570 DIOECIA POLYAXDRIA 



Order 8. Emu andria. 



455. UDORA. JYutt. Gen. 800. 

 [Greek, Hydor } or Udor, water ; from its place of growth] 



Spaihc bifid, 1 -flowered. Perianth 6-parted, the 3 inner segments pe- 

 taloid. Staminate Fl. Stamens 9, 3 of them interior. Pistillatk 

 Vl. Tube of the perianth very long and slender. Sterile filaments 3. 

 Utriculus about 3-seeded. Seeds cylindric. 



Herbaceous aquatics : submersed and floating, with the roots 6xed ; leaves en- 

 tire, verticillate in threes or fours ; flowers axillary, solitary. Nat. Ord. 231. Lindl. 

 Hydrochaiude.e. 



1. U. canadensis, JVutt. Leaves mostly verticillate in threes, ellip- 

 tic-oblong and lance-linear, rather acute, very minutely serrulate ; tube 

 of the perianth filiform. Beck, Hot. p. 342. 



Elodea canadensis. Mx. Jim. 1. p. 20. Torr. Comp. p. 376. Not 

 Elodea of Pursh. 



Serpicula verticillata. Muhl. Catal. p. 84 Not of WUUU Pets. Ac. 

 8. occidentalis. Pursh, Am. I. p. 33. 

 8. canadensis. Eat. Man. p. 336. 



Canadian Udoha. 



Root perennial 7 Stem 3 or 4 to 6 or 10 inches long (varying with the depth of 

 water), filiform, dichotomously and diffusely branching, smooth. Leaves 2 to 6 

 lines long, and about 1 line wide, varying from ovate-oblong and ebtuse to lance - 

 linear and acute, very minutely serrulate (under a lent), nerveless, smooth, green 

 and shining, sessile, generally in verticils of three, and numerous on the stem,— 

 giving the plant the appearance of an aquatic moss. Flowers emerging ; perianth 

 •fa pale dingy-purple, or flesh-colored with a leaden tinge (white, Pursh, Torr. 

 Beck), the tube very slender, half an inch to near an inch long. 



Mab. Sluggish rivulets : frequent. Fl. July— August. Fr. 



Obs. This occurs in still water, along the margin of the Branrfywine and 

 Schuylkill, and in their tributaries,— where it was collected by Mr. Joshua 

 Hoopbs in 1828. I have not yet had an opportunity to examine the staminate 

 flowers, nor the mature fruit. It is the only known species in the U. States,— if 

 not of the genus. 



[Laurus. Enneandria Monogynia.] 



Order 10. Polyandria. 



456. MENI8PERMUM. L. Nutt. Gen. 804. 

 [Greek, Mene, the moon, and Spcrma, seed ; from the lunate form of the seeds.] 



Sepals and petals arranged in fours, in 2 or 3 series. Stamin ati 

 Fl. Stamens 16 to 20; anthers 4-lobed, at the apex of the thickened 

 or clavate filaments. Pistillate Fl. Ovaries 2 to 4, superior, 6ub. 

 pedicillate. Drupe baccate, roundish-reniform, with a single lunate 

 nut , or seed. 



SvffrtUicose : stem volubile ; leaves alternate, petiolate, peltate, or cordate, pal- 

 Mate-nerved, without stipules ; flowers in axillary or super-axillary peduaca* 

 latt racemes. Nut. Ord. 23, Lindl. Mknispbrmb*. 



