678 ALISMACE Zé ALISMA 
with a very hard coat. In cold bogs, California to Alaska and across the 
continent: also in Europe and Asia. 
OrpER CVI ALISMACEAE DC. FI. France ii, 181. 
Marsh herbs with scape-like stems, broad leaves with sheath- 
ing base and conspicuous perfect or unisexual flowers in pani- 
cles orracemes. Perianth of 3 herbaceous persistent sepals and 
as many often conspicuous white deciduous sepals. Stamens 
6 or more, included. Ovaries numerous, distinct, 1-celled and 
_mostly 1-ovuled, becoming achenes in fruit. Seed erect, campy- 
lotropous, with membranous testa and no albumen. Embryo 
strongly recurved or uncinate. 
1 Alisma Flowers perfect: stamens usually 6: carpels numerous, ver- 
ticillate, distinct, obovate-oblong. 
2 Sagittaria Fowers monecious or diccious: carpels numerous, flat- 
tened and membranously winged. 
1 ALISMA L. Sp. 342. 
Perennial herbs growing in shallow water or mud with broad 
leaves and small flowers in a verticillately branched panicle. 
Flowers perfect, small, numerous, on unequal 3-bracteolate pedi- 
cels. Stamens 5, rarely more, with short filaments, Ovaries 
distinct, numerous, borne in several whorls on a small flat re- 
ceptacle, 1-ovuled. Styles very short, ventral. Achenes in a 
crowded whorl, ovate-oblong, flattened. 
A. Plantago-aquatica L. Sp. 342. Scapes %-3 feet high, usually 
solitary: leaves ovate, acute at the apex, cordate, rounded or narrowed at 
base, or when floating sometimes lanceolate or even linear, on petioles 1-10 
inches long: inflorescence a large loose panicle 5-15 inches long: pedicels 
verticillate in 3’s-10’s, subtended by 3 striate acuminate bracts: petals 44-1 
line long: styles deciduous, the base remaining as a small point or short 
beak on the inner curve of the achenes: stigmas small, terminal: achenes 
nearly 1 line long, arranged ina circle forming an obtusely triangular 
truncate head. In shallow water or mud, throughout North America: 
also in Europe and Asia. 
2 SAGITTARIA L, Sp. 993. 
Perennial aquatic or bog herbs with broadly sheathing leaves, 
often without blades, and mostly simple stems bearing one to few 
whorls of flowers mostly in threes. Flowers monoecious or some- 
times dioecious, the staminate ones above. Petals usually con- 
spicuous. Stamens usually numerous, inserted on the convex 
receptacle: anthers 2-celled, dehiscent by lateral slits. Pistillate 
flowers with numerous distinct ovaries. Stigmas small. Achenes 
numerous, densely aggregated in subglobose heads. 
S. arifolia Nutt. J. G. Smith Ann. Rep. Mo. Bot, Garden vii, 32. 
