— el- 

 s' Plagiochasma rupestre (Forst.) Steph. Without definite locality or 

 date, H. H. Rushy; Soldier Canyon, Santa Catalina Mountains, 19 13, W. A. 

 Cannon; same locality, G. E. Nichols. 



6. Plagiochasma Wrightii Sulliv. Nogales, 1902, D. T. MacDougal. 



7. Grimaldia californica Gottsche. Cottonwood Springs and Soldier 

 Canyon, Santa Catalina Mountains, 1913, G. E. Nichols; Bear Canyon and Sabino 

 Canyon, Santa Catalina Mountains, F. Shreve. The specimens are all sterile, 

 so that their determination must be considered provisional. 



8. Reboulia hemisphaerica (L.) Raddi. Willow Spring, 1890, E. Palmer 

 535; Huachuca Mountains, J. G. Lemnion 210; L. N. Goodding 752; Soldiers 

 Canyon, Santa Catalina Mountains, G. E. Nichols; Sabino Canyon, Santa Cata- 

 lina Mountains, J. J. Thornber; same locality, F. Shreve; Clearson's Mill, Graham 

 Mountains, F. Shreve. 



9. AsTERELLA CALIFORNICA (Hampe) Underw. Bright Angel Trail, bottorr 

 of Grand Canyon, 1913, G. E. Nichols. The specimens seem to be dioicous, 

 but the absence of carpocephala makes their determination doubtful. 



10. CoNOCEPHALUM CONICUM (L.) Dumort. Frye Canyon, Graham Moun- 

 tains, 1 9 14, F. Shreve. 



11. Marchantia paleacea Bertol. Huachuca Mountains, 1910, L. N. 

 Goodding 824. 



12. Marchantia polymorpha L. Miller's Canyon and Wickersheim's 

 Cabin, Huachuca Mountains, 1909, L. N. Goodding iii, 362. 



13. FossoMBRONiA LONGiSETA Aust. Cherry Creek, Santa Catalina Moun- 

 tains, 19 13, G. E. Nichols. 



14. Plagiochila asplenioides (L.) Dumort. North side of Mt. Lemmon, 

 Santa Catalina Mountains, 1912, D. S. Johnson. 



15. Cephaloziella Hampeana (Nees) SchifTn. Cottonwood Springs, 

 Santa Catalina Mountains, 1913, G. E. Nichols. 



16. Cephaloziella myriantha (Lindb.) Schiffn. Bear Canyon, Santa 

 Catalina Mountains, 1913, G. E. Nichols. 



17. Cephaloziella papillosa Douin. Bear Canyon, Santa Catalina 

 Mountains, 19 13, G. E. Nichols. 



18. Scapania undulata (L.) Dumort. Marshall Gulch, Santa Catalina 

 Mountains, 1912, D. S. Johnson. 



19. Radula complanata (L.) Dumort. Bear Canyon, Santa Catalina 

 Mountains, 19 13, G. E. Nichols. 



20. Frullania mexicana Lindenb. North side of Mt. Lemmon, Santa 

 Catalina Mountains, 1912, D. S. Johnson. 



21. Anthoceros laevis L. Xero-montane Garden and Sabino Canyon, 

 Santa Catalina Mountains, 1914, F. Shreve. 



Of the species listed Nos. I-12 belong to the Marchantiales, Nos. 13-20 to 

 the leafy Jungermanniales, and No. 21 to the Anthocerotales. The large pro- 

 portion of thalloid forms is an interesting feature of the flora and indicates its 

 strongly xerophilous character. Many of these forms are able to pass through 

 long periods of drought in a quiescent state and then to recover and resume their 



