304 The Ohio Naturalist. [Vol. V, No. 5, 



NOTES ON THE MORPHOLOGY OF PHILOTRIA. 



LuMiXA C. Riddle. 



The studv of Philotria canadensis', was begun bv the writer in 

 July, 1902, with the expectation of making a careful investiga- 

 tion of its morphological characters. 



On account of difficulty in obtaining a complete series the 

 work was delayed and in the meantime a preliminary report on 

 the same subject was presented at the St. Louis meeting of the 

 American Association for the Advancement of Science by R. B. 

 Wylie and later the paper was printed in full, Bot. Gaz. 37: 1-22. 

 So carefully has he worked out nearly every detail that there 

 seems little to add to the subject except in the way of verifica- 

 tion. Yet it is thought advisable to make a note of some of the 

 most important points. 



Material for study was collected from Sandusky Bay, Lake 

 Erie where the plant grows more or less abundantly but blooms 

 rather uncertainly. None of the material obtained gave satis- 

 factory stages beyond fertilization. The staminate flowers were 

 found on the opposite side of the Bay from the carpellate colony. 



The staminate flowers were uniformly of nine extrorse bi- 

 sporangiate stamens, the three center ones being more or less 

 united by the filaments and in some cases these extended above 

 so as to form a resemblance to a stigma. Staminodia were found 

 also in the carpellate flowers, but these showed no traces of 

 sporangia. 



Measurements of flowers which gave the archesporial cell 

 stage were about 4 mm. long. Opened flowers varied in length 

 according to the distance of the stem at their origin from the sur- 

 face of the water. The average length was about 100 mm. or 

 4 inches. 



The single archesporial cell cuts oft' one parietal cell usually. 

 The primary sporogenous cell is always much the larger and 

 divides into four megaspores the lowest being the functional one. 

 The upper one was often quite long and was usually the last to 

 succumVj to the rapidly enlarging embryo sac. The widening of 

 the embr\'o sac was great in onlv one plane and was not very 

 marked when sections were cut at right angles to that plane. 

 The pouch-like form of the antipodal region was very noticeable. 

 Miss Burr found a similar pouch in \'allisneria, Ohio Nat. 4: 439- 

 443. In everv case three pale vcscicular nuclei could be found 

 deep in the pouch. In some cases a large brightly stained nucleus 

 was found just above the antipodals but careful examination 

 showed that it was either the lower polar nucleus in a typical 

 eight celled embryo sac or else the evidence was that there had 

 been a division of the definitive nucleus and one of the first 



