﻿Howe: New American Hepaticae 187 



decolorate or purpie-tinged cells, the somewhat smaller, more dis- 

 tinctly margined spores are fuscous-brown at maturity and always 

 show their areolae quite clearly in glycerine instead of being 

 densely black and opaque as in R. trichocarpa under the same 

 treatment, the plants are mainly smaller and less frequently dichot- 

 omous, the thallus-segments are usually comparatively broader, 

 reddish-purple below and more evidently squamigerous. 



A much nearer ally of Riccia trichocarpa is doubtless R. ciliata 

 Hoffm. of Europe. From the typical form of this, however, the 

 Californian plant is clearly distinct in the shorter and much more 

 abundant setae (these often reach I mm. in length in R. ciliata), in 

 the presence of trichomes over the sporogonia, in the rather larger 

 size of the thallus, more acute-angled dichotomy, and in the com- 

 monly black margins and sides. From R. ciliata var. intnmescens 

 Bisch., known to us only from the excellent figures and descrip- 

 tion of its author, our specimens evidently differ in the longer, nar- 

 rower segments, in the even more crowded lateral setae, those 

 toward the apex often in as many as 8- 12 irregular series, and in 

 the normal presence of 1-12 long trichomes above each sporo- 

 gonium, while in regard to the "cilia" of R. ciliata intumcscens 

 Bisch off * says, " rarius q 2 toque in superficic frondis dispersal \x\R. 

 ciliata, the tissues covering the mature sporogomum soon become 

 thin, scarious, and shining, and finally break away in fragments, ex- 

 posing the capsule and the spores, and Bischoff remarks of the 

 capsules of the var. intnmescens : "post maturitatem rupti, foveolas 

 sports re pi etas in frondis pagina snperiore rclinqiicntes" ; while in 

 R. trichocarpa the covering of the capsules remains very long in- 

 tact — indeed, in only one case out of several specimens with spores 

 evidently much past maturity, have we seen the contents of a cap- 

 sule exposed by natural agencies. 



Riccia crinita Tayl. from Swan River, Australia (Drummond, 

 no. 42), the original of which we have seen through the kindness 

 of Dr. B. L. Robinson, is close to R. trichocarpa in character and 

 number of setae, which also sometimes occur over the sporogonia. 

 But R. crinita is a smaller plant, only 2 or 3 times dichotomous, 

 with shorter, oblong rather than linear segments, the thallus is 



*Acta. Acad. Caes. Leop. Carol. Nat. Cur. 17: 1063. 1835. 



