258 



ALISMACEiE. 



Alisma. 



Group 2. Flowers not arranged on a spadix, furnished with a double perianth 

 consisting of calyx and corolla. Ovaries 3 — 6 or numerous, free, distinct or 

 more or less united. — Herbs, growing in water or in swamps. 



Order CX. ALISMACE^E. L. C. Rich. The Water-Plantain Tribe. 



Flowers regular, perfect or polygamous, furnished with distinct calyx and 

 corolla. Calyx of 3 sepals. Corolla 3-petalled. Stamens 6 - 12, or numer- 

 ous : anthers in the perfect flowers introrse. Ovaries numerous or rarely few, 

 one-celled, with one or rarely two campylotropous ovules in each : styles 

 distinct, persistent. Carpels usually distinct and crowded in a head, or dis- 

 posed in a circle, dry, 1-celled, indehiscent, mostly one-seeded. Embryo 

 curved like a horseshoe, without albumen. — Marsh or aquatic plants, with 

 fasciculate roots. Leaves radical, with long petioles which are sheathed at 

 the base, and a flat lamina. 



1. ALISMA. Linn.; Endl. gen. 1041. water PLANTAIN. 



[Said to be derived from the Celtic word alis, water ; which is its place of growth.] 



Flowers perfect. Sepals 3, green, persistent. Petals 3, deciduous ; the aestivation involute. 

 Stamens 6 (rarely more). Ovaries numerous, disposed in a circle, or crowded in a head : 

 stigmas simple. Carpels distinct, mucronate or awned with the persistent style. — Marsh 

 or aquatic plants, mostly stemless. Flowers pedicellate, usually in verticillate panicles or 

 racemes, white or rose-colored. 



1. Alisma Plantago, Linn. Common Water Plantain. 



Stemless ; leaves ovate or oblong, acute ; stamens 6 ; scape many-flowered, with compound 

 whorled branches ; carpels 12 - 20, obliquely obovate, obtuse. — Linn. sp. I. p. 342; Michx. 

 fl. 1. p. 218 ; Torr. ft. 1. p. 381 ; Bigel. fl. Bost. p. 144; Beck, hot. p. 378 ; Hook. ft. 

 Bor.-Am. 2. p. 68 ; Kunth, enum. 3. p. 148. A. trivialis & parviflora, Pursh, fl. I. p. 252; 

 Ell. sk. 1. p. 434. A. parviflora, Kunth, I. c. 



Root fibrous, perennial. Leaves all radical, on long petioles, mostly ovate and more or 

 less cordate at the base, 3-6 inches long, mostly 9-nerved ; the petiole longer than the 

 lamina. Scape 1-2 feet high, obtusely triangular, much branched in a verticillate manner, 

 with small ovate acuminate bracts at the divisions. Calyx much smaller than the corolla ; 

 the sepals ovate. Petals orbicular, usually white, but sometimes pale rose-color. Stamens 

 shorter than the corolla. Carpels arranged in a circle, and forming an obtusely triangular 

 truncate head. 



