﻿186 Howe: New American Hepaticae 



The above is the Californian Riccia that has been referred 

 variously by American authors to Riccia ciliata Hoffm., R. tumida 

 Lindenb., R. intumescens Aust. MS., Undervv. (R. ciliata Hoffm., 



recently to Riccia hirta Aust. 

 But Riccia arvensis hirta * 



var. intumescens Bisch.) and more 



(R. arvoisis Aust., var. 'hirta Aust.). 

 known only from Mr. Austin's specimens from the neighborhood 

 of Closter, New Jersey, bears comparatively few, short, usually 

 blunt-pointed and incurved papilla-like cilia .1-.3 mm. long (not 



1 



sctac) y the thallus is strongly incrassate-carinate ventrally, the 

 margins are acute, the epidermis is very thick, of 2 or 3 layers of 



* 



The relationship of Mr. Austin's var. hirta of his Riccia arvensis to his Riccia 

 Lescuriana is still obscure to us. A study of Hep. Bor.-Am. 141 (R. arvensis) and 

 Hep. Bor.-Am. 143 (R. Lescuriana), which may fairly be considered the types of these 

 -pedes inasmuch as they were cited after the original diagnoses (Proc. Acad. Nat. Sci. 

 Philad. 1869 : 232. 1869), though not distributed until four years later, shows impor- 

 tant differences between the two. R. Lescuriana is a larger plant, with longer and 

 broader segments, and its spores are 75-100 /x in maximum diameter, with thick-walled, 

 strongly defined areolae on the outer face, 7 or 8 measuring its width, the inner faces 

 nearly smooth, minutely granulate-papillate, or very faintly and irregularly reticulate, 

 while Riccia arvensis has somewhat smaller spores (70-90/1) with all the faces distinctly 

 and almost equally areolate. But Hep. Bor.-Am. 142, issued as R. arvensis Aust. var. 

 hirta and cited by Mr. Austin after his original description of this variety, in Professor - 

 Underwood's set agrees with R. Lescuriana in every detail of importance ; in the copy 

 in the possession of Columbia University, however, we find a plant intermediate between 

 the typical R. arvensis and R. Lescuriana both as to thallus- and spore -characters, 

 mixed with R. sorocarpa Bisch. In all the specimens alluded to, the cilia when pres- 

 ent are confined to the margin, though in the original description of the var. hirta 

 (I. c. ) we read, "supra omnino hirta" which, however, in the Hep. Bor.-Am. was 

 changed to "supra usitate hirta. V But there is, in the possession of Professor Under- 

 wood, a specimen labeled in Mr. Austin's handwriting simply, u Rocks, Palisades, X. J., 

 C. F. A., Sept. 1863," in which the short cilia are not confined to the margin but are 

 scattered over the dorsal surface. The spores in the latter are nearly like those of the 

 typical Riccia arvensis, but there are differences in general habit, in the form of the 

 lobes, and in the character of the median sulcus which make its reference to the same 

 species doubtful. But whatever the relation of R. aj-vensis hirta to R. Lescuriana, none 

 of the New Jersey specimens have anything to do specifically with the Californian plant 

 described above. 



It may be remarked that R. Lescuriana was considered by Lindberg (Muse. 



* * * 



Scand. 2, 1879) a synonym of A\ Michelii Raddi ; but R. Michelii (" typica 

 e loco classico" ) according to a specimen which we owe to the kindness of Dr. Levier 

 of Florence, has spores that are distinctly reticulate on the inner faces, while those of 

 JR. Lescuriana are typically quite otherwise as already indicated ; moreover, R. Michelii, 

 together with its varieties, is said by Dr. Levier to be always dioicous, while the 

 American plant appears to be always clearly monoicous. The antheridial ostioles are 

 equally prominent in both. 



