— 40— 



The three specimens show such marked divergence from 

 any of the material of the Pacific coast mainland that they might, 

 perhaps, with more propriety be regarded as a distinct species. 

 Indeed, the logic of naming the plants as a subspecies rather 

 than a species may well be questioned, inasmuch as it is doubtful 

 if intermediate specimens are extant. Certainly none have been 

 seen. The darker, more copious chaff and the stiff texture and 

 peculiar cartilaginous margins of the pinnae are very marked 

 characters ; and several competent botanists to whom I have 

 shown the material have not hesitated to express the opinion that 

 it should be regarded as of specific rank. Nevertheless, the 

 differences are only of degree and such as are to be expected 

 of plants grown under the conditions. 



Dr. Edward Palmer was the first collector to visit the island. 

 His note on this species, published by Dr. Watson (Proc. Am. 

 Acad., XI: 120. 1876), in a report on the collection, runs as 

 follows : "In large bunches ; only two seen at the northern end 

 in a rocky place inaccessible to goats, and constantly damp from 

 the prevalent fogs." Dr. Edward E. Greene, in his study of the 

 island's flora some ten years later, failed to detect the fern and 

 lists (Bull. Calif. Acad. Set., 1 : 228. 1886) only the previous 

 record. That it still persists is proven by Mr. Anthony's still 

 more recent specimens. 



THE GENUS EQUISETUM IN NORTH AMERICA. 



By A. A. Eaton. 



THIRTEENTH PAPER. 

 E. Laevigatum A. Br. 

 Rootstock granular, dull blackish, without felt; sheaths and 

 young radicles densely felted or nearly naked ; stems annual, 

 from a few inches to four feet high, usually 12-18 inches, 1 to 4 

 lines in diameter, 10-30 angled, single or clustered, smooth or 

 slightly roughened, commonly unbranched ; angles rounded, with 

 or without cross-bands of silex ; no carinal groove ; stomata in 

 a single regular row on each side of the ridges, rarely double 

 for a short distance, the grooves unarmed or with variously dis- 

 posed cross-bands and dots of silex, or in one variety with rosu- 



