- 22022220 eee eee eee eee eee 397 
78. Boutelowa eludens Griffiths............2. 20.00.2022 eee eee eee eens 402 
79. Boutelowa eludens Griffiths ..........222..0.00 0.00 eee eee eee 402 
80. A. Bouteloua eludens Griffiths. 8. Bouteloua texrana S. Wats....... 402 
81. Bouteloua radicosa (Fourn.) Griffiths...................2.-.-.-- .... 412 
82..A. Bouteloua filiformis (Fourn.) Griffiths. B. Bouteloua curti- 
pendula (Michx.) Torr....... 2.2... 20.0 e ee eee cece cece eee eeee 413 
83. Bouteloua filiformis (Fourn.) Griffiths.............0 22. 2ee eee ee eee 413 
TEXT FIGURES. 
Page. 
1. Algal types with associated fungal hyphe.................22222....- 9 
2. Algal types with associated fungal hyphe................2...-2-.---- 10 
3. Spermagonium of Gyrophora cylindrica and sterigmata and spermatia of 
a Cladonia........2 222.22. eee eee eee eee ee eeees 16 
4. Sticta amplissima, section.........--2222-22 0202 c cece ee ee cece eeeee 17 
5. Leptogium scotinum.......-.-.0202c cece cece eee e cece eee eee ceeeeee 19 
6. Endocarpon pusillum....-. 20. .0.00c0 cece cece eee cence eee eee eeee 29 
7. Collema microphyllum, archicarp and trichogyne...................--- 32 
8. Lecanactis abietina...........0.. cece cee eee eee e ec cee eee eee eeeee 60 
9. Gyalecta lutea.........2..2-2+24. SR oe nn 62 
10, Lecidea varians...... 222... eee ec eee cece e cee eeeeece 75 
11, Buellia myriocarpa.......-. 0.00. cece eee cece cece ee ence e eee eeee 95 
12. Sticta fuliginosa, section............. 20.0222 eee eee eee cece eee eceeeee 156 
13. Peltigera canina, section through immersed apothecium...........-..- 163 
14, Lecanora subfusca ....-2- 2.22 cece eee eee cee eee cece ceeees 178 
15. Pertusaria communis ......2..00. 20 eee eee cece eee eee eee 189 
16. Urceolaria scrupord ....2.. 2.2 eee eee cece cece eccee 232 
17. Pyrenula nitida.....222 2.0.22 e cece ee cee ee eee cece eeneee 240 
18. Dermatocarpon miniatum.......2..2. 22002 cece eee eee cece w---- 243 
19. Triaena junced.......2.2222. 20 ee ence cece cece ee eee eee e eee eeeeneee 355 
20. Pentarrhaphis scabra.....-...20020222- 20 cece eee cece cece cece eee ceeee 356 
21. Pentarrhaphis polymorpha........222-220-002 0000 cee ee cece eccceeceeee 357 
22. Cathestecwm prostratum........020. 20.20 c ence cece cece cc eeeceeee 358 
23. Cathestecum prostratum..........00.0. 2222 e eee e ccc eece 359 
24. Cathestecum multifidum .... 2.2.2... 0022 eee eee eee ee ee ceee 360 
25. Cathestecum erectum..... 2.2.22. 20-2 c cece cee eee ee eee cece eens 361 
26. Cathestecum stoloniferum...... 22.2.0 022 cece eee ee cee 363 
27. Bouteloua procumbens.........220. 22022 c cece cece eee cece cece ceecee 366 
28. Bouteloua simpler... 2.2.20. 2. e cece eee cece eee e eee ceeee 367 
29. Bouteloua simplex..... 2.2.2... cee cece cece cece cece cecee 367 
30. Boutelowa stoloniferd.........02.2. 2220202 eee eee cece eee 368 
31. Bouteloua scorpioides............. 0002 e eee ceee 370 
32. Bouteloua scorpioides..... 2.2... 0020 cece eee cece cece eee 370 
33. Bouteloua hirticulmis............0.00 2002 e cece eee 371 
34. Bouteloua hirsuta. ...... 22.2.2 cece cence eee ee 374 
35. Boutelowa gracilis... .... 2.2.2.2. 2c cee eee eee ee cee ceee 377 
36. Bouteloua breviseta.......... asad eerarercecreeseresseereescursccsess 380 
