512 TYPHACE.E. 



11. PISTIA, L. 



Spadix wholly adnate to the spathe, 2-flowered : upper flower <? , supported by a scutelli- 

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

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

 oo-2, parietal, " atropoas." Embryo in the summit of the albumen. — Floating, stoloniferous, 

 steniless herbs ; leaves rosular, palmatiuerved. 



Klotzsch regarded the scaly appeudage 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- 

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



26. P. occidentalis, Bl. Leaves obovate-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 many-seeded : seeds rugose. Jacq. 

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

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



12. LEMNA, L. 



Spadix reduced to a point : spathe membranaceous, rupturing -. flowers naked, <? 2, re- 

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

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

 flowens 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 "hemianatropous." — Frond 1 '"-2"' long. — Hab. Antigua!, 

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



28. 1m. trisulca, L. Fronds lanceolate-oblong, flat, the submersed connected in a 

 cross : root single ; flowers as in the preceding. — Fronds 3"'-l" long, the floating fertile 

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



13. WOLFFIA, Hork. 



Character of Lemna, but <J flower single, anther " simple, 2-valved," and the solitary 

 ovule atropous. — Floating, very minute, mostly rootless fronds ; flowers appearing on the 

 upper facet. 



29. W. punctata, Gr. (n. sp.) Fronds elliptical-oblong,/««wA on both sides, brown- 

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

 iii. 12. 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 \ -% 

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

 Jamaica !, Wullschl. 



CXXIX. TYPHACE^. 



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

 mule included. — Marsh plants ; leaves linear ; spadices unisexual, each supported by & 

 deciduous spathe. 



1. TYPHA, L. 



Flowers supported by scaly bristles or hairs, J monadelphous, 3-2(4-l)-androus, $ con- 

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

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

 1-2 deciduous spathes (besides the basilar), inferior $ : the ^.flowers supported by soft 

 hairs and abortive ovaries. 



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

 cave, 5"'-7t'" broad ; spadices jdistaut from each other, both cylindrical ; hairs in $ exceed- 



