WATER-PLANTAIN FAMILY. 85 
1. Alisma Plantago-aquatica L,. 
Water Plantain. (Fig. 188.) 
Alisma Plantago-aquatica I,. Sp. Pl. 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 1/—10/ 
long; scapes occasionally 2 from the same 
root, usually solitary, 1%°-3° high; inflores- 
cence a large loose panicle, 6/-15’ long; 
pedicels verticillate in 3’s-10’s, subtended by 
3 striate acuminate bracts; petals 1%4//-1/’ 
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 1/’ 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 tenéllum Mart. Dwarf Water Plantain. (Fig. 189.) 
Alisma tenellum Mart.; R. & S. Syst. 7: 
1600. 1830. - 
Echinodorus parvulus Engelm. in A. 
Gray, Man. Ed. 2, 438. 1856. 
Echinodorus tenellus Buchenau, Abh. 
Nat. Gesell. Bremren, 2:18. 1869. 
Plant delicate, stoloniferous, 1/—5% 
high. Leaves lanceolate or linear- 
lanceolate, the blades acute at both 
ends, 4//-15/’ long, 1//-3// wide; 
petioles longer or shorter than the 
blades, narrowly dilated at the base; 
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 14// 
long, enclosed by the erect persistent 
sepals, the beak short, sharp. 
In mud, Massachusetts to western On- 
tario and Minnesota, south to Florida, 
Missouri and Texas. April-Aug. 
2. ECHINODORUS Rich.; Engelm. in A. Gray, Man. 460. 1848. 
Perennial or annual herbs with long-petioled, elliptic, ovate or lanceolate often cordate 
or sagittate leaves, 3-9-ribbed and mostly punctate with dots or lines. Scapes often longer 
than the leaves; inflorescence racemose or paniculate, the flowers verticillate, each verticil 
with 3 outer bracts and numerous inner bracteoles; flowers perfect ; sepals 3, distinct, per- 
sistent ; petals white, deciduous ; receptacle large, convex or globose ; stamens 12-30 ; ovaries 
numerous ; style obliquely apical, persistent; stigma simple; fruit achenes, more or less 
compressed, coriaceous, ribbed and beaked, forming spinose heads. [Grcek, in allusion to 
the spinose heads of fruit.] 
About 14 species, mostly natives of America. Only the following are known in North America. 
Scapes reclining or prostrate; style shorter than the ovary; beak of achene short. 1. 4. radicans. 
Scapes erect ; style longer than the ovary; beak of achene long. 
2. E. cordifolius. 
