415 
Order CCLXXXVIII. CHARACE^. The Chaea Tribe. 
CHARACEiE, Rich ct Kunth in Humb. et Bonpl. N. G. PL 1. 45. (1815) ; A. Brong. in Diet. 
Class. 3. 474. (1823) ; Grev. FI. Edin. xvii. (1824); DC. and Duby, 533. (1828) ; 
Hooker Brit. FI. 459. (1830). 
Essential Character. — Plants composed of an axis, consisting of parallel tubes, 
which are either transparent or encrusted with carbonate of lime, and of regular whorls of 
tubes, which may be either considered as leaves or branches. Organs of reproduction, 
round succulent globules, containing filaments and fluid ; aud axillary nucules, formed of 
a few short tubes, twisted spirally around a centre, which has the power of germinating. 
Affinities. The two genera of which this little order is composed are 
among the most obscure of the vegetable kingdom, in regard to the nature 
of their reproductive organs ; and accordingly we find them, under the com- 
mon name of Chara, placed by Linnaeus among Cryptogamous plants near 
Lichens; then referred by the same author to Phaenogamous plants, in 
Monoecia Monandria ; retained by Jussieu and De Candolle among Naiades, 
by Brown at the end of Hydrocharaceae, and by Leman in Halorageae ; 
referred to Confervae by Von Martins, Agardh,.and Wallroth ; and finally 
admitted as a distinct order, upon the proposition of Richard, by Kunth, De 
Candolle, Adolphe Brongniart, Greville, Hooker, and others. Such being the 
uncertainty about the place of these plants, it will be useful to give rather a 
detailed account of their structure, in which I avail myself chiefly of Ad. 
Brongniart’s remarks in the place above referred to, and of Agardh’s obser- 
vations in the Ann. des Sciences, 4. 61. I have not seen Professor Nees v. 
Esenbeck’s monograph of Characese in the Transactions of the Ratishon Society , 
quoted by the latter author. 
Characese are aquatic plants, found in stagnant fresh or salt water; 
always submersed, gmng out a fetid odour, and having a dull greenish 
colour. Their stems are regularly branched, brittle, and surrounded here and 
there by whorls of smaller branches. In Nitella the stem consists of a single 
transparent tube with transverse partitions, and, as Agardh remarks, so like 
the tubes of some Algae, as to ofihr a strong proof of the affinity of the orders. 
In Chara, properly so called, there is, in addition to this tube, many other 
external ones, much smaller, which only cease to cover the central tube 
towards the extremities. In the axillae of the uppermost whorls of these 
branchlets the organs of reproduction take their origin ; they are of two 
kinds, one called the nucule, the other the globule ; the former has been sup- 
posed to be the pistillum, the latter the anther. 
The nucule is described by Greville as being “ sessile, oval, solitary 
spirally striated, having a membranous covering, and the summit indis- 
tinctly cleft into 5 segments ; the interior is filled with minute sporules.” FI. 
Edinb. xvii. This is the general opinion entertained of its structure. But 
Brongniart describes it thus : — Capsule unilocular, monospermous ; pericarp 
composed of two envelopes : the outer membranous, transparent, very thin, 
terminated at the upper end by 5 spreading teeth; the inner hard, dry, 
opaque, formed of 5 narrow valves, twisted spirally.” Diet. Class. 1. c. He 
founds his opinion of the nucule containing but one germinating body upon 
the experiments of Vaucher, of Geneva, who ascertained that if ripe nucules 
of Chara, which have fallen naturally in the autumn, are kept through the 
winter in water, they will germinate about the end of April ; at that time a 
little body protrudes from the upper end between the 5 valves, and gradually 
gives birth to one whorl of branches, which produce a second. Below these 
whorls the stem swells, and little tufts of roots are emitted. The nucule 
adheres for a long time to the base of the stem, even when the latter has 
