VIII. CHAEACE^. 



919 



Ckara. 



Portion of stem cut vertically 



(mag.). (BischofE.) 



Xlhai-a Mspida. 



Osnfcraloell bearing the chambered filaments, of wHch caoh 



cell contains an arttheroaoid. 



C. fragUis. 

 Sporangium cut 

 vertically (mag.). 



stem being converted into starchy tubers of various shapes, or by whitish crustaceouS 

 bulbils, developed at the joints of the stems. 



Stems tubular, cylindric, leafless, jointed, sometimes transparent and flexible, 

 even after being dried {Nitella); sometimes opaque and fragile, even before being 

 dried {Ghara); often covered with calcareous salts, usually branched ; joints composed 

 of a cylindric tubular cell, naked {Nitella), or clothed with a sort of sheath formed 

 of smaller tubes united together, and giving rise on the outer surface to longitudinal 

 and oblique striae {Ghara); the joints or tubes are filled with a coloui'less liquid, in 

 which pale green granules float ; their inner wall is covered with green uniform 

 granules, arranged in a chaplet ot longitudinal parallel very regular series, and more 

 or less pressed together ; these Series are oblique with relation to the axis of the tube, 

 an obliquity which is the result of the greater or less twisting of the tube. The 

 series of green granules covers the whole inner surface of the tube, with the excep- 

 tion of 2 parallel opposite bands, which are quite free from them. This arrange- 

 ment of the granules obtains both in the simple tube of Nitella, and in the central 

 and peripheric tubes of Chara ; but the intracellular circulation which is described 

 at p. 147, and which has exel-cised the sagacity of many physiologists (Corti, Slack, 

 Sachs, Schumacher, &c.), is best observed in the central tube of Ghara when deprived 

 of its envelope of cortical tubes. This circulation does not extend along the 2 bands 

 without granules, which proves, as supposed by Amici, and confirmed by Dutrochet, 

 that the intracellular currents take place under the influence of these series of 

 globules fixed to the walls of the tube, and are determined by an action of these 



