THE MARINE ALGiE OF NEW ENGLAND. 87 



EALFSIA, Berkeley. 



(In honor of John RaJfs, an English botanist.) 



Fronds olive-brown, forming flat coriaceous or crustaceons expansions 

 of indefinite extent, composed of a single horizontal layer, from which 

 arise short vertical filaments, which are firmly united to one another so 

 as to form a solid parenchymatous structure ; fruit scattered over the 

 surface of the fronds in spots (sori), which are composed of club-shaped, 

 several-celled paraphyses, at whose base are borne the unilocular spo- 

 rangia ; hairs arising from crypts in the frond ; plurilocular sporangia 

 unknown ; growth peripheral. 



A genus containing only about half a dozen species. In its mode of growth the 

 frond resembles that of Myrionema, but the vertical filaments are not free, as in that 

 genus, but united so as to form a solid mass. R. verrucosa, the typical species, has a 

 well-developed frond, but iu R. clavata the frond is minute and the fruit-dots are usu- 

 ally confluent, so that the species has by some been placed in Myrionema. 



E. verrucosa, Aresch. (B. deusta, Berk. ; Phyc. Brit., PI. 98.) 

 Fronds lichenifonn, adherent throughout, crustaceous or membrana- 

 ceous, at first orbicular, at length becoming indefinite in outline, one to 

 six inches in diameter, zoned and irregularly tuberculated, the newer 

 lobes overlapping the older ; sori scattered; paraphyses .06-12 mm long, 

 clavate, few-celled; unilocular sporangia ovoid or pyriform, .038 mm long 

 by .019 mm broad. 



Common on rocks in pools at half- tide from ISTahant northward ; Eu- 

 rope. 



A homely, dark-colored species, which has more the habit of a lichen than an alga. 

 It abounds on the northern coast in shallow exposed pools, and is found at all seasons. 

 At first the crusts are of small size and adhere closely to the rocks, but afterwards, as 

 they increase in size, they become lobulated and rough and are easily detached. The 

 species, contrary to the statement of Janczewski, is furnished with tufts of hairs at 

 certain seasons of the year. It may occur also south of Cape Cod, but, if so, it must 

 be in a reduced form. 



E. DEUSTA, J. Ag. 



Fronds licheniform, membranaceous, attached at center, margin free, 

 irregularly orbicular, with overlapping marginal lobes, marked with 

 concentric zones and with radiating striae; spores'? 



At low water mark. 



Eastport, Maine. 



A larger and more foliaceous species than the preceding, being about .*25-30 mm in 

 thickness. Both the concentric zones and radiating strise are well marked, and the 

 species is comparatively loosely attached to the substratum. On sectioning the fronds 

 of R. deusta, the cells are seen to be arranged in lines which curved upwards and down- 

 wards from a medial plane, while a section of the frond of R. verrucosa shows the 

 cells arranged in lines which curve upwards from the attached base. 



