104 ALISMACEAE 
2. A. tenellum, Mart. Dwarr WatTER PLANTAIN. (Helianthium 
tenellum, Britton. Hchinodorus tennellus, Buchenau.) Leaves lance- 
shaped, on long leaf-stalks all basal. Flower stem naked, bearing at 
summit a spreading whorl or umbel of 2 to 8 white flowers on unequal 
flower stalks. Muddy places. Mass. southward and westward. April- 
August. 
3. A. Geyeri, Torr. Leaves linear-lance-shaped to elliptic, overtop- 
ping the shorter flower scapes. Whorls of flowers several, the cluster 
more diffuse than that of No. 1. Individual flower stems thick, strongly 
divergent in fruit. Petals rose color at the margins with a yellow spot 
at base. Locally, N. Y. and westward. 
2. LOPHOTOCARPUS, Durand 
Aquatic herbs with leaves and flowers resembling sagittaria and hardly 
distinguished from it. In this genus the flowers are all perfect, 7. e,, 
stamens and pistils are on the same receptacle. In sagittaria the stamens 
and pistils are in different flowers. 
l. L. calycinus, J. G. Smith. Lopnotocarpus. Leaves lance-arrow 
or halberd-shaped. Flower stem decumbent. Plants with habits and ap- 
pearance of sagittaria. Swamps and muddy bottoms, our area. July- 
September. 
2. L. spongiosus, (Engelm.) J. G. Smith. Sponey SaGIrraria. 
Submersed aquatic with thick spongy stem-like leaves which are 4 to 12 
in. high, sometimes expanding to an arrow-shaped leaf-blade, 2 to 4 in. 
long, with or without diverging acute lobes half as long as the leaf-stalks, 
at length decumbent. New Brunswick south to Virginia. July-August. 
3. L. spathulatus, J. G. Smith. SpATULA-LEAVED SAGITTARIA. Small 
aquatie with stem-like leaves, without leaf-blades. These bladeless leaves 
1 to 24 in. high. Flower stem usually shorter than the leaves, 1 or 2 
flowered. Stamens 6 to 9. On sandy beaches within influence of the tide. 
Newburyport, Mass. 
3. SAGITTARIA, L. 
Water plants growing in muddy borders of ponds and streams. Leaves 
and flowers aerial. Leaves all at base, varying from the extreme arrow- 
head form to long lance-shape or even to long leaf stalks without blade. 
Flowers on a spike in whorls of 3’s, each whorl subtended by a whorl of 
3 bracts; upper flower whorls consisting of staminate, the lower of 
pistillate flowers. Corolla of 3 broad white petals, calyx of 3 green 
sepals. Carpels on a convex receptacle. The beak at the extremity of the 
carpel forms an important feature for identification of some variable 
species. 
Leaves arrow-shaped (sagittate), with the posterior lobes at least } as long as the 
blade. 
Bracts below the pistillate (lower) flowers as long as the individual flower stems. 
Beak at extremity of fruit more than } the length of the fruit 
itself . Jeera ewe as la? 9:8. hele Set OR BSROS Ent 
3eak less than } length of frait oF ain - « SO» anifoka 
Bracts below pistillate flowers shorter than the flower stems. 
Leaves broad a. bal ot. at te ous GRE ROIREE 
Leaves very narrow, not always | arrow- -shaped « « » »« &, EBagelmannia 
