62 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
appear to be modified cells of the epiderm of tbe perianth, which have 
become enormously elongated. Their function appears to be undoubtedly 
connected with pollination. They serve either to collect the pollen- 
grains or to prevent the visiting insect from passing behind the stamens, 
and thus missing the stigma. A proposed classification is appended of 
the species of Thesium, according to the structure of the flower. 
Structure of the Integument of the Seed of Papilionaceae.* — 
Sigg. 0. Mattirolo and L. Buscalioni have examined the structure of 
the testa of the seed in a number of species of Papilionaceae, that of 
Phaseolus being described in detail. 
The testa consists of three layers — the layer of Malpighian cells 
(wax, clothing layer, or “ linea lucida the layer of columnar cells, 
and a lower layer. The outermost layer does not correspond to the 
cuticle, but to the clothing-layer of the intercellular spaces. Between 
the deeper layer of the testa and the endosperm is a separating layer, 
the cells of which are united by strings of protoplasm ; sieve-tubes were 
found in the vascular bundle of the funicle. In the chilary layer of the 
seed is a small pit, bounded by two motile lip-shaped structures, which 
the authors call the chilarinm. The hygroscopic separation of these 
structures causes the rupture of the testa. The purpose of the “ linea 
lucida ” appears to be the regulation of the absorption of water. The 
so-called “ twin tubercles ” of the seed appear to exercise a pressure on 
the vascular bundle which runs beneath them, especially on its phloem- 
portion, and thus prevent an excessive flow of nutrient material for the 
seed. The micropyle facilitates the entrance of fluids and gases into 
the interior of the seed. 
Seedlings.t — Sir John Lubbock gives in these volumes an account 
of a long series of experiments on the growth and development of seed- 
lings, principally of Dicotyledones, especially in relation to the con- 
nection between the form and structure of the cotyledons and that of 
the permanent leaves. After a general introduction, the phenomena 
connected with the germination of a very large number of species, 
arranged in their natural orders, are described. The various forces 
which influence the growing plant are discussed, and the author arrives 
at the general conclusion that, in the great majority of cases, it is the 
form of the fruit that governs that of the seed, and the form of the seed 
that determines that of the cotyledons. 
Branching Palms4 — Mr. D. Morris enumerates the tribes and 
genera of palms in which branched or forked stems occur. Branching 
is habitual in some species, and occasional in other species, of Hyphsene , 
and is also occasional in certain species of Bhopalostylis, Areca, Dictyo- 
sperma, Oreodoxa, Leopoldinia, Phoenix , Nannorhops, Borassus , and Cocos. 
The branching is frequently the result of injury to, or destruction of, 
the terminal bud, causing the development of adventitious or axillary 
buds below the apex, which produce branches. In some species it is 
* Mem. It. Accad. Sci. Torino, xlii. (1892) 186 pp. and 5 pis. See Bot. Ztg., 1. 
(1892) p. 694. Cf. this Journal, 1890, p. 625. 
t ‘ A Contribution to our Knowledge of Seedlings,’ London, 8vo, 1892, 2 vols., 
608 and 646 pp. and 684 figs. 
X Journ. Linn. Soc. (Bot.), xxix. (1892) pp. 281 -98 (7 figs.). 
