Tin: makim: alc;.i: uf m:\v l.nuland. 147 



postomos l)y whicli tin* spores aro tliscliar;^''*^- Ilowovi-r ill defined the present genua 

 may be, there is no ditlieulty in recojjjnizinj; at sight our only species. 



A. TLICATA, Fries. [Gi/mnof/ongrus 2)JicaiHS,Kniz.', IMiyc. Brit., PI. 

 2SS. — Gigartinn pUcata, Lam.x. — S2)h(vyococcus jylicatus, Ag.) 



Fronds liorny, terete, tilit'orm, very irregularly branched, entangled, 

 branches di-triehotonious, with lateral, often seennd, branches, axils 

 rounded, terminal divisions elongated; cystocari)s and tetraspores? 



Var. FASTIGIATA. 



Fronds regularly dicliotomous, terminal segments equal. 



On rocks and alga^ in exposed tide pools. 



From ^Xew York noithwardj Etirope; !N^orth Tacitic. 



Fonning very irregularly branched, rigid tufts several inches in diameter. Tho 

 color is usually nearly black, becoming on exposure yellowish or greenish. More wiry 

 and rigid than any of our other Floridew. 



CYSTOCLONIUM, KUtz. 



(From Kvarcc, a bladder, and kXuviov, a small twig.) 



Fronds fleshy, succulent, terete, decompoundly branched, composed 

 of three strata of cells, an axile series of loosely interlaced filaments 

 formed of delicate elongated cells, surrounding which is a layer of large 

 rounded cells and a cortical layer of small roundish-angular cells ; an- 

 theridia in spots on the upper part of the fronds, interspersed among 

 the unchanged cortical cells ; tetraspores zonate, scattered in the cor- 

 tical layer j cystocarps large, immersed in the frond, usually prominent 

 at one side, with a single carpostome. 



The account given above of the structure of the frond refers to the appearance pre- 

 sented in sectioning the mature plant. A study of the development shows that the 

 external and medial layers really are derived from the axial filaments, or rather that 

 all three are formed from a common set of filaments at the apex of the frond. The 

 frond of Cifntoclonium might be mistaken for that of Ilhahdonia, but the fruit is very 

 ditVerent. The genus comprises about half a dozen described si^ecies, but only one is 

 at all well known. 



C. PURPUBASCENS, Kiitz. {Ihjpnca purpurascenSj Harv., Phyc. Brit., 

 n. 110.) 



Fronds brownish ro.^e-colored, six inches to two feet long, an eighth 

 to a quarter of an inch in diameter, terete, subpinnately decompound, 

 much branched, branches alternate, elongate, beset with alternately 

 decompound branchlets which taper at each end; cystocarps numer- 

 lous, large, often forming nodose swellings in the branches. 



Var. ciURiiosA. 



The branches drawn out into long, twisted tendrils. 



