WATER MILFOIL FAMILY 431 
white in a tall spike, each on a short foot-stalk. Damp woods. Com- 
mon. June-Aug. 
2. C. alpina, L. (Fig. 8, pl. 104.) SmMatiteR ENCHANTER’S NIGHT- 
SHADE. Plant, 3 to 8 in. high. The leaves heart-shaped at base, teeth 
more conspicuous than in No 1. Damp woods. July-Sept. 
Famity IV.—TRAPACEAE. Water-nut FAMILY 
Aquatic herbs, the submersed leaves of which are finely dis- 
sected, feather-formed, those which float are rounded and deeply 
indented. Of these last the leaf-stalks are inflated. Petals and 
sepals, each 4; stamens 4. Fruit a large spiny nut. 
1. TRAPA, L. 
Characteristics as above. 
T. natans, L. (Fig. 11, pl. 105.) Swimmine Water-nut. A large 
leaved aquatic, which has been introduced in lakes and parks and which 
has become naturalized in a few localities. June-July. 
FamMity V.—HALORAGIDACEAE. Water MixLrort FAMILY 
Our species all aquatic herbs. Calyx adherent to the ovary. 
Leaves in whorls or opposite, or rarely alternate, often finely dis- 
sected. Flowers with stamens and pistils or with those having one 
set of these organs on one plant and those with the other on an- 
other plant or with the two kinds of flowers on one plant. Petals 
small or none, when present 2 to 4. Stamens 1 to 8. Ovary 
oblong or cylindric, ribbed or angled. 
meaamen Pt ovary i-celled’. . : 5 . «.-s » « Hippuris 
Stamens 2 to 8; ovary 3- to 4-celled. 
Fruit sharply angled . . . . . +.  Proserpinaca 
Fruit splitting into 4 carpels . . . . Myriophyllum 
t. HIPPURIS: 
Stems erect, not branching. Leaves simple, without serrations, arranged 
in whorls. Flowers greenish, in the leaf axils, having a single stamen on 
the margin of the calyx and a single style, which is longer than the 
stamen. Petals absent. Fruit a small 1-celled drupe. 
H. vulgaris, L. (Fig. 1, pl. 105.) Mare’s Tam. Jornt WEEp. 
Plant, 1 to 2 ft. high. Leaves narrow linear, sharply pointed at the apex, 
attached directly to the stem at base where about 6 or more are arranged 
in a whorl. In borders of ponds and in marshes, in the northern part of 
our area. Flowers found all summer. 
z. PROSERPINACA, L. 
Aquatic; stems not generally branching, reclining at base, finally erect. 
