NOSTOCHACEiE. 



[ 464 ] 



NOSTOCHACEiE. 



garden walks, rocks, barren pastures, &c. ; 

 very common in autumn and winter. 



8. N. verrucosum, Vauclier. Frond blad- 

 der-shaped, softl}' -leathery, fuscous-green ; 

 filaments spiral, densely entangled, joints 

 globose ; periderm gelatinous, soft, green or 

 dirty brown. Vaucher, Hist, des Conf. t. 

 16. fig. 3; Kiitzing, Tab. Phyc, vol. xi. pi. 

 9. fig. 2 ; Thuret, Ann. des Sc. nat. ser. 3. 

 vol. ii. pi. 9. figs. 1-4 ; Hassall, Br. Fr. Alg. 

 pi. 75. fig. 1. On stones in streams. 



9. N. variegatum, Moore. Frond terres- 

 trial, expanded, gelatinous, livid, variable in 

 shape; filaments rather distant ; joints oval 

 and variable in size. Hassall, Br. Fr. Algce, 

 pi. 74. fig. 3. On a moist bank in Ireland. 

 A doubtful plant, perhaps referable to a 

 diff*erent genus of the Nostochaceae. 



BiBL. The works above quoted; Itzig- 

 sohn, Bot. Zeit. xii. p. 521. 1854; Sachs, 

 Bot. Zeit. xiii. p. 1 (1855). 



NOSTOCHACEiE.— A family of Confer- 

 voideae. A tribe of Algae, composed of plants 

 forming gelatinous strata or definitely formed 

 gelatinous balls or masses, either on damp 

 ground, or floating at the bottom of water ; 

 consisting of minute, unbranched, usually 

 moniliform, microscopic filaments, tranquil 

 or oscillating, imbedded in a mass of muci- 

 laginous or sometimes firmish substance 

 (the amorphous matrix is produced by the 

 fusion of the special gelatinous sheaths of 

 the individual filaments) ; filaments finally 

 breaking up. Cells of the filaments of three 

 kinds : — 1. ordinary cells ; 2. vesicular cells, 

 usually large and without granular matter, 

 frequently with erect hairs ; 3. sporangia or 

 spermatic cells, produced by the enlarge- 

 ment of the ordinary cells, globular, elliptical 

 or cylindrical. [Some of the genera are de- 

 scribed as without sheaths ; but this is very 

 doubtful, and probably depends on imperfect 

 observation.] 



Synopsis of British Genera. 



I. Aphanizomenon. Filaments un- 

 branched, cylindrical, oscillating, with evi- 

 dent sheaths, cohering laterally into flat plu- 

 mose lamellae, expanding in the middle into 

 usually single, distinct spermatic cells, of 

 unequal length, vesicular cells absent (?). 

 Floating on stagnant pools. 



II. Trichormus. Filaments moniliform, 

 motionless, entangled in an indefinite mu- 

 cous mass, without evident sheaths ; the 

 joints of cells filled with contents (hologo- 

 nimic), here and there expanding into (inter- 

 stitial) globular s})ermatic cells, which are 



separated from the vesicular cells by ordi- 

 nary cells. 



III. Sph^rozyga. Filaments mostly 

 moniliform, motionless, involved in an amor- 

 phous mucous matrix; the cells hologonimic, 

 here and there expanding into elliptical 

 spermatic cells, in groups of two or more, 

 connected by a vesicular cell ; sheaths (ap- 

 parently) none. 



IV. Cylindrospermum. Filaments 

 jointed, composed of hologonimic cells, and 

 involved in a common mucous matrix, social, 

 straight or curved, sometimes oscillating; 

 spermatic cells cylindrical, rounded at both 

 ends, granular, interposed between the ordi- 

 nary cells and terminal vesicular cells. 



V. Spermosira. Filaments articulated, 

 cylindrical, oscillarioid, motionless, with an 

 evident sheath ; ordinary cells discoid, at 

 length swelling into concatenate moniliform 

 spermatia, separated by ordinary cells from 

 the vesicular cells, which are interstitial, 

 single or two together. 



VI. Dolichospermum. Filaments sim- 

 ple, generally moniliform, without evident 

 sheaths, aggregated into a gelatinous stra- 

 tum ; spermatic cells interstitial, elongated, 

 separated by the ordinary joints from the 

 vesicular cells. 



VII. CoNioPHYTUM . Filaments simple, 

 without evident sheaths, rarely spiral, curled 

 and interwoven into a minute, distinct frond ; 

 vesicular cells interstitial, spermatic cells 

 formed sometimes of the cells next the vesi- 

 cular cells, sometimes from those distant 

 from them. 



VIII. MoNORMiA. Frond or phycoma 

 definite, gelatinous, elongated, linear, spirally 

 curled and convoluted, enclosing a single, 

 continuous moniliform filament ; vesicular 

 cells interstitial; s])ermatic cells developed 

 from joints most distant from the vesicular 

 cells. 



IX. NosToc. Phycoma or general mass 

 of the plant enclosed by a periderm formed 

 by the condensation of the surface, determi- 

 nate, globose or spread out, of variable form, 

 gelatinous or mucous, coriaceous, soft or 

 hard, elastic, slimy, containing moniliform, 

 simple, curved and entangled filaments, 

 composed of hologonimic cells, imbedded 

 in a continuous amorphous gelatinous ma- 

 trix, spermatic cells globose, interstitial, 

 larger than the ordinary joints of the fila- 

 ments. 



Exotic genus. Trichodesmium. Fila- 

 ments straight, short, unbranched, without 

 evident sheaths, in simple sei)arate bundles. 



