The Morphology of Ruppia Maritima. 151 
and one can easily see a small prominence (fig. 106, cot), accompanied 
interiorly by a number of cell-divisions, which is obviously the be- 
ginning of the cotyledon. Moreover, at its right is another markedly 
meristematic region, the future stem apex or epicotyl (fig. 106, sé). 
Wille’s description of the subsequent development up to the 
mature embryo agrees essentially with my slides, so that I confirm 
his observations in the main, adding a few details. For the sake 
of clearness, each member will be described separately. 
The Cotyledon. Originating as described above, the cotyledon elon- 
gates and the epicotyl develops at its base. In the course ofits growth, 
the cotyledon develops basal sheaths similar to those characteristic of 
the leaves of a mature plant, which then surround the epicotyl. 
Concerning this condition Wille (1883, pp. 3, 4) says, “Hos den 
modne Frugt er Plumulaen ganske omgiven af Cotyledonet (Tavl. 
I, fig. 25), kun en trang Spalte ferer ind til Hulen,” but figures an 
embryo with a large open hollow at the base of the cotyledon, 
where the epicotyl may be seen. As a matter of fact, in Ruppia 
maritima at least, the cotyledonary sheaths overlap one another 
for almost the whole of their length, essentially as do the sheaths 
of the foliage leaves (Pl. XV, fig. 118). Only at the upper end of 
these sheaths is there a small cleft remaining (Fig. 118, x) which 
may be the “trang Spalte” mentioned by Wille. Thus the sheaths 
enclose the epicotyl so that it is quite shut off from view. In 
Pl. XIV, fig. 112, and Pl. XV, fig. 116 these sheaths appear in 
section in not quite mature embryos, and figures 117 and 118 show 
them in a cotyledon dissected from a mature embryo. It is inter- 
esting to note that the axillary scales may be seen within the sheaths, 
at their base, as in the mature plant. 
Wille (1883, Pl. I, fig. 25) figures the cotyledon as elevated a 
considerable distance above the hypocotyl, although still extend- 
ing more or less horizontally, and one might conclude that pos- 
sibly herein is a specific difference between Ruppia rostellata and 
Rk. maritima, were it not for the fact that Irmisch (1858, fig. 37, 
pl. I) figures the cotyledon closely appressed to the hypocotyl as 
I find it in FR. maritima (Pl. XV, tig. 119). In Text-fig. 28, p. 152, 
this horizontal position has been slightly disturbed through manip- 
ulation. 
The Epicotyl. Pl. XIV, fig. 112 shows the epicotyl in a nearly 
mature embryo. It consists always of a second leaf and the growing 
point, the latter not appearing as prominently here as in other sections. 
Wille (1883, p. 3, figs. 25 and 26) is in doubt whether this smaller pro- 
