66 The Botanical Gazette. [February, 
ment which includes a dry season. In the second species the 
air cavities are very extensive so that the shoot on drying be- 
comes roughened, and the epidermal cells are isodiametric. 
So far as we have seen the Mexican species, they are of the 
first type. 
15. AYTONIA WRIGHTII (Sulliv.) Undw. Bull. Ill. State 
Lab. Nat. Hist. 2: 43 4. ; 
Texas, C. Wright. Known only from its original spect 
en. 
16. AYTONIA ERYTHROSPERMA (Sulliv.) Undw. |. c. 43: 
1884. , 
Rocky Mountains, &. Hal/; Eagle Pass, British Columbia, 
Macoun; Almota, Washington, Piper; Lake Pend d’Oreille, 
Idaho, Leiberg; Montana: Sand Coulee, Anderson, Great 
Falls, R. S. Williams; California: Tulare co., Covdlle, Pasa- 
dena, McClatchie. 
Four additional species are known from Mexico: 
17. Aytonia crenulata (Gottsche), nom. nov. 
Plagiochasma crenulatum Gottsche, De Mex. Leverm. 266. 1863- 
Orizaba, Mexico, Farlow! 
18. Aytonia elongata (L. et G.), nom. nov. 
Plagiochasma elongatum L. et G. Syn. Hep. 513. 1847.—Gottsche, 
Mex. Leverm. 265. 1863. : 
19. Aytonia intermedia (L. et G.), nom. nov. 
Plagiochasma intermedium L. et G. Syn. Hep. 513. 1847.—Gottsché, 
ex. Leverm. 264. 1863. 
Guadalajara, Mexico, Pringle! Guatemala, F. Donnell 
Smith! 
20. Aytonia Mexicana (L. et G.), nom. nov. 
Plagiochasma Mexicanum L. et G. Syn. Hep. 519. 1847.—Gottsché, 
De Mex. Leverm. 267. 1863. 
Since the publication of my Descriptive Catalogue, a genus 
entirely new to America has been discovered in British Col- 
umbia by Mr. J. Macoun. It is the genus Clevea, generally dis 
tributed in the northern parts of the eastern hemisphere. 
21, CLEVEA HYALINA (Somm.) Lindb. 
Under rocks, Lake Agnes, alt. 7,000", Macoun; also fe 
ported by Berggren from Greenland. The specimens distrib- 
uted in Canadian Hepatice no. 75 belong (in my set) % 
Aytonia erythrosperma. 
