512 TYPHACEJ!. 



11. PISTIA, L. 



Spadix wholly adnats to the spathe, 3-flowered : upper flower S . supported hy a scntelli- 

 form disk, inferior $ , laterally adnate to the spadix, separated from (? by a scaly appendage. 

 Anthers 3-8(-2), adnate to au entire column : cells 4, in a cross. Ovary 1-celled : .ovules 

 .00-2, parietal, " atropous." Embryo in the summit of the albumen. — Floating, stoloniferous, 

 stemless herbs ; leaves rosular, palmatinerved. 



Klptzsch regarded the scaly appendage and the disk as perigonial organs, but the former 

 is apparently homologous to the (stipular ?) dissepiment or stricture of the spathe occurring 

 in Ambrosinia. The number of stamens, upon which he chiefly constituted his genus Lim- 

 honesis, is, as Swartz observed, variable in our species from 3 to 8. 



26. P. occidentalis, Bl. Leaves i)bovate-rhomboid, truncate-rounded or emarginate 

 at the top, broadly sessile, 7-13-nerved ; spathe whitish: peduncle short, " scaly appendage 

 2-partite .- segments diverging ;" anthers 3-8 ; berry inany-seeded : seeds rugose. — Jacj. 

 Amer. fief. t. 225. — P. stratiotes, Jacq., Sw. — Leaves 2"-6" diam. — Hab. Jamaica !, M'Nai, 

 common in ponds ; Antigua !, WvilscU. ; [Cuba to French islands !, and Florida to Brazil]. 



12. LEMNA, i. 



Spadix reduced to a point : spathe membranaceous, rupturing : flowers naked, S 2, re- 

 duced to sibgle stamens, contiguous to the single ? . Anthers didymous. Ovary 1-celled : 

 ovules anatropous or hemiauatropous. Pericarp utricular. — Floating, small, rooted fronds ; 

 Bowers rarely appearing in a marginal cleft of the frond. 



27. I>. minor, L. Fronds roundish-obovate, flattish beneath : root single : filaments fili- 

 form; ovary 1-ovulate: ovule "hemiauatropous." — Frond l"'-2"' long. — Hab. Antigua!, 

 WullscAl.; [both temperate and tropical zones, in ponds]. 



28. It. trisulca, L. Fronds lanceolate-oblong, flat, the submersed connected in a 

 cross ; root single ; flowers as iu the preceding. — Fronds 3"'-l" long, the floating fei-tile 

 ones smaller. — Hab. Antigua !, Wullschl. ; [both temperate and tropfeal zonds, in ponds]. 



13. WOLFFIA, ffork. 



Character of lemna, but S flower single, anther " simple, 2-valved," and the solitary 

 ovule atropous. — Floating, very minute, mostly rootless fronds ; flowers appearing on t/ie 

 upperfacet. 



29. W. punctata, Or. («. q>.) Fronds eIliptical-oblong,/a<feA on both sides, irnwn- 

 dotted: single cleft not margined. — Nearly allied to W. brasiliensis, Wedd. (Ann. Sc. Nat. 

 iii. 13. t. 8), but distinguished from its figure by the fronds twice as long as broad, not he- 

 mispherical beneath, and the utricle (seen only once) ellipsoidal, not globose. Fronds \'"-k"' 

 long, dotted on both sides : two or several generations of fronds usually cohering. — Hab. 

 Jamaica I, Wullschl. 



CXXIX. TYPHACEiE. 



Character of Aroideai, but spadices 2 or several, one above the other, fruit dry, and plu- 

 mule included. — Marsh plants; leaves linear ^ spadices K«wejT<a/, each supported by a 

 deciduous spathe. 



1. TYPHA, L, 



Flowers supported by scaly bristles or hairs, S monadelphous, 3-2(4-l)-aodi-ous, ? con- 

 sisting of simple stipitate ovaries, which contain a single, hanging, anatropous ovule. Gary- 

 opsis long-stipitate : epicarp splitting.— Spadices 2, superior <? , cylindrical, interrupted by 

 1-2 dedduoUs spaihes (besides the basilar), inferior % : the ^flowers supported by soft 

 hairs and abortive ovaries. 



1. T. aneustifolia, L., var. domingensis, Pers. Leaves flat or slightly convex-con- 

 cave, 5"'-74"' broad ; spadices distant from each other, both cylindrical ;'hairs in (J exceed- 



