194 CHARGE AUSTRALES ET ANTAUCTICjE. 



with a very inconspicuous one, as may be seen in Cliara Drummondii. 

 On the other hand, in many of those species, the superior whorls, which 

 contain the fructification, are covered with a jelly, pellucid and very 

 sliiny, as is expressly noted in the manuscript communications of 

 Mr. Drummond to Sir W. Hooker. In gênerai I cannot help paying 

 my tribute of admiration to the perspicacity and carefulness of Mr. 

 Drummond in collecting thèse minute and difficult plants, the species of 

 which, as well as the mostly separated sexes, he exactly distinguished, 

 and even took the pains to detect germinating spécimens of several 

 of them. 



In regard to the generic division of Cliaracea, I remark, that I hâve 

 found a sufficient character to distinguish the two gênera of Nitella and 

 Cliara, origïnally foundcd only on the habit. This character consists in 

 the construction of the stigma, or rather the coronula of the seed, which 

 is formed by the summits of the five involucral leaves spirally involving 

 the spores, and constituting the striated seed-vessel. This coronula 

 consists, in the genus Cliara, of five cells, which form a simple circle, 

 and sometimes spread themselves in the form of a star ; while, in the 

 genus Nitella, the coronula consists of ten cells, forming two circles 

 one lying above the other, and never spreading. Besides, the coro- 

 nula of Char a is persistent, that of Nitella generally falling off before 

 the complète maturation of the seeds. The character on which the gênera 

 Cliara and Nitella were founded by Agardh, consisting in the coated 

 (striated) or uncoated stems is not universally available : ail Nitella^, 

 indeed, hâve uncoated stems ; but ail Charas hâve not coated stems. 



Each of thèse gênera may be divided in two subgenera, according to 

 the position of the antheridia or globules. In most of the Nitella 

 they are terminal, that is, situated on the summit of the chief ray of 

 the leaves (branches of the whorl), in the midst of the secondary rays, 

 which form the furcated division of the leaf. This is the case in the 

 true Nitella, N.Jlexilis, syncarpa, translucens, gracilis, ienuissima, &c. 

 In some other species, as N. nidijica anàfasciculata, the antheridia are 

 placed laterally on the joints of the articulated chief ray of the leaves, 

 between the latéral rays, which never attain the length of the chief ray. 

 This subgenus I call Tolypella. 



The genus Chara may be divided into Cliara, in the stricter sensé, in 

 which the antheridium takes the place of one of the little foliola (com- 

 monly called bracteaî). lu the monœcious species of this division 



