342 HYDROCHARIDAOE^. 



CLASS II. ENDOGENOUS OR MONOCOTYLEDO- 

 NOUS PLANTS. 



Stem, with no perceptible distinction of bark, wood and pith, 

 increasing in diameter by the addition of new matter to the 

 centre. Leaves mostly alternate, with no evident articulation, 

 commonly sheathing at base and entire, mostly with parallel 

 veins. Embryo with but one cotyledon; or if two, one is 

 smaller and alternate with the other. 



SUBCLASS I. PETALOIDEALS. 



Stamens and pistils naked or covered by verticillate floral 

 envelopes. 



ORDER CXXIV. HYDROCHARIDACE^E. FROG'S BITS. 



Flowers in a spathe, mostly dicecious. Perianth regular, 

 3 6-parted ; the inner segments petaloid. Stamens 3 12. 

 Ovary 1 9-celled ; stigmas 3 6. Fruit dry or succulent, in- 

 dehiscent. Seeds numerous, without albumen. Floating or 

 water plants. Leaves mostly radical, sometimes opposite or 

 verticillate. 



1. UDORA. Nutt. Udora. 

 (From the Greek vto p, water ; in allusion to its place of growth.) 



Polygamous. Spathe bifid, 1 -flowered. Perianth 6-parted, 

 petaloid. STERILE FL. Stamens 9, 3 of them interior. PER- 

 FECT FL. Tube of the perianth very long and slender. Sta- 

 mens 3 6 ; filaments short, subulate. Style long and filiform. 

 Stigmas 3, large and spreading, 2-lobed. Fruit coriaceous, 

 few seeded: Seeds elliptic, smooth. 



IT. Canadtnsis Nutt. : leaves verticillate in threes and fours, lanceolate, 

 oblong or linear, finely serrulate ; tube of the perianth filiform. El-odea 

 Canadensis Mich. Serpicula verticitlata Muhl. 



Still waters. Can. to Virg. W. to Miss. Aug. 7J.? Stem submersed, dif- 

 fusely diehotomou.s. Flowers axillary, very small, whitish. The plant without 

 flowers resembles an aquatic moss. Little Water Snakeweed. 



2. VALLISNERIA. Linn. Tapeweed. 

 (In honor of Antonio Vallisneri^ an Italian botanist.) 



Dioecious. STERILE FL. Spathe ovate, 2 4-parted. Spa- 

 dix covered with minute flowers. Perianth 3-parted. Stamens 



