26 



CHARACEyE. 



[Thallogens. 



ORDER V. CHARACEiE.— Charas. 



Characb^, Rich in Humb. et Bonpl. N. G. PL 1, 45. (1815) ; A. Brong. in Diet. Class. 3. 474. (1823) ; 

 Ch-ev. Fl. Edin. xvii. (1824) ; Endlich. Gen. iv. ; Schnitzl. ic— Chares, Kutzing, Phycologia, 

 p. 313. 

 Diagnosis. — Tuhular symmetrically branched bodies, multiplied by spiral-coated nucules, 



filled with starch. 

 Water plants composed of an axis, consisting of parallel tubes, which are either 

 transparent or encrusted with carbonate of lime, and of regular whorls of symmetrical 

 tubular branches. Organs of reproduction, lateral, round, succvdent, brick-red globules, 

 and axiUary nucules. The globules, consisting of triangular valves, enclosmg cen- 

 tripetal tubes and slender annular tlu^eads ; the nucules ha\'uig two coats, of which the 

 external is transparent and usually siu-mounted by five teeth ; the internal firm, 

 spirally-ribbed, filled with starch granules of vai'ious sizes. 



The genera of which this httle order is composed are among the most obscure of the 

 vegetable kmgdom, in regard to the natm-e of theu- reproductive organs ; and accord- 

 ingly we find them, mider the common name of Chara, placed 

 by Linnteus among Cryptogamous plants near Lichens ; then 

 refei-red by the same author to Phsenogamous plants, in ]\Ionoe- 

 cia Monandria ; retained by Jussieu and De CandoUe among 

 Naiads, by Brown at the end of Hydrocharacese, and by 

 Leman in Haloragese ; referred to Confervas by Von Martins, 

 Ao-ardh, and Walh'oth ; and finally admitted as a distinct order, 

 upon the proposition of Richard, by Kunth, De CandoUe, 

 Adolphe Brongniart, Gre^ille, Hooker, and others. Such being 

 the uncertainty about the place of these plants, it 

 will be useful to give a rather detailed account of 

 their structm-e, in which I avail myself chiefly of 

 Ad. Brongniart's remarks in the place above re- 

 ferred to, and of Agardh's observations in iheAnn. 

 des Sciences, 4. 61. 



Charas are aquatic plants, found in stagnant 

 fresh or salt water ; always submersed, giving out 

 a fetid odovir, and having a dull gi-eenish colour. 

 Theu' stems are regularly branched, brittle, and 

 surroiuided here and there by whorls of smaller 

 branches. In Nitella the stem consists of a single 

 transparent tube vdih transverse partitions ; Agardh 

 remarks that it is so like the tubes of some Algals, 

 as to offer 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 axils of the uppermost 

 whorls of these branchlets the organs of reproduc- 

 tion take then- origin ; they are of two kmds, one 

 called the nucule, the other the globule ; the former 

 has been supposed to be the pistil, the latter the 

 anther. 



The nucule is described by Greville as being 

 " sessile, oval, solitary, spirally striated, having a 

 membranous covering, and the summit indistinctly 

 cleft into five segments ; the mterior is filled ^Wth 

 minute sporules. FL Edin. xvii. Tliis is the ge- 

 neral opinion entertained of its structure. But 

 Brongniart describes it thus : — Capsule unilocular, 

 monospermous ; pericarp composed of two enve- 

 lopes : the outer membranous, transparent, very 

 Fig. XII. thin, terminated at the upper end by five spreading 



Fig. XII. — 1. Chara -sTilgaris ; 2. a portion of a branch with a nucule and globule ; 3. the globule more 

 magnified ; 4. the spiral tubes of the latter ; 5. a nucule cut open ; 6. a nucule in germination. 



