Feb., 1904.] Nymphaeacae and Helobiae. 85 



Although there is much variation in the number of parts, typi- 

 cal specimens were selected to represent the diagrams accompa- 

 UN-ing this paper. Each diagram given represents an actual 

 flower of the species. The descriptions following represent what 

 to the writer appears to be the correct characterization, so far as 

 number and arrangement of parts are concerned, of the flowers of 

 the species studied : 



Caboviba caroliiiiana Gr. — Flowers hypogynous, pentacyclic, 

 actinomorphic, trimerous, with all the parts separate ; sepals 3, 

 petals 3, stamens 6, carpels 3 more or less (Fig. 7). 



Brasenia purpurea (Mx. ) Casp. — Flowers hypogynous with all 

 the parts separate ; perianth cyclic, trimerous ; androecium and 

 gynoecium spiral, stamens 18 more or less, carpels 9 more or less 

 (usually 6-18) (Fig. 8). 



NyiupJiaea advena Sol. — Flowers hypogjmous with the parts 

 separate except in the gynoecium ; calyx and corolla cyclic, tri- 

 merous ; androecium and staminodes spiral ; staminodes stamen- 

 like, 18 more or less; stamens 250 more or less, arranged in 

 spirals with about 14 circles of 18 stamens each ; gynoecium 

 cyclic of 18 carpels more or less, completely united in i cycle 

 forming a plurilocular ovulary (Fig. 10). 



Castalia odoiata (Dr)\) W. & W. — Flowers with partly epigy- 

 nous stamens, staminodes and perianth ; calyx cyclic of 3 sepals ; 

 corolla and staminodes not separable, spiral ; original petals 

 probably 3, the staminodes arranged in about 7 circles of 6 divi- 

 sions each, passing gradually into fertile stamens; stamens 100 

 more or less, spirallj- arranged in about 17 circles of 6 divisions 

 each ; carpels 18 more or less, united in i cycle forming a pluri- 

 locular ovulary (Fig. 11). 



Castalia tubcrosa (Paine) Greene. — Flowers with numerical 

 plan about the same as in C. odorata, but the arrangement much 

 displaced so that there are apparent!)- 4 sepals, and 4 petals of 

 the second cycle. There is also a disarrangement of the stamin- 

 odes (Fig. 12). 



Neluiiibo lutea (Willd.) Pers. — Flowers hypogynous with 2 

 dimerous cycles of sepals and 3 petals in the first corolla cycle ; 

 the remaining petals or highly modified staminodes spirally 

 arranged in about 7 circles of 3 each ; stamens 1 50 more or less, 

 spirally arranged, falling into 6 circles of 24 each ; carpels 18 

 more or less, distinct, situated in pit-like depressions of the large 

 top-shaped receptacle, arranged into several imperfect circles of 

 3s, 6s, 9s, etc., representing a primitive spiral arrangement 

 (Fig. 13). 



There has been no constancy in the progressive development of 

 the ovule in the Helobiae ; for in the epigynous Hj-drocharitales 

 we have both orthotropous and auatropous ovules, while in the 

 hypogynous Alismaceae as in Alisma and Sagittaria the ovule 



