RIVER WEED FAMILY 295 
Fruit a rounded bur-like head. 
Tree with broad leaves and with fruit in globular 
heads hanging by long peduncles. Stamens and 
pistils in different flowers. Flowers without sepals 
or with minute ones. . . . . PLATANACEAE 
Fruit a legume, that is, a pod formed like that of a pea. 
Flowers slightly irregular, but not in form of a pea 
blossom. Stamen filaments united generally in 2 
GLOUPEee so 2 ae as +, 2 CARSALPINACKAT 
Flowers quite irregular, papilionaceous—having the 
general shape of a pea blossom PAPILIONACEAE 
Stamens more than 20 
Stamens all free. 
Fruit, follicles or achenes, 1. e., dry one-celled seed vessels with 
several seeds, or a dry vessel with a single seed ROSACEAE 
Fruit a drupe, v. ¢., like a plum or cherry, with a fleshy exte- 
rior and woody stone within. . . . . . DRUPACEAE 
Fruit a pome, 1. e., a fleshy fruit like the apple or pear 
POMACEAE 
(In the Hawthorns, Mountain Ash and Shad-berry the fruit 
is small and less fleshy than the pear and apple.) 
Famity I.—PODOSTEMACEAE. River Weep FaAmity 
Only a single species in our region. A fresh water submersed 
plant with the general appearance of the Naiads. ‘The leaves are 
thread-formed, much divided. Flowers without perianth except 
a small spathe-like envelope at base of the very simple flower 
which consists of the ovary and of a rather long stamen filament 
dividing toward the top into two stamens. 
PODOSTEMON, Michx. 
Characters as above. 
1. P. ceratophyllum, Michx. (Fig. 1, pl, 59.) River WEED, THREAD 
Foot. Plant submersed, dark green with thread-like leaves forming 
dense fascicles. Flowers very small, inconspicuous, at axils of leaf 
branches. In shallow streams, northern New York and _ southward 
throughout the range. July-Sept. 
