14 



CONFERVACEiE. 



[AlQALS. 



Order II. CONFERVACE^.— Confervas. 



Confervncea:, Endl. gen. Suppl. III., p. 10. Zoospermeae ,J. Aph. fig. Med. 

 and Zoospermeas, Dccaisne in Ann. be. If. i ser. 18. dvt>. 



1 . Syr\sT>or''a> 



Diagnosis. Vesicular, filamentary or membrartous bodies, multiplied by oospores 



generated in the interior, at the expense of their green matter. 



Water plants, not commonly of a green colour, but occasionally olive, violet, and red ; 

 inhabiting the ocean in some instances, but more commonly found in fresh water ; some 

 of them even belonging to both kinds of fluids; some found in 

 mud, others floating freely, most attached, in some way, on rocks 

 or as parasites. Cells solitary or many, globose, elliptical, 

 cylindrical, or tubular ; sometimes variously branched ; some- 

 times formed in slimy matter in which they are scattered, or 

 irregularly heaped, or placed one above the other in a regular 

 series forming an articulated frond ; some disposed in several 

 rows and forming a thin layer, or some combined in the form 

 of a net. Their mode of growth by a subdivision of the cells, 

 of ramification by a lateral extension of such cells, a dividing 

 partition being eventually formed. The propagatimi by sporidia 

 (internal cells, or a gelatinous substance which organizes itself 

 into cells,) found in each cell, singly, or in a definite, or indefi- 

 nite number, formed from the colouring matter of one or more 

 cells, or sometimes by the copulation of distinct individuals, and 

 discharged by the opening or absorption of the mother cell. — 

 Endl. 



If doubts exist as to the Vegetable nature of the last order, 

 or of some part of it, no question arises as to what that of 

 Confervas is. Its genera are now admitted on all hands to 

 be plants, since M. Decaisne's important discovery of the vege- 

 table nature of several things which had been previously 

 regarded as Zoophytes. Nevertheless, it is curious to see how 

 much, at one period at least of their existence, they have of an 

 animal nature, if the power of moving from place to place is to 

 be taken as an indication of such a quality. It seems incon- 

 testable, notwithstanding the denial of Mohl and others, that 

 many of the Conferva tribe, especially of the genera Conferva, 

 Ulva, and their near allies, produce in their tubular threads 

 reproductive bodies, or spores, which after a time acquire a 

 power of rapid, and quasi-voluntary motion while in the inside 

 of their mother ; that by degrees, and in consequence of their 

 constantly tapping against the soft side of the cell that holds 

 them, they escape into the water ; that when there they swim 

 about actively, just like animalcules ; and at last retreating to a shady place, attach 

 themselves to a stone or some other body, lose their locomotive quality, and thence- 

 forward germinate and grow like plants. — (/. Ag. Ann. Sc. Nat. 2 ser. vol. 6.)* It is 



* " The filaments of Conferva aerea," says the younger Agardh, "are, as is well known, articulated or 

 divided nt equal distances into little compartments I joints), which have no communication among them- 

 other than what results from the permeahility of the dissepiments. The green matter contained 

 in these joints appears at first altogether homogeneous, as if it were fluid ; but in a more advanced state 

 it becomes more and more granular. The granules are, at their formation, found adhering to the inner 

 surface of the membrane, but they soon detach themselves, and the irregular figure which they present at 

 first passes to that of a sphere. These granules congregate by degrees in the middle of the joint, into a 

 mass, nt first elliptical, but which at length becomes perfectly spherical. All these changes are conform- 

 able to phenomena known in vegetable life ; those which are to follow have more analogy with the pheno- 

 mena of animal life. At this stage an important metamorphosis exhibits itself, by amotion of swarming 

 nn niiiuvemeut de founnillement) in the green matter. The granules of which it is composed detach 

 themselves from the mass . one after another, and having thus become free, they move about in the vacant 

 space of the joint with an extreme rapidity. At the same time, the exterior membrane of the joint is 

 observed to swell in one point, till it there forms a little mammilla, which is to become the point from which 

 the moving granules finally issue. Ry the extension of the membrane for the formation of the mammilla, 

 the tender fibres of which it is composed separating, cause an opening at the end of the mammilla, and it 



Fig. III. 



Fiir. 111.- 1. Protococcus viridis ; 2. the same beginning to develop ; 3. the same more advanced ; 4 A 

 5. ScnUogoninm morale; 6. A fragment of Diva (l'rasiolat furfuracea (Kittzing). 



