84 



ALISMACEAE (WATER PLANTAIN FAMILY) 



* * Species of the interior ; teaf-bJades relatively large, sagittate with hroad 



tri'uigular auricles. 



2. L. calycinus (Engelm.) J. G. Sm. Taller (1.5-4 dm. high) ; leaf-blades 

 deeply sagittate, thin, 10-15-nerved, 4-8 cm. broad, the auricles triangular, 

 acute, nearly or quite as long as the terminal portion of the blade ; stipes re- 

 curving or procumbent, 1-4 dm. long, usually bearing 3-4 whorls of flowers ; 

 Head of carpels about 1 cm. in diameter. (Sagittaria Engelm.) — Muddy banks, 

 Mich, to Dak. and southw. 



Var. maximus (Engelm.) Robinson. Leaf-blades very large (3 dm. wide), 

 18-21-nerved, considerably broader than long, the auricles almost divaricaie ; 

 inflorescence stout, sometimes branched. {Sagittaria calycina, var. Engelm.^ 

 — O. {Moseley) and southw. 



a 



a 



42. 



Fl. 



E. tenellus. 

 X 1. b. Fr. xl. 



;. Acheue 3. 



3. ECHINODORUS Richard. 



Petals imbricated in the bud. Stamens 6-21 or more. — Mostly annuals, with 

 the habit of Sngittaria, the naked stems sparingly branched or simple, and the 



flowers on rather short pedicels, in whorls of 3-6 or more. 

 Fl. summer and autumn. (Name from exi-vdjb-qs, pinckly, 

 or from ex^vos, and dopos, a leathern bottle, applied to the 

 ovary, which is in most species armed with the persistent 

 style, so as to form a sort of prickly head of fruit. ) 



1. E. tenellus (Martins) Buchenau. >Scapes 1.5-10 cm. 

 high ; shoots often creeping and proliferous ; submersed 

 leaves lance-iinear phyllodia, emersed leaves petiolate with 

 a lanceolate blade, acute (1-3 cm. long) ; umbel single, 

 2-8-flowered ; pedicels reflexed in fruit ; flower 6 nun. 

 broad ; stamens 9 ; styles much shorter than the ovary ; 

 achenes beakless, 8-ribbed, reddish brown, without glands. 

 (Alisma Martins ; Helianthium Britton ; E. p^arvulus 

 Engelm.) — Submersed or on mud, e. Mass., Mich., Minn., and 

 southw. (S. A.) Fig. 42. k 



2. E. cordif51ius (L.) Griseb. Scape erect, 1-6 dm high, iM 



longer than the leaves ; leaves broadly ovate, cordate or truncate ^ 



at base, obtuse (the blade 2-11 cm. long) ; umbel proliferous, 

 in a branched panicle ; flower 8-10 mm. broad ; stamens 12 ; 

 styles longer than the ovary ; achenes with a conspicuous erect 

 beak. {E. rostratus Engelm.) — Borders of ponds and ditches. 111. to Kan., 



s. Cal., and Fla. Fig. 43. Var. lanceofAtus (Engelm.) 

 Mackenzie & Bush is a low form which has the leaves 

 lanceolate with an acute base. — 111., Mo. 



3. E. radicans (Nutt.) Engelm. Stems or scape prostrate, 

 creeping (6-12 dm. long), proliferous, bearing many whorls 

 of flowers ; leaves somewhat truncately heart-shaped, obtu.se 

 (5-20 cm. broad), long-petioled ; flowers 12-20 mm. broad; 

 stamens about 21 ; styles shorter than the ovary ; arhmes 

 with a short incurved beak, the keeled back denticulate. 

 — About ponds, etc., 111. to N. C. and Fla., w. to Kan. and 

 Tex. Fig. 44. 



48 E. cordifolius. 

 Acherie x 3. 



(I 



44. E. radicans. 



a. Fr. X 1. 

 b. Achene x 3. 



4. ALISMA L, Water Plantain 



Petals involute in the bud. Ovaries many in a simple circle on a flattened 

 receptacle, forming flattened coriaceous achenes, which are dilated and 2-3- 

 keeled on the back. — Scape with whorled panieled branches. Flowers small, 

 white or pale ro.se-color. (The Greek name ; of uncertain derivation.) 



1. A. Plantago-aquatica L. Perennial by a stout proliferous corm ; leaves 

 long-petioled, ovate or oblong, acute, mostly rounded or heart-shaped at base. 

 3-y-nerved ; scapes 1 or 2; pantcZe loose, pyramidal, 3-6 dm. long, much overtop- 



