10 



increased by the observations of Bischoff (Crypt. Genv., 1828), Miil- 

 ler (Bot. Zeit, 1845), Pnngsheim (Jahrb. f. Wiss Bot., 1863), Nord- 

 stedt (Act Univ. Lund., 1866), and de Bary (Bot. Zeit., 1875). Refer- 

 ences to the work of these and other observers will be made while 

 treating of the development of the plant. To Alex. Braun, however, 

 is due, more than to any other man, a knowledge of the complete 

 structure of all parts of the plant, and especially correct notions of the 

 relations of the genera and species of Characeae, and of the proper 

 methods of their classification. 



The oospore consists of a cell surrounded by a moderately thick 

 wall of cellulose, filled with colorless fat, grains of starch, and masses 

 of protoplasm. External to the cellulose layer, and joined to it, is a 

 thick shell, usually brown or black, formed by the enveloping cells 

 and furrowed in a spiral fashion by their twisting. This envelope, 

 consisting of five cells which arise from the base of the spore, is called 

 the sporostegium (spore-capsule), and the whole fruit, including 

 the spore proper, its basal cell and enveloping cells, the Sporo-phy- 

 diurn.* 



The furrows on the nucleus, caused by the five enveloping cells 

 of the sporostegium, are separated by ridges, often very prominent, or, 

 again, scarcely to be noticed; the prominence of these ridges is con- 

 stant in each species, and frequently serves as a distinguishing mark ; 

 the number of ridges on the nucleus, due to the number of turns of 

 the enveloping cells, is also constant and characteristic in different 

 species. 



These ridges are frequently continued downward between the 

 basal cells, and then form, as in Chara fragilis, after the soft parts de- 

 cay, fine sharp points, which serve clearly to distinguish the base of 

 the nucleus, from the apex ; the latter is often terminated by a single 

 point, caused by the prominence of the last spiral. When the ridges 

 are not prominent the base can be distinguished from the apex only 



* NOTE. In Braun, Sachs and Goebel, the fruiting organs are termed "Anther- 

 idiuin" and " Eiknospe, " the latter referring to the spore-bud, which was held by 

 Braun to be an axillary growth. Braun suggested the term Sporophyas for this 

 growth (namely, the complete fruit, oospore, basal and enveloping cells). This 

 term hi not yet been adopted by later writers, nor, indeed, has any other term 

 been suggested. Braun, in his latest descriptions, uses the term sporangium, 

 which heretofore we have used, though it is not exactly appropriate. Celakowsky, 

 in Flora, 1878, dissents from Braun's view of the "bud" nature of the spore- 

 shoot, and considers the spore a metamorphosed leaf a leaf has no significance in 

 Characeae, more than the simple outgrowth of a nodal cell but, following Cela- 

 kowsky's view, Sporophydium would still be a good term. He proposes "envel- 

 oped-oogonium," but does not suggest an appropriate technical term. We have, 

 therefore, concluded to follow the suggestion of Braun and replace the inappropri- 

 ate "Sporangium " by the most fitting Sporophydium, which will, we trust, be gen- 

 erally adopted. 



