70 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



variegatus, niger, roseus, &c,, and Lathyrus heterophyllus, the suspensor 

 is composed of only four cells, of which the two upper ones are very- 

 long and the two lower ones shorter and round or ovoid, supporting 

 the young embryo. They are derived, after fertilization, from a single 

 primitive cell, which divides both transversely and longitudinally, 

 subsequent to the division of its nucleus. In the protoplasm which 

 fills each of these cells, a larger number of nuclei are then formed by 

 the further division of the first four. The disposition of these nuclei 

 is not always regular ; they are usually scattered throughout the 

 layer of protoplasm which lines the cell-wall. They are most com- 

 monly spherical, but frequently ovoid, and are readily distinguished 

 from the nuclei of the embryo-sac. 



Although not necessary, the employment of reagents greatly 

 facilitates their observation. A solution of cochineal, very slightly 

 acidulated with acetic acid, gives them a red tinge which distinguishes 

 them from the pale rosy tint of the protoplasm. They have generally 

 a moderately large nucleolus. The same cell often presents them 

 in various stages of development ; they then resemble the nuclei of 

 the embryo-sac, but they never, like these, become clothed with a 

 cellulose-wall. 



The author is unable to assign a cause for this multiplicity of 

 nuclei. It is not exclusively the size of the cells ; as in some Orchideae 

 we find cells as large, with only a single nucleus. It is probably 

 connected with some physiological function. 



Open Communication between Endosperm-cells.* — An examina- 

 tion of the endosperm of certain seeds — Areca oleracea, Phtenix dac- 

 tylifera, Strychnos nnx-vomica and others — by Dr. E. Tangl, has 

 determined the fact that the thickened walls of the endosperm-cells 

 are penetrated by a system of canals, through which an open com- 

 munication is established between adjacent cells, causing a continuous 

 connection of their protoplasmic contents. This he believes to be of 

 great advantage to the plant in the germination of the embryo. An 

 analogy is drawn between the structure of this endosperm-tissue and 

 that of sieve-tubes. The endosperm of Strychnos is bounded outwardly 

 by a layer of elongated cells, the longer axis of which stands at right 

 angles to the surface of the tissue. Above this layer begins the true 

 endosperm-tissue, the cells of which, the nearer they are situated to 

 the centre, are larger and characterized by a greater capacity of 

 swelling in the cell-wall. It is these cell-walls through which the 

 communication-system appears to exist. 



Modification of Palisade-tissue. f — The ordinary palisade-tissue, 

 so commonly met with beneath the epidermis of the upper side of 

 leaves, consists of elongated tubular cells, with their longer axis at 

 right angles to the surface of the leaf, each cell constituting a 

 palisade. Haberlandt has observed in certain leaves a deviation from 

 this structure, in which the palisades are not single cells but branches 

 of cells. The walls of each cell are folded in at right angles to the 



* Jahrb. wiss. Bot., xii. (1880) pp. 170-90 (3 pis), 

 t Oesterr. Bot. Zeit., xxx. (1880) pp. ci05-6. 



