1 82 CHAR ACE /E 



controversy. In habit and in general appearance they resemble the Algae, 

 among which they are placed by the majority of writers. But in some 

 important points of structure they differ so widely from all known families 

 of Algje, that a true estimate of their relationships appears to require their 

 location in a distinct subdivision by themselves. With the exception 

 of the Fucaceae and the Conjugatae, the Characeae stand alone among 

 the larger groups of Cryptogams in the entire absence of true spores. 

 Seeing that the oosperm germinates directly in the soil, the embryo which 

 results from its first divisions developing directly into the new plant, 

 there is no 'alternation of generations ' in any accurate sense of the 

 term. From those classes where a true alternation of generations 

 attains its fullest development, the Muscineae and Vascular Cryptogams, 

 the Characeae differ in the complete suppression of the sporophyte- 

 generation ; while Phanerogams (at all events those Angiosperms which 

 are destitute of endosperm) deviate, on the other hand, in the suppres- 

 sion of the oophyte-generation. In the investment of the oosperm with 

 a lignified pericarp directly without any previous breaking up into 

 carpospores, the Characeae again differ essentially from all classes of 

 Algae. 



The Characeae are divided into two orders, viz. — • 



1. Chares. — Stem and branches usually corticated and calcareous; 

 leaves usually with one or two stipules at their base ; antherids usually 

 solitary on each node; crown always five-celled; pericarp often cal- 

 careous. Geiiera : Chara (L.), Lamprothamnus (A. Br.), Lychnothamnus 

 (Leon.). 



2. NiTELLE.t. — Stem and branches not corticated nor calcareous; 

 leaves without stipules ; archegones often clustered ; crown always ten- 

 celled; pericarp not calcareous. Genera: Nitella (Ag.), Tolypella 

 (A. Br.). 



Literature. 



Goppert and Cohn — Bot. Zeit. , 1849, pp. 665 et seq. 



Braun— Monber. Berlin Akad. Wiss., 1852, p. 220 ; and 1853, p. 45 ; and (Partheno- 

 genesis) Abhandl. Berl. Akad. Wiss., 1856, p. 337. 



Thuret — Ann. Sc. Nat., xvi., 1 851, p. 18. 



Montagne— Ann. Sc. Nat., xviii., 1852, p. 65. 



Nageli — Beitrage zur wiss. Bot., ii. , i860, p. 61. 



Pringsheim — Jahrb. wiss. Bot., 1863, p. 294. 



Braun — Conspectus systematicus Characearum europoearum, 1867 ; and Abhandl. 

 Berlin Akad. Wiss., 1882. 



De Bary — Monber. Berlin Akad. Wiss., 1871, p. 227 ; and Bot. Zeit., 1875, pp. 377 

 et seq. 



Bennett — Journ. of Bot., 1878, p. 202. 



Groves — Journ. of Bot., 1880, p. 97. 



