496 BURMANXIACE.E. (bUKMANNJA FAMILY.) 



the sterile flowers, 3 or 6 almost sessile anthers in the perfect flowers. (Elodea 

 Canadensis, Miclix., and E. latifolia, Caspary, who has recently well illustrated 

 this and the two related genera ; all perhaps to be reduced to one, Hydrilla. 

 Udora Canadensis, Nutt. Anacharis Alsinastrum (Babington), Nuttallii, and 

 Canadensis, also Apalanthe Schweimtzii, Planchon.) — Slow streams and ponds : 

 common. July. — Nat. in England, where it is very troublesome by its rapid 

 increase, filling navigable waters ; but no inconvenience of the sort is complained 

 of here in its native country. 



3. VALLISNERIA, Micheli. Tape-grass. Eel-grass. 



Elowers strictly dioecious : the sterile numerous and crowded in a head on a 

 conical receptacle, enclosed in an ovate at length 3-valved spathe which is borne 

 on a very short scape : stameus mostly 3. Fertile flowers solitary and sessile in 

 a tubular spathe which is borne on an exceedingly long scape. Perianth (calyx) 

 3-parted in the sterile flowers ; in the fertile with a linear tube coherent with the 

 1 -celled ovary, but not extended beyond it, 3-lobed (the lobes obovate) ; also 3 

 linear small petals. Stigmas 3, large, nearly sessile, 2-lobed. Ovules very nu- 

 merous, scattered over the walls, orthotropous. Fruit elongated, cylindrical, 

 berry-like. — Stemless plants, with long and linear grass-like leaves, growing 

 entirely under water. The staimnate clusters being confined to the bottom of 

 the water by the shortness of the scape, the flower-buds themselves spontaneously 

 break away from their short pedicels and float on the surface, where they 

 expand and shed their pollen around the fertile flowers, which are raised 

 to the surface at this time: afterwards the thread-form fertile scapes (2-4 feet 

 long, according to the depth of the water) coil up spirally, drawing the fruit 

 under water to ripen. (Named for Ant. Vullisneri, an early Italian botanist.) 



1 . V. spiralis, L. Leaves linear, thin, long and ribbon-like ( 1 ° - 2° long), 

 obscurely serrulate, obtuse, somewhat nerved and netted-veined. — Common in 

 slow waters. Aug. (Eu.) 



Order 113. BURHIAWWlACE^:. (Burmaxxia Family.) 



Small annual herbs, often with minute and scale-like leaves, or those of the 

 root grass-like; the flowers perfect, ivith a 6-cleft corolla-like perianth, the 

 tube of which adheres to the 1-celled or S-celled ovary : stamens 3 and dis- 

 tinct, opposite the inner divisions of the perianth ; pod many-seeded, the seeds 

 very minute. — A small, chiefly tropical family, of which only one species is 

 found within our borders. 



1. BURMANNIA, L. (Tripterella, Michx.) 



Ovary 3-celled, with the thick placentae in the axis. Filaments 3, very short. 

 Style slender : stigma capitate-3-lobed. Pod often 3-winged. (Named for 

 /. Burmann, an early Dutch botanist.) 



1. B. bifldra, L. Stem low and slender (2'-4' high), 2-flowered at the 

 summit, or soon several-flowered ; perianth (2" -3" long) bright blue, 3-winged. 

 (Tripterella caerulea, Michx.) —Peaty bogs, Virginia and southward. 



