500 ONAGRACEAE. 
2. Circaea alpina IL. Smaller 
Enchanter’s Nightshade. 
(Fig. 2611.) 
Circaea alpina J, Sp. Pl. 9. 1753. 
Smaller, 3/-8’ high, simple or branched, weak, 
glabrate, or pubescent above. Leaves ovate, 
slender-petioled, acute or acuminate at the 
apex, more or less cordate at the base, coarsely 
dentate, 1/-2’ long; flowers about 1/’ broad; 
pedicels 114’/-2’’ long, reflexed in fruit; fruit 
narrowly obovoid, about 1// long, covered with 
weak soft hooked hairs. 
In cold moist woods, Labrador to Alaska, south 
to Georgia, Indiana, Michigan and Minnesota. 
Also in Europe and Asia. Leaves thin, somewhat 
shining. Ascends to 6300 ft. in North Carolina. 
July-Sept. 
Family 88. TRAPACEAE Dumort, Fl. Belg. go. 1827. 
WATER-NUT FAMILY. 
Aquatic herbs, with opposite pinnatifid submerged leaves, and clustered 
rhombic-ovate dentate floating ones with inflated petioles. Flowers perfect, 
axillary, solitary, short-peduncled. Calyx-tube short, the limb 4-parted, the 
lobes persistent. Petals 4, sessile, inserted on the perigynous disk. Stamens 
4, inserted with the petals; filaments subulate-filiform. Ovary 2-celled, conic 
above; style subulate; ovule 1 in each cavity. Fruit coriaceous or bony, large, 
See or swollen at the middle, 1-celled, 1-seeded, indehiscent. Seed in- 
verted. 
A single genus of 3 species, natives of Europe, tropical Asia and Africa. 
ty RAPA Ta Speblemizous 9753: 
Characters of the family. [Latin, from Calcitrapa, the Caltrop. ] 
1. Trapa natans L. Swimming 
Water-nut. Water-Chestnut. 
Water-Caltrop. (Fig. 2612.) 
Trapa naians I,. Sp. Pl. 120. 1753. 
Rooting in the mud at the bottom of lakes 
or slow streams; stem often several feet long. 
Submerged leaves approximate, pectinately 
dissected, 1/-4’ long; floating leaves in a 
rosette sometimes 1° broad, their blades 
rhombic-ovate, sharply dentate above, broad- 
ly cuneate and entire below, about 1/ wide, 
glabrous and shining above, the conspicuous 
veins of the lower surface beset with short 
stiff hairs; petioles of the floating leaves 2’— 
6’ long, inflated and spongy; flowers white, 
about 3/” broad; fruit 1/-2’ long, armed with 
4 somewhat recurved spines. 
Naturalized in ponds, eastern Massachusetts, 
and near Schenectady, N.Y. Native of Europe. 
Called also Sanghara-nut. Seed mealy, edible. 
June-July. 
Family 89. HALORAGIDACEAE Kl. & Garcke, Bot. Erg. Wald. 151. 1852. 
WATER-MILFOIL FAMILY. 
Perennial or rarely annual herbs, mainly aquatic, with alternate or verticil- 
late leaves, the submerged ones often pectinate-pinnatifid. Flowers perfect, or 
monoecious, or dioecious, axillary, in interrupted spikes, solitary or clustered. 
