508 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the “ djati-tree ” of Java. After the first formation of the embryo and 
suspensor, the embryo-sac undergoes constriction * * * § into a long slender 
upper portion and a short ovoid lower portion, the latter containing the 
embryo and suspensor, the apex of which sometimes penetrates the upper 
portion. The endosperm is differentiated into an upper and a lower 
portion. The former is composed of a small number of moderately large 
very irregular cells, with very thin walls, containing large oil-drops and 
inconspicuous nuclei. The lower endosperm is composed of much 
smaller tolerably regular globular or polyhedral cells with thicker walls, 
and a hyaline protoplasm containing very small oil-drops and large con- 
spicuous nuclei. Both portions of the endosperm are subsequently 
almost entirely resorbed, only a very thin layer remaining in the mature 
seed. Along with the suspensor there are developed a number (10-20) 
of vesicular endosperm-cells, which apparently serve to convey the nutrient 
material from the rest of the endosperm to the suspensor, from which it 
reaches the embryo. They disappear along with the suspensor. 
Starch was but seldom found in the embryo, and the author is of 
opinion that the outer cells of the upper endosperm have the faculty of 
transforming both starch and sugar into oil. This transformation takes 
place chiefly at the boundary of the upper and lower endosperm, whence 
it is conveyed, through the lower endosperm, to the vesicles, the suspen- 
sor, and finally to the embryo. 
Ovule and Embryo-sac of Vincetoxicum.f — M. Gr. Chauveaud de- 
scribes the peculiarities in the structure of the ovule of Vincetoxicum 
officinale. He reverts to the earlier view, in opposition to that of 
Warming, that the nucellus is entirely naked, without integument. A 
single hypodermal cell of the original papilla which constitutes the ovule 
developes directly into the embryo* sac without undergoing any division, 
a process which has not been observed before in dicotyledons. Strictly 
speaking the whole of the tissue beneath the epiderm, that is, the whole 
of the nucellus, is reduced to an embryo-sac. As this cell grows it 
inserts itself between the four epidermal cells which surround it ; these 
separate from one another ; and the space thus formed is the origin of 
the micropylar canal. 
Cleistogamous -Flowers of Polygonum.J — Prof. S. Coulter finds 
cleistogamous flowers on a large number of species of Polygonum , 
including the British species P. Hydropiper , lapathifolium , maritimum , 
and Persicaria. In P. Hydropiper they are particularly abundant. 
The cleistogamous flowers are especially produced late in the season, 
are completely concealed by the sheath, and appear invariably to ripen 
their achenes. 
Mr. T. Meehan § finds cleistogamous flowers to be exceedingly 
common in P. acre ; they are apparently invariably fertile and are of a 
special kind found in no other species, small white flowers hidden 
beneath the ochrea of the leaf. 
* Cf. this Journal, ante, p. 232. 
t Comptes Rendus, cxiv. (1892) pp. 313-5. 
X Bot. Gazette, xvii. (1892) pp. 91-2. Cf. this Journal, ante, p. 232. 
§ Proc. Acad. Nat. Sci. Philadelphia, 1892, pp. 163-4. 
