618 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
ledons does not help one to predict the character of the foliage-leaves. 
Broad generalisations in regard to the shape of the cotyledons in plant- 
families cannot he safely made without a considerable mass of data. 
The hypocotyledonary and the epicotyledonary regions are, in their 
primary structure, essentially dissimilar. The epiderm of the hypocotyl 
is more often without trichome structures ; the cortex is thicker, and is 
composed of larger cells ; the endoderm is more distinct ; the pith is 
smaller; the sclerenchyme is often less well-developed and differently 
arranged ; there is very rarely a hypoderm. The distribution of starch 
is, as a rule, the same in both regions. As to the structure of the stele, 
there are in the hypocotyl usually four primary vascular bundles, occa- 
sionally a larger number. In the epicotyl the vascular bundles are from 
six to eight, or much more numerous. 
Seedlings of Jatropha multifida and Persea gratissima.* — Accord- 
ing to Mr. T. Holm the* seedling of Jatropha multifida (Euphorbiaceae) 
agrees with that of Myristica Bicuhyha, as described by F. Muller, in the 
remarkable peculiarity that the long hypocotyl raises the seed above the 
ground, and the cotyledons are provided with petioles of considerable 
length, and yet the cotyledons are entirely enclosed within the seed-coat, 
and fall off without being exposed to sunlight. In Persea gratissima 
(Lauraceae) the first four leaves of the seedling are in opposite pairs, 
and have distinct petiole and laminaa, while the succeeding five or six 
leaves are almost scale-like, with no petiole or lamina, but are covered 
with silky hairs like the axis and the succeeding leaves when young. 
Root-suckers of the Douglas Fir.f — Mr. F. H. Lamb notes the 
occurrence of root-suckers on the Douglas Fir, Pseudotsuga taxifolia. in 
the dense woods of western Washington. They are found only in the 
densest and moistest forests, and the plants arising from them are with 
difficulty distinguished from ordinary seedlings. 
Podophyllum peltatum.j; — Mr. T. Holm describes in detail the 
structure of this N. American plant, which presents the following pecu- 
liarities. In germination the blades of the two cotyledons are borne 
upon long petioles, which are united together in their whole length so 
as to form a cylindrical tube. The plumule is very minute, and is seated 
at the bottom of the cotyledonary tube. During the first year of growth 
the cotyledons are the only assimilating organs. The internal structure, 
like that of some other Ranunculaceae, resembles in some respects that 
of Monocotyledons, rather than that of ordinary Dicotyledons. The 
mestome bundles in the aerial stem are not arranged in concentric bands, 
but form three irregular bands, of which two are located in the pith. 
The leptome consists exclusively of sieve-tubes and their companion 
cells, the sieve-parenchyme being entirely wanting. 
Anatomical Structure of the Leafless VanillaeJ — M. E. Heckel has 
examined the structure of two leafless species of Vanilla — V. Phalsenopsis 
and aphylla — and finds the anatomical characters to differ widely from 
those of the leafy species, presenting features not hitherto found in the 
* Bot. Gazette, xxviii. (1899) pp. 60-4 (6 figs.). f Tom. cit., pp. 69-70. 
t Op. cit., xxvii. (1899) pp. 419-33 (10 figs.). 
§ Comptes Rendus, cxxix. (1899) pp. 347-9. 
