Feb., 1904 .] 
Nymphaeacae and Helobiae. 
87 
19). There is the same opening on one side, and on the back a 
connection of the two lobes, only to a less extent. Unless special 
care were taken in reconstructing such an embrj'o from serial sec- 
tions, one might readily take it for a Dicotyl. It will be evident, 
however, from a comparison of the figures that the Castalia 
embryo represents only the extreme of the lobing shown in 
Nelumbo and Nymphaea. 
There is a structure present in various Helobiae which deserves 
special attention in discus.sions on the relationship of the Nym- 
phaeaceae. The so-called macropodous embryos of Halophila, 
Ruppia, Zostei'a and other genera appear to the writer to throw 
considerable light on the peculiar structure of the Nymphaea 
embr3’o. The enormous development of the basal or hypocotyle- 
donary region of the embrj’o in such widely separated genera 
shows a strong and peculiar tendency in the group of Helobiae. 
In such typical forms as Sagittaria latifolia, Zannichellia palustris 
Fig. I. Similar part.s are indicated as follows : c, cotyledon, and h, the 
basal or lateral region developed into an expanded organ in some embryos. 
a — Knibryo of Sagittaria latifolia. b — Kmbryo of Zannichellia palustris. c— Embryo 
of Vallisneria spiralis, d - longitudinal half of embryo of Halophilia ovalis. after Balfour, 
e -Section of young embryo of Krythronium americannm showing beginning of ma.ssive 
development of basal region, f— Embryo of Ruppia rostellata, after Wille. g— Longitudi- 
nal half of embryo of Zostera maritiina, after Rosenberg, h —Young embryo of Nelumbo 
lutea, after I„5’on. i — Older embryo of Nelumbo lutea. aher Lyon. 
and \’allisueria spiralis (Text Fig. i, a, b, c) there is bareh' a 
hint of such a development. In some other Monocotyls, as, for 
instance, in Erythronium americannm, the ba.sal region of the 
embryo earl>’ shows a rapid development, growing into a massive, 
lobed structure which functions as an absorbing organ (Text Fig. 
I, e). This is no doubt the purpose of the massive expansions 
and lobes present in Halophila, Ruppia, Zostera, Nelumbo, Nym- 
phaea and Castalia (Text Fig. i, d, f, g, h, i, and Figs. 14-19). 
To the writer there is no more reason for calling the ridge or 
lobes of the N^miphaeaceae, cot3’ledons, than the remarkable 
expansion at the base of the embr3'o of Zostera. The basal 
expansion in the Castalia embryo, to the writer, cannot represent 
the same or homologous structure as the cotyledons of Sagittaria 
or Bursa. According to this view the so-called cot3’ledons of 
Nelumbo, N3'inphaea and Castalia represent li3’pocotyledonar3’ 
