406 MR. B. CLARKE ON THE EMBRYOS OF ENDOGENS 
the cotyledon. On the face of the germinated cotyledon in Commelyna tuberosa, and 
another species, there is always present à small process looking like a bud, which is not, 
however, present on any of the succeeding leaves; possibly it may be analogous to the 
buds that occur on the ribs of the inferior paleæ of the Grasses. 
Juncaceæ.—As this family is intermediate between Liliacee and Cyperacee and their 
allies, and its limits are not well defined, its germination presented a more than usually 
interesting subject of inquiry, and was rather expected to prove like that of the Liliacee. 
Luzula campestris is, however, distinctly endorhizal, being more so than the Cyperacee, 
and, I believe, strictly agrees with the Commelynacee in this character; it may therefore 
serve to show that Juncacee have no near affinity with either Ziliacee or Palmacee, 
from which they further differ in the cotyledon, as growth advances, becoming elevated 
on a cauliculus. The coleorhiza is of delicate texture, and disappears within a day or two 
from the enlargement of the root*. The cotyledon has a well-defined opening for the 
plumule, the first leaf of which is directly away from it. (Fig. 23.) 
Hydrocharidee.—This family has the embryo (the plumule only being rather larger) 
as well as the habit of Naiadee and their allies, and so may, perhaps, supply a connecting 
link between the hypogynous and epigynous Endorhizæ. It also agrees with them in 
having the first leaf of the plumule directly away from the cotyledon. 
Marantacee.—The germination of Canna indica has been figured by Richard with _ 
his usual accuracy +, with the exception of the primary radicle, which, from his figures, 
might be supposed to possess a coleorhiza of the same kind as the secondary, which is not 
at all the case. The coleorhiza of the primary radicle is of comparatively delicate texture, 
and unless the germination is daily examined from its commencement, may escape 
observation, as it very soon disappears entirely; whereas the secondary radicles break 
through the epidermis from a considerable depth, and the torn fissures through which 
they escape remain for a much longer time. At the last stage figured, the coleorhiza of 
the primary radicle has almost or entirely disappeared, so that the appearance of it there 
represented is, I believe, only that of the lateral radicle on either side reftected down 
upon it. The first leaf of the plumule alternates with the cotyledon, and as germination 
advances, the cotyledon sends up a stipulary process, forming a short sheath for the 
growing plumule. 
Alismacee and Butomacee.—In the germination of Actinocarpus Damasonium the 
plumule becomes elevated on a cauliculus, which elongates, while the radicle has scarcely 
rg the first two leaves of the plumule are lateral, i. e. neither directly 
dote. hes E = nor directly away from it, but yet, as growth advances, the external 
; à tendency to turn more directly away from it. Butomus umbellatus 
sr ss Ese way, the cotyledon having a very distinct fissure for the emussio® 
€: iem e, > its first leaf is directly away from the cotyledon. The germination 
y observed, and no trace of a coleorhiza was perceptible. (Figs. 24 & 25.) 
* $ vir 
The coleorhiza cannot be seen unless the seed is first completely deprived of its mucilaginous coat by placing d : 
e 
water fi i : : : 
DE or two or Mme days, when it swells, and is easily removed. If this is not done, the radicle becomes cov 
with mucus, so as entirely to prevent observation. | 
t Ann. du Muséum d'Hist, Nat. tom. xvü, pl. 5. figs. 3, 4, 5, 6. 
