CEEAMIACEAE. 629 



Seirospora purpurea M.A. Howe,sp. dov. Plants purple-lake or <lahlia- 

 carmine, forming dense, more or less felted, pulvinate tufts 1-2^ cm. high, rami- 

 fication repeatedly decompound, for the most part obscurely qu]n(^uefarious, the 

 ultimate ramelli dichotomo-subdistichous and often subfastigiate; main axes 

 0.15-0.25 mm. in diameter at base, rather sparingly corticated for one half 

 or more of their length by narrow-celled rhizoids, and in basal parts clothed 

 in addition by free sometimes spirally entwined rhizoids, occasional cells of 

 the upper ramuli also sending out elongate, free, long-celled, simple or spar- 

 ingly branched rhizoids; largest uncorticated cells of the main axes 40-95/* 

 in diameter, subcylindric or slightly enlarged at the noiles, lA-2i times as 

 long as broad, their walls 8-20^ thick; cells of the ultimate ramelli mostly 2-4 

 times as long as broad, the terminal obtuse, 6-13 /u. in diameter, hairs apparently 

 wanting; dioicous; antheridia ovoid, lance-ovoid, dimidiate-ovoid, or ellipsoid, 

 occurring singly at the nodes, erecto-patent, often incurved, 48-65 m high, 

 26-40 /u, broad; cystocarps somewhat hemispheric, 0.3-0,4 mm. broad, composed 

 of free, erecto-patent, moniliform, sporogenous filaments, the ellipsoid or ovoid 

 carpospores 35-40 /u; long; tetrasporangia scattered, solitary at the nodes, 

 obovoid or ellipsoid, 50-65 ijl in maximum diameter, tetrahedrally divided. 

 (Phye. Bor.-Am. 2045, as Callithamnion byssoideum jamaiccnse Collins.) 



Type from a cave, Gravelly Bay, A. B. Hervey (Phyc. Bor.-Am. 2045) in 

 the herbarium of the New York Botanical Garden. 



Seirospora purpurea bears some resemblance in habit to small dense con- 

 ditions of Callithamnion coryrribosum and C. byssoides, but is easily distin- 

 guished by the sheathing of the basal parts of the main axes by free rhizo'ds 

 in addition to the cortications, by the frequently rhiziniferous cells of the 

 smaller branches and the consequent more or less felted condition of the tufts, 

 and more especially by having the cystocarp of a Seirospora, with its free 

 sporogenous filaments, instead of the solid cystocarp of a CaUithamniun with 

 its common enclosing wall. The European Seirospora? GaiUonii (Crouan) 

 De-Toni is possibly a nearer relative. The Jamaican CaUithajnnion byssoi- 

 deum jamaicense Collins (Phyc. Bor.-Am. 443) is manifestly a different thing. 

 The cells of S. purpurea are apparently all uninucleate. Endemie. 



Antithamnion cruciatum (Ag.) Naeg. is a delicate rose-colored or dingy 

 red plant, mostly 1-2 inches high. Its main axes are rather few, its secondary 

 branches are comparatively short and four-ranked, being opposite and decus- 

 sately paired or in whorls of four. It is monosiphonous and uncorticated 

 throughout. At the apices of the main axes, the branches and branchlets are 

 very densely crowded, more or less incurved, more intensely colored, and, when 

 pressed and dried, the effect is often slightly suggestive of the terminal "eye" 

 of a peacock's tail-feather. St. George's (Hervey). (Phyc. Bor.-Am. Sinj.) 



Crouania attenuata (Bonnem.) J. Ag. is a very gelatinous, much 

 branched, filiform, monosiphonous, and uncorticated plant 1-4 inches long, 

 varying in color from light rose to dingy purple. The main branches are 

 irregular and they bear at their nodes pairs or whorls of fastigiate, erecto- 

 patent or slightly incurved, several times dichotomous or trichotonious short 

 branches, the successive whorls close-set and confluent in the younger parts, 

 often separate and giving a beaded or moniliform appearance in the older 

 parts. The general habit of the plant is very suggestive of certain species 

 of the fresh-water genus Bairachospermum. The younger main branches are 



35 



