Feb., 1904 .] 
Nymphdeacae and Helobiae. 
Ss 
Although there is much variation in the number of parts, t3’pi- 
cal specimens were selected to repre.sent the diagrams accompa- 
n3’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 : 
Cahomba caroliniana Gr. — Flowers li3’pog3mous, pentac3’clic, 
actinomorphic, trimerous, with all the parts separate ; sepals 3, 
petals 3, stamens 6, carpels 3 more or less ( Fig. 7). 
Brast’nia purpurea (Mx. ) Casp. — Flowers hypogynous with all 
the parts separate ; perianth C3"clic, trimerous ; androecium and 
gynoecium .spiral, stamens 18 more or less, carpels 9 more or less 
(usually 6-18) (Fig. 8). 
Nymphaea advena Sol. — Flowers hypog3-nous with the parts 
separate except in the gynoecium ; calyx and corolla C3’clic, 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; g3'noecium 
cyclic of 18 carpels more or less, complete^' united in i C3’cle 
forming a plurilocular ovular3' (Fig. 10). 
Castalia odotaia (Dr3^) W. & \V. — Flowers with partly epigy- 
nous stamens, staminodes and perianth ; caly-x C3'clic 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 gradual^’ into fertile stamens ; stamens 100 
more or less, spiral^’ arranged in about 17 circles of 6 divisions 
each ; carpels 18 more or less, united in i C3’cle forming a plnri- 
locular ovulary (Fig. ii). 
Casfa/ia tubcrosa ( Paine) Greene. — Flowers with numerical 
])lan 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 C3’cle. Tliere is also a disarrangement of the stamin- 
odes ( P'ig. 12). 
N^cliuuho lutca (Willd.) Pers. — P'lowers li3’pogynous with 2 
dimerous C3’cles of sepals and 3 petals in the first corolla C3’cle ; 
the remaining petals or highF" modified staminodes spiral^" 
arranged in about 7 circles of 3 each ; stamens 150 more or less, 
spiral^' 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, gs, etc., repi'esenting a primitive spiral arrangement 
(Fig. 13). 
There has been no constanc3* in the progressive development of 
the ovule in the Helobiae ; for in the epigynous H3'drocharitales 
we have both orthotropous and auatropous ovules, while in the 
hypogynous Alismaceae as in Alisma and Sagittaria the ovule 
