CONFERVOIDE^E. 



[ 201 ] 



CONIFERS. 



ULVACE^E. Marine or freshwater Algae, 

 consisting of membranous flat and expanded 

 tubular or saccate fronds composed of poly- 

 gonal cells firmly conjoined by their sides. 

 Reproduced by zoospores formed from the 

 cell-contents and breaking out from the 

 surface ; or by motionless spores f ormed from 

 the whole contents of a cell. 



PALMELLACE^E. Plants forming gela- 

 tinous or pulverulent crusts on damp sur- 

 faces of stone, wood, &c., or more or less 

 regular masses of gelatinous substance, or 

 delicate pseudo-membranous expansions or 

 fronds, of flat, globular, or tubular form, in 

 fresh water or on damp ground j composed 

 of one or many, sometimes innumerable, 

 cells with green, red, or yellowish contents, 

 spherical or elliptical form, the simplest 

 being isolated cells (found in groups of two, 

 four, eight, &c. in course of multiplication); 

 others permanently formed of some multiple 

 of four; the highest of compact, numerous, 

 more or less closely conjoined cells. Repro- 

 duction by cell-division ; by the conversion 

 of the cell -contents into zoospores ; and by 

 resting -spores, formed sometimes after con- 

 jugation, in other cases probably after 

 fecundation by spermatozoids. 



We shall include under the head of Pal- 

 mellacese, all those obscure Unicellular 

 Algte whose place is not at present satis- 

 factorily known. 



DESMIDIACEJE. Microscopic, gela- 

 tinous plants, of a green colour, growing in 

 fresh water ; composed of cells devoid of a 

 siliceous coat, of peculiar forms, such as 

 oval, crescentic, shortly cylindrical, or cylin- 

 dric-oblon^, &c., with variously-formed rays 

 or lobes, giving a more or less stellate form, 

 presenting a bilateral symmetry, the junc- 

 tion of the halves being marked by a division 

 of the green contents : the individual cells 

 either free, or arranged in linear series, col- 

 lected into faggot-like bundles, or in elegant 

 star-like groups, which are imbedded in a 

 common gelatinous coat. Reproduced by 

 division, and by resting -spores produced in 

 sporangia formed after the conjugation of 

 two cells and union of their contents ; and 

 by zoospores formed in the vegetative cells 

 (Pediastruni), or in the germinating resting- 

 spores. 



DIATOMACE^). Microscopic cellular 

 bodies, growing in fresh, brackish, and sea- 

 water; free or attached; single or imbedded 

 in gelatinous tubes ; the individual cells 

 (frustules) with yellowish or brownish, 

 rarely greenish, contents, and provided with 



a siliceous coat composed of two usually 

 symmetrical valves variously marked ; with 

 a connecting band or hoop at the suture. 

 Multiplied by longitudinal division ; and by 

 the formation of new larger individuals out 

 of the contents of conjugated cells ; perhaps 

 also by spores and zoospores. 



VOLVOCINE2E. Microscopic, cellular, 

 freshwater plants, composed of groups of 

 bodies resembling zoospores, connected into 

 a definite form by their enveloping mem- 

 branes. The plants (families) are formed 

 either of assemblages of coated zoospores 

 united in a definite form by the cohesion of 

 their membranes, or of assemblages of naked 

 zoospores enclosed in a large common in- 

 vesting membrane. The individual zoo- 

 spore-like bodies with two cilia throughout 

 life, perforating the membranous coats, and 

 by their conjoined action causing a free 

 movement of the entire group. Reproduc- 

 tion by division {Gonium)^ or by single 

 cells becoming converted into zoospores 

 which conjugate and form new families 

 (Pandorina, Volvox) ; and by resting-spores 

 formed from some of the cells after im- 

 pregnation by spermatozoids formed from 

 the contents of other cells of the same 

 family. 



BEBL. See the Families. 



CONIDTA. The name applied by Tries 

 to the stalked spores, stylogonidia, or repro- 

 ductive cells, produced directly from the 

 mycelium of many Fungi (PL 26. fig. 8) : 

 characteristic of the Coniomycetes. Late 

 discoveries have rendered the term of some- 

 what equivocal value; and it is not yet 

 sufficiently distinguished from STYLO- 

 SPORES and SPERMATIA. Physiologically, 

 thev are regarded as equivalent to the 

 gonidia of Lichens. 



CONIF'ER^E. A class of Gymnosper- 

 inous plants, so called from the peculiar 

 form of the female inflorescence, in which 

 the flowers are collected into imbricated 

 cones ; this is the case at least in the Abie- 

 tinese and Cupressineae : in the Taxinese, 

 which are separated by some authors, the 

 female flowers are solitary. These plants 

 are remarkable in many respects. The pro- 

 cesses occurring in the fertilization of the 

 ovules are quite different from those in the 

 Angiospermous flowering plants, and form 

 a link with the conditions in the higher 

 Flowerless plants. (See GYMNOSPERMIA.) 

 The pollen (PL 40. fig. 16) is of a remark- 

 able form in the Abietinese. The most 

 striking point, however, in relation to the 



