CLADINA. 



[ 170 ] 



CLADOPTIORA. 



cieti/) ; Nicholson, Zool. 1878, 271 ; and the 

 Bihl. of AxufAL KixGDOjr. 



C'LAUI'NA, Nyl.— A subgenus of Cla- 

 donia. 



C. si/lvrifica, amaju-ocrcea, rancjiferina, 

 and unriaiis, with their varieties, occur in 

 Great Britain. 



BiBL. Leighton, Lich.-Fl. G. B. m. 



CLADOBOT'HYUM, Nees. See Dac- 



TYLIUM. 



CLADO'DEI. — A series of Lichens (fam. 

 Lichenacei), comprising the tribes Bseomy- 

 cei, Cladoiiiei, and Stereocanlei. 



CLADO'DIUM, Brid.— A synonym of 

 some species of Bkyum. 



CLADOGRAM'MA, Ehr.— A genus of 

 Diatomaceae. 



Char. Frustules disk-shaped, valves con- 

 vex, with radiating irreguhirly forked lines ; 

 connecting-zone ring-like. 



C. caUformcum, Ehr. (PI. 51. fig. 14). 

 C. conifum, Grev. Barbadoes deposit. 



BiBL. Elirenberg, Mikrog. pi. 33 ; Gre- 

 ville, Mic. Trans. 186-5, 97. 



CLADO'MOXAS, Stein.— A genus of 

 Flagellate Infusoria. 



Char. Bodies ovate, with two equal an- 

 terior flagella, inserted in ends of a branched 

 tubular zoary. 



C. fruticidnsa, fresh water. 



BiBL. Kent, Infus. 284. 



CLADONE'MA, Duj.— A genus of Hy- 

 droid Polypes, fam. Stauiidiiclse. 



C. radiatum. Devonshire coast. 



BiBL. Hincks, Brit. Zooph. 61 ; Gosse, 

 Dev. Coast, 257. 



CLADONE'MA, Kt.— A genus of Fla- 

 gellate Infusoria. 



Char. Bodies p^oiform, oblique in front, 

 attached to a branched pedicle ; flagella 

 1 long and 1 short, lateral. 



C. la.xa. Fresh water ; on Myriophyllum. 



BiBL. Kent, Infus. 264. 



CLADO'NIA, Fee.— A genus of Liche- 

 naceous Lichens, with a somewhat shrubby 

 thallus, and fistular podetia, abundant on 

 moors and heaths. It comprises the sub- 

 genera PycnothiUa and Cladina. The Rein- 

 deer Moss (C. rancfiferina) is common in 

 such localities. 26 other British species. 



BiBL. Hook. Brit. Fl. ii. pt. 1. 238 ; Eiu/l. 

 Bot. pi. 173, 174, &c. ; Leighton, Lich.-Fl. 

 G. B. 52. 



CLADONIE'L— A tribe of Lichenaceous 

 Lichens, series Cladodei. 



Gen. Chidonia and Pilophoron. 



CLADOl'HORA, Kiitz.— A genus of 

 Confervacea; (Confervoid Algae), distin- 



guished by the branched habit of the at- 

 tached filaments. The CladopharcB are in- 

 teresting in many respects, in particular for 

 the thick laminated structure of the cell- 

 wall, the special projecting orifice in this by 

 which the zoospores are discharged, the 

 large number of the zoospores, and, lastly, 

 by the favourable opportunity they afford 

 of observing cell-division in the groAvth of 

 the branched filaments. The filaments are 

 composed of cylindrical cells attached end 

 to end, from which the branches arise by 

 the gradual protrusion of a cylindrical pouch 

 near the upper end, Avhich' pouch, becoming 

 shut off by a septum, forms the first cell of 

 the brancli. The cellulose wall acquires 

 repeated layers of thickening with age ; and 

 longitudinal and transverse strife may be 

 detected in these by careful management. 

 (See Spiral Structures.) The cellulose 

 wall is lined by a layer of protoplasm (pri- 

 mordial utricle), upon the inside of which 

 lies the chlorophyll, not, however, really 

 imbedded in it, as it is often seen retracted 

 from it in the centre of the cell. At certain 

 periods, numerous starch-granules occur in 

 the mass of chlorophyll ; but these disappear 

 when the latter is about to subdivide into 

 zoospores. When this takes place, the whole 

 mass of chlorophyll is contracted from the 

 wall, and becomes broken up, by a kind of 

 segmentation, into a very large number of 

 2- sometimes 4-cihated zoospores (these 

 sometimes occur in paii's, through imperfect 

 division). The zoospores, which are pro- 

 duced in all the cells, are discharged through 

 a special papilliform orifice in the cell-wall 

 (PI. 9. fig. 13) ; they have a distinct red 

 spot. Numerous supposed species inhabit 

 fresh, brackish, or sea-water in Britain ; 

 some are veiy common and abiuidant ; but 

 it is difticidt to draw out difterential cha- 

 racters, as the habit appears to be A"ery 

 variable. They are Conferva of older 

 authors. 



C. ylomerata, DiUw., is of a dark green 

 colour, and grows commonly in long drawn- 

 out skeins, in pure running water ; but it 

 seems to be identical with the rarer C. cega- 

 gropila, L., which forms dense balls 2 to 4" 

 in diameter, in lakes ; while there is also a 

 marine variety. 



C. crispata, Sm., is perhaps not distinct ; 

 it forms yellowish or dull green strata, 

 everywhere common in fresh water ; fre- 

 quent in brackish water. It is the same as 

 C.Jlarescens, Both. C. fracta, Fl. Dan., is 

 probably a form of this. 



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