458 Rydberg : Notes on Philotria Raf. 



Michx. as a synonym but described the plant as dioecious, the 

 staminate flowers with nine stamens in two series, the inner of 

 which has three stamens, and the pistillate flowers with three sterile 

 filaments and three ligulate bifid stigmas. He added further : 

 "flowers very small and evanescent, the female emerging ; the male 

 migratory, breaking off connection usually with the parent plant, 

 it instantly expands to the light, the anthers also burst with elasticity 

 and the granular pollen vaguely floats upon the surface of the 

 water." He described the leaves as oblong-linear, minutely ser- 

 rulate, and partly obtuse. 



Torrey* described Udora as being polygamous. "Sterile 

 flTowers]. Stamens 9 : anthers oval, nearly sessile. Perfect 

 FL [ owERs] . Tube of the perianth produced above the ovary into a 

 very long slender tube. Stamens 3-6 : filaments short, subulate : 

 anthers oblong, innate ; the cells parallel, distinct . . . stigmas 3, 

 large, spreading, oblong-cuneiform, 2-lobed." He described the 

 leaves as varying from oblong-ovate to lanceolate-linear. 



How are these conflicting descriptions to be reconciled ? Have 

 some of the authors mentioned been mistaken ? Are there more 

 than one species confused or is Philotria canadensis (Michx.) Brit- 

 ton such a variable plant both as to flowers and leaves ? If more 

 than one species, are they all polygamo-dioecious with three kinds 

 of flowers : staminate with very short calyx-tube and 9 stamens ; 

 pistillate with long tube and no stamens or merely rudimentary 

 filaments ; and hermaphrodite flowers with long tube and 3-6 

 stamens ? These are questions to be answered and botanists who 

 have a chance to study the plants in the field will be well paid in 

 investigating these interesting water-weeds. The writer would 

 also be very thankful for material. 



Let us see what is the present knowledge of the genus. Let 

 us take up the different species proposed and the different descrip- 

 tions, in the order they appear. 



Elodea CANADENSIS Michx. Fl. Bor.-Am. i : 20. 1803. 



This was described as having hermaphrodite flowers with 3 

 stamens and bifid stigmas, and oblong, obtuse leaves. Is there 

 such a plant ? Caspary, who saw the original Michauxian material 

 at Paris, stated that the two flowers found there were hermaphrodite 



*F1. N. Y. 2 : 264. 1843. 



