WATER-PLANTAIN FAMILY 



i. Alisma Plantago-aquatica L,. 

 Water Plantain. (Fig. 1 88.) 



Alisma Plantago-aquatica L. Sp. PI. 342. 1753. 



Leaves ovate, acute at the apex, cordate, 

 rounded or narrowed at the base, the blades 

 3-io-ribbed, or when floating sometimes 

 lanceolate or even linear ; petioles I'-ic/ 

 long ; scapes occasionally 2 from the same 

 root, usually solitary, ^-3 high ; inflores- 

 cence a large loose panicle, 6 / -i5 / long; 

 pedicels verticillate in 3's-io's, subtended by 

 3 striate acuminate bracts ; petals yi"-\" 

 long ; styles deciduous, the base remaining as 

 a small point or short beak on the inner 

 curve of the achene ; stigma small, terminal; 

 achenes obliquely obovate, nearly \" long, 

 arranged in a circle, forming an obtusely 

 triangular truncate head. 



In shallow water or mud throughout North 

 America. Also in Europe and Asia. June-Sept. 



2. Alisma tenellum Mart. Dwarf Water Plantain. (Fig. 189.) 



Alisma tenellum Mart.; R & S. Sjrt. 7: 



1600. 1830. 

 Echinodorus parrulus Engrlm 



Gray, Man. Kl .\ 4$. 1856. 

 Echinodorus tenellus Buchcnau. Abh 



Nat. Gesell. Bremen, 3: 18. 18691 



Plant delicate, stolon iferous, 1'-$' 

 high. Leaves lanceolate or linear - 

 lanceolate, the blades acute at both 

 ends, 4"-i5" long, i"-3" wide; 

 petioles longer or shorter than the 

 blades, narrowly dilated at the bate; 

 scapes solitary, often surpassing the 

 leaves, commonly reclined; umbel 

 2-8-flowered ; pedicels very unequal, 

 often recurved in fruit ; bracts lanceo- 

 late, more or less connate at the base; 

 flowers white ; stamens 9 ; style much 

 shorter than the ovary ; ovaries nu- 

 merous; achenes in several whorls, 

 coriaceous, turgid, obovate, not ft" 

 long, enclosed by the erect {JLililtHt 

 sepals, the beak short, sharp. 



In mud, Massachusetts to wcntcrn On 

 tario and Minnesota, sooth to Florida, 

 Missouri and Trxas. April- Aug. 



2. ECHINODORUS Rich.; Engelm. in A. Gray, Man. 460, 

 Perennial or annual herbs with long-petioled, elliptic, ovate or lanceolate oAe 

 or sagittate leaves, 3-a,-ribbed and mostly punctate with dots or lines, 

 than the leaves ; inflorescence racemose or paniculate, the flowers vertic 

 with 3 outer bracts and numerous inner bracteoles ; flowers perfect ; sepals 

 sistent ; petals white, deciduous ; receptacle large, convex or globose ; stamens it- 

 numerous ; style obliquely apical, persistent ; stigma simple ; fruit ach 

 compressed, coriaceous, ribbed and beaked, forming spinose heads. 

 the spinose heads of fruit.] 



About 14 species, mostly natives of America. Only the following arc known in X 

 Scapes reclining or prostrate; style shorter than the ovary; beak of achene short. 

 Scapes erect ; style longer than the ovary; beak of achene Ion*. 



