512 LYCOPODIACE^. Selaginella. 



2. p. 654 ; Torr. compend. p. 359 ; Hook. ^- Greu. I. c. p. 174 ; Beck, hot. p. 461 ; 

 Darling:, jl. Cest. p. 589. L. albidulurn, Hook. ^ Grev. I. c. (in part) ; Pursh, I. c. 



Annual ? Stems numerous, moss-like, 1 - 4 inches long, with somewhat pinnated flattened 

 branches, throwing down rooting fibres from the forks on the underside. Leaves scarcely 

 more than a line long, pale green, minutely denticulate as seen under a lens, membranaceous, 

 rather obtuse or somewhat acute ; those of the lateral rows spreading horizontally, a little 

 clasping : intermediate ones ovate, acuminate. Spikes terminating the branches, sessile, 2-4 

 lines long : bracts resembling the leaves, except that the upper ones are smaller and more 

 acute. Oophoridia chiefly occupying the lower part of the spike, tumid, conspicuous : grains 

 3-4, roundish, yellowish while, opening by 2 nearly equal valves ; the surface marked with 

 minute reticulated wrinkles. Anlheridia much smaller, oval, erect, filled with saffron-colored 

 sporidia or dust. 



Moist shady woods : frequent. Fr. July - August. Resembles S. Helvetica of Europe ; 

 but in that species the spikes are elongated, and the fructiferous scales small and rather distant. 



Order CXXIX. SALVINIACEiE. Bartl. The Salvinia Tribe. 



Fructification of two kinds on the same plant, situated at the base of the leaves 

 or on leafless submerged branches. Involucres globose, closed, without valves 

 or opening transversely : one kind filled with numerous or solitary angular or 

 globose bodies (antheridia? ), 1 - 2-celled ; the other one-celled, including 

 pedicellate saccules or capsules, which contain spores or grains. — Stems 

 swimming and rooting. Leaves alternate, sessile, entire, imbricated, papillose 

 or with fascicled short bristles above. 



1. SALVINIA. Micheli ; Bisch. in nov. act. nat. cur. 14. p. 45. t. 4, 5. salvinia. 



[In honor of Saltini, an Italian professor.] 

 Antheridia? spherical, attached to a pencillate central receptacle. Capsules or saccules 

 several, subglobose, attached to the summit of a clavate pedicel. — Very small aquatic 

 plants. Stem floating, filiform. Fructification glomerated on submerged leafless branches. 



1. Salvinia natans, Willd. Floating Salvinia. 



Leaves elliptical, obtuse, somewhat cordate at the base, with fascicles of hairs above. — 

 Willd. sp. 5. p. 541 ; Pursh, Jl. 2. p. 672 ; Beck, hot. p. 462. 



Floating like Lemna, on the waters of small lakes in the western parts of New- York 

 (^Pursh). I have seen no North American specimens of this plant. 



