ALISMACEJE, (WATER-PLANTAIN FAMILY.) 447 
impressed-nerved, longer than the filiform petioles ; immersed leaves filiform, 
scattered ; spikes oval or oblong, short-peduncled ; achenium nearly circular, 
concave on the sides, rugose or tuberculate, and 1 -8-ridged on the back; 
embryo coiled. (P. setaceus, Pursh. P. heterophyllus, ÆU. ?) — Shallow ponds, 
Florida, and northward. June - Aug. — Floating leaves 6-8! long, com- 
monly 5-nerved. 
Orper 139. ALISMACEJE. (WaTER-PLANTAIN Famity.) 
Marsh herbs, usually with creeping runners or rootstocks, nerved and 
reticulated sheathing leaves, and scape-like stems, bearing the perfect or 
moneecious flowers in spikes or whorled racemes. — Sepals and petals 3, 
or the latter sometimes wanting. Stamens few or numerous: anthers 2- 
celled. Ovaries 3 or many, with 1-2 anatropous or campylotropous erect 
ovules. Style short or none. Achenium coriaceous, 1—2-seeded. Em- 
bryo straight or curved, without albumen. 
Synopsis. 
Sunorper I. JUNCAGINEJE. Sepals and petals (when present) 
greenish. Ovule anatropous. Embryo straight. Ete os Titra: 
l TRIGLOCHIN. Leaves rush-like. Flowers in spiked racemes. 
Susorper II. ALISMEZE. Petals white, deciduous. Ovule cam- 
pylotropous. Embryo curved or hooked. 
2. ALISMA. Flowers perfect. Achenia whorled. Racemes compound. 
8. ECHINODORUS. Flowers perfect. Achenia clustered in a head. 
4. SAGITTARIA. Flowers moncecious. Achenia clustered in a head. 
1, TRIGLOCHIN, L. 
Flowers perfect, in a spiked raceme. Sepals 3. Petals 3, and greenish, like 
the sepals, or none. Anthers 3-6, nearly sessile, oval. Ovaries 3-6, united 
around a central axis, from which they separate at maturity, l-ovuled. Stigmas 
plumose. Embryo straight.— Leaves rush-like, fleshy, 2-ranked. Flowers 
small, bractless. 
1. T. triandrum, Michx. Leaves erect, linear-subulate, semi-tercte, di- 
lated at the base and sheathing the base of the terete scape; flowers very numer- 
‘us, on short pedicels; sepals oval, deciduous ; petals none; anthers and ovaries 
3; fruit globose-triangular, pointless, when dry 3-winged by the compressed 
Stibbed achenia; embryo oblong. — Salt marshes along the coast, West Florida 
fo North Carolina, Aug.-Sept.— Scape and leaves 39 + 19 high. 
2. ALISMA, L. WarEn-PrANTAIN. Hs 3 
, Flowers perfect in a whorled panicle. Sepals 3. Petals 3, involute in the 
bud, deciduous. Stamens 6-12. Ovaries numerous in a simple whorl. Siyle 
