460 ALISMACEJ2. (WATER-PLANTAIN FAMILY.) 
flattened coriaceous achenia in fruit. — Roots fibrous. Leaves all 
from the root, several-ribbed, with connected veinlets. Scape with 
whorled panicled branches. Flowers small, white or pale rose- 
color. (Name from dXvoyids, anxiety , from the supposed reme¬ 
dial properties.) 
1. A* Plants* go, L. Leaves long-petioled, ovate, oblong, or 
lanceolate, pointed, either narrowed, rounded, or somewhat heart- 
shaped at the base, 3-9-nerved; panicle loose, compound, many- 
flowered; carpels 15-20, obliquely obovate, forming an obtusely 
triangular whorl in fruit, lj. (A. trivi&lis and parviflora, Pursh .) — 
Ditches and marshy places, common. July, Aug. — Scape l°-2° 
high. A variable plant: the flowers perhaps generally smaller and 
the thread-like pedicels longer than in the European form. 
4. ECIIINODORUS, Richard, Engelmann. 
Flowers perfect. Petals imbricated in the bud. Stamens (6? -) 
7-21. Ovaries several or many, crowded without order in a 
head, forming achenia in fruit, often beaked with a projecting per¬ 
sistent style.—Habit intermediate between the preceding genus 
and the following. (Name apparently from ixivabr]*, prickly , or 
from ixivosj and bopos , 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.) — I adopt this restituted ge¬ 
nus from Dr. Engelmann’s MSS. E. rostratus, Engelm. (Alisma, 
Nutt .), and E. radicans, Engelm. (Sagittaria, Nutt.), are South¬ 
ern species : the former also grows in Illinois. 
1. E. SllblllatllS, Engelm. Annual, small ; primary or im* 
mersed leaves linear, the others with a distinct linear-lanceolate or 
oval-lanceolate blade acute at both ends; scapes about the length of 
the leaves, umbellately few- (3-8-) flowered, some of them becoming 
proliferous runners ; pedicels elongated, recurved in fruit; petals in¬ 
versely heart-shaped; stamens about 9; styles very much shorter 
than the ovaries; achenia rounded-half-obovate, acutely 3-ridged on 
the back, pointless. (Alisma subul&ta, L., Pursh Sagittaria pusilla, 
Nutt. ; but of this I am doubtful, as that is said to be monoecious.) ' 
Muddy margins of ponds and streams, from New York, Penn., nnd 
Michigan southward. Aug. —Plant l'-3' high, ripening 8-15 car¬ 
pels in each flower. 
5 . SAGITTARIA, L. Arrowhead. 
Flowers monoecious, rarely dioecious. Petals imbricated in the 
bud. Stamens many. Ovaries many, collected without order in 
