202 Johnson. — On the Nursing of the Embryo 
with a dermatogen, which here and there is divided by peri- 
clinal walls. Beneath this dermatogen, at the radicular end 
and extending more than a third of the length of the embryo, 
the viscid tissue occurs. Its cells are very long, narrow, 
obliquely inclined towards the axis of the embryo, and multi- 
nucleate. Running through the viscid tissue, in a position 
coincident with the axial plane of the embryo, there is a 
plate of broader and vacuolated cells dividing the viscid tissue 
imperfectly into two masses. A layer of empty cells extends 
across the embryo cutting this viscid matter off from the rest 
of the embryo which may be termed the germinable part. 
This highly differentiated mature embryo is in marked con- 
trast with the young embryo (Fig. 21), which is undiffer- 
entiated. It may be that the viscid tissue represents the 
suspensor and that the closely aggregated cells in which the 
procambial strand ends constitute the true radicle which is 
then endogenous. Special pains were taken to make sure 
that the elongation of the embryo-sac backwards in its septate 
condition was not a suspensor, and strong confirmatory proof 
of the views previously given was furnished by one fruit in 
which the endosperm cells had grown round the curve of the 
placental embryo-sac tube and into its long arm (Fig. 22), 
at the same time that the embryo was distinct, independent, 
and in its usual position. 
Germination of the Embryo, etc. 
Sir Joseph Hooker has, in the Flora Antarctica, entered 
fully into the mode of germination of the seedling of M . 
br achy s t achy uni) DC., as well as into the connection of the 
adult parasite with the host branch. As in Viscum , the seed- 
ling’s root is independent of geotropism and its stem (hypo- 
cotyledonary) is negatively heliotropic. For interesting figures, 
showing the splitting into two of the viscid tissue by the 
growing radicle, and the mode of penetration of this to the 
host wood, the reader is referred to the Flora Antarctica. 
I was not able to observe normal germination in M. punctu - 
