CHARACEJE. 



r 133 ] 



CHARACE^. 



protoplasmic sac, are earned along by it and up 

 the side of the cell, until they fall down again 

 by gravitation. The young cells from which 

 the fiiiits are developed exhibit a circulation 

 of green vesicles ; the cortical filaments have 

 a cn-culating primordial utricle without chlo- 

 rophyll-globules. 



The cu'culation is obscured in many CharcB 

 by the existence of an incrustation of the 

 cell-wall by carbonate of lime, which may 

 often be found in rhomboidal crystals. In 

 C. {Nitella) translucens, jiexilis, and other 

 species, this does not exist, and these 

 species without cortical tubes exhibit the 

 phaenomenon more clearly than the others. 

 Those species, however, wdiich are subject to 

 incrustation have comparatively little about 

 the tips of the shoots ; and if they are kept 

 growing for some time in a jar of water pretty 

 free from lime, new shoots may be obtained 

 very suitable for examination. When we 

 carefully examine the conical terminal cell of 

 a shoot, we find the following characters : — 

 The cell-membrane is distinctly laminated, 

 and thickened at the conical apex of the 

 cell ; when sulphuric acid and iodine are ap- 

 plied, the cell-w^all exhibits a thick internal 

 layer of a blue colour, indicating its compo- 

 sition of cellulose, while a thin layer extend- 

 ing all over the outside becomes bright yellow, 

 and thus presents a resemblance to the cu- 

 ticular layer of the higher plants. The cell- 

 wall is lined by a thin layer of protoplasm, 

 in which are imbedded a vast number of 

 chlorophyll-globules, closely set and arranged 

 spirally, as above stated ; a clear line extends 

 obliquely up in this layer, bare of chloro- 

 phyll. The chlorophjll-globules have much 

 the appearance of vesicles here, and contain 

 starch-corpuscles, which cause the whole 

 layer to tm^n blue wdth iodine. (See Chlo- 

 rophyll.) Within this motionless layer is 

 found the thick rotating layer of protoplasm, 

 in which again are imbedded numerous starch 

 and chlorophyll-globules, a vast number of 

 minute granules, and a number of globular 

 bodies of larger size, 1-1500", according to 

 Goppert and Cohn covered with rigid cilia. 

 The internal boundary of this layer is wavy 

 and irregular, and thus its rotation carries 

 along, to a certain extent, the watery juice 

 filling up the centre of the cell, in which he 

 numerous transparent protoplasm-vesicles, 

 ciliated bodies and granular matters. 



The fructification of Chara is very curious, 

 and its homologies are not yet satisfactorily 

 made out. Upon the branches are found 

 bodies of two kinds (either on the same or 



on different branches, or on different plant^;, 

 called the globule and the nucule. The glo- 

 bule (figs. 124, 125) is regarded as an anthe- 

 ridium ; it is a spherical body, of a red or 

 orange-colour w^hen ripe, presenting a trans- 

 parent, thickish outer coat, enclosing an 

 inner wall of curious construction. This is 



Fig. 121. 



Fig. 122. 



Fig. 124. 



Fig. 123. 



Fig. 121. Chara vulgaris. Natural size. 

 Fig. 122. Fragment of stem, magnified 15 diam. 

 showing the cortical tubes. 



Fig. 123. A section of ditto, magnified 30 diam. 

 Fig. 124. Branch with nucule and globule, 10 diam. 



