THE MAEINE ALG.E OF NEW ENGLAND. 161 



are in the somewhat swollen tips of the frond. The present species is usually found 

 washed ashore from deep water, hut on the northern coast is found also in deep tide- 

 pools. When dried it becomes brittle and does not adhere to paper. 



Suboeder SPH^ROCOCCOIDE^E. 



Fronds cylindrical or membranaceous, substance often very delicate; 

 antheridia forming superficial patches or occasionally contained in 

 sunken cavities; tetraspores cruciate, zonate, or tripartite, often col- 

 lected in spots (sori) on the surface; cystocarps external, liemispli erica 1 

 or flask-shaped, spores arranged in moniliform filaments, which radiate 

 from a basal placenta, carpostome distinct. 



The present suborder is by Agardh and some other writers divided into two, the 

 Sjrficerococcoidccv, which include rather coarse cartilaginous algae, which are cylindrical 

 or somewhat compressed, but hardly membranaceous, and the Delcsseriecv, which are 

 rosy-red and of delicate texture and distinctly membranaceous. The fruit, however, 

 is very similar in both groups. The spores are arranged in subdichotomous filaments-, 

 which radiate from a basal placenta, which in some genera, as Gracilaria, projects far 

 into the cavity of the cystocarp. The suborder differs from the Rhodymeniece in that 

 the moniliform arrangement of the sporiferous filaments is preserved even at matu- 

 rity, and the filaments are distinct from one another and not held together by a gelat- 

 inous envelope. It must, however, be admitted that there are genera which seem to 

 indicate a close relation between the two suborders. 



GEINNELLIA, Harv. 



(Named in honor of Mr. Henry Grinnell, of New York.) 



Fronds rosy-red, occasionally purple, delicately membranaceous, with 

 a slender percurrent midrib, composed of a single layer, at the midrib 

 of several layers, of large polygonal cells ; antheridia in tufts on both 

 sides of the frond ; tetraspores tripartite, in swollen spots on the frond; 

 cystocarps sessile on the frond, flask- shaped, spores in dichotomously 

 branching filaments arising from a basal placenta. 



A genus comprising a single species, which is found from Cape Cod to Norfolk, sep- 

 arated from Ddcsseria because the tetraspores are formed in incrassated spots on the 

 frond. The genus is too near Ddcsseria, of which it should perhaps form a subgenus. 



G. Americana, Harv., Ner. Am. Bor., Part II, PI. 21 b. (Delesseria 

 Americana, Ag. — Aglaiophyllum Americanum, Mont. — Cryptopleum 

 Americana, Kiitz.) PI. XIII, Figs. 2-4. 



Exs. — Alg. Am. Bor., Farlow, Anderson & Eaton, No. 61. 



Fronds dioecious, four inches to a foot and a half long, one to four 

 inches wide, lanceolate, tapering at the extremities, occasionally bifid 

 or proliferous, margin smooth or wavy ; antheridia in small spots on 

 both sides of the frond ; tetraspores scattered over the frond in thickened 

 spots ; cystocarps scattered, sessile, flask-shax^ed. 

 S. Miss. 59 11 



