FRESH-WATER A L G uE OF THE UNITED STATES. 203 



personiiUy, and as bfing among the foremost students of American phanerogamic 

 ■botany. 



This species is more nearly allied to S. minor than to any other of the European 

 I forms, but differs from it very essentially in size and habit. It is always, as I have 

 'seen it, except in very young plants, sparsely and mostly dichotomously branched, 

 and attains a very great length, at times probably exceeding the third of an incli. 

 The spore is mostly sessile upon the distal ends of the cells of the filament ; in all 

 such cases I have noticed that the cell upon which it was borne was divided in its 

 ■ middle by a partition into two cells. Not unfrequently the spore is raised upon a 

 short branch. The male plants are attached to the female filaments generally in 

 the neighborhood of the sporangium, to which they sometimes fasten themselves 

 immediately. They are shortly stipitate, and composed of two cells. The mature 

 spore is transversely oval, now and then slightly triangular, and is nearly of the 

 ; color of burnt sienna. Its .coat is thick, often slightly yellowish, and has on its 

 : outer surface irregular punctations, looking like corrosions. These are not detach- 

 able, except when the ruptured spore is more or less completely emptied of its 

 contents. The sporangium closely invests the spore, and when the latter is matured 

 undergoes a circular division, so that the top falls ofi" and allows the spore to escape. 

 Fig. 6 c, pi. 16, represents a portion of a filament, magnified 260 diameters, 

 j with a young sporangium and young male plants attached ; 6 b, represents a very 

 ' young plant, magnified 260 diameters. Fig. 6 a, was taken from a mature plant, 

 and shows the mature spore. Fig. 6 e, shows in outline a sporangium and male 

 plants attached ; whilst 6 d, was drawn from a sporangium which had perfected 

 its spore and undergone the natural dehiscence. 



Family CHEOOLEPIDE^. 



Algae aercce, aureo-, aurantiaco- vel rubro-fusco-colorata3, siccatas soepe cante. Fila Tarie raraosa, 



eytioderraato crasso vel subcrasso, firmo, subcartilagiiieo pi'«dita, in pulvinulos raiiiutos vel iu stra- 



: turn tenue aut incrassato-tomentosum densissime aggregata vel implieata. Cytioplasnia oleosum vel 



' granulusum, aut rubellum, aureum, aut flavo-fuscum, intei-dum viride tinctuui, post mortem plerum- 



que expallescens. Propagatio fit zoogouidiis. 



^Ei-ial algae. Golden orange, or reddish fuscous, often grayish when dried. Filaments variously 



branched, furnished with a tliiek, or thiekish, subcartilagiuous cytioderm, densely aggregated into 



minute cushions, or a thin or tomentosely thickened stratum. C'ytioplasm granular or containing 



: oily particles, reddish-golden, or yellowish-fuscous, sometimes tinged with green; after death often 



colorless or nearly so. Propagation by zoospores. 



Remarks. — The plants of this family are so diff"erent from the others of the 

 order, that it is a matter of considerable doubt whether or not they should be 

 classified with them. They rarely possess distinct, well-pronounced chlorophyl, 



; and form mats or strata of some shade of reddish, grayish, or brownish, so that 

 tlicy are very different in appearance from the other Confei-vacece. 



! I do not think their position can be certainly fixed until tlieir life-history has 



; been more fully developed. In assigning them this place I have simply followed 



I Prof. Rabenhorst. 



