440 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 

 a. Anatomy.* 

 CI) Cell-structure and Protoplasm. 

 Nuclear Origin of Hyaloplasm-t— M. C. Degagny states that ob- 

 servers who arc interested in the phonomena which accompany the 

 indirect division of the nucleus, or karyokincsis, have asked if there is 

 not in the nucleus, besides chromatic bodies, nucleoli, and nuclear sap, 

 other plasmic matter which in certain cases is seen in the form of granu- 

 lations, for example, in the nucleus of the mother-cell of the embryo-sac 

 of the lily. If sections of the endosperm of the fritillary, lily, or iris bo 

 examined when the embryo-sac is not completely full, one finds all tho 

 nuclei of a certain region inclosing a hyaline matter which might be 

 taken for an agglomeration of protoplasm; but this matter, which is 

 very abundant in certain nuclei, is less so in others. 



The author concludes by stating that the formation of carbohydrates 

 and the formation of protoplasm are brought about by the dissemination 

 or disorganization of nuclear substances In the formation of protoplasm 

 there are two distinct phases separated by a total change in molecular 

 condition. In the first phase of its existence the fundamental protoplasm 

 retains the crystalline form, like homogeneous inorganic substances in 

 which the cohesion i& uniform. In the second phase it is reorganized, 

 and passes into the colloidal or amorphous state. 



Three Nuclei in Pollen-grains. £ — Mr. B. D. Halsted describes the 

 structure of some pollen obtained from Sambucns raeemosa. When 

 viewed dry, the pollen-grains are about twice as long as broad, and 

 exhibit three dark longitudinal lines or sutures. For germination, fresh 

 pollen was placed in a 10 per cent, solution of cane-sugar ; and by means 

 of the colouring substances eosin and azo-rubin, tho author was able to 

 determine the presence of three nuclei in nearly all the tubes. When 

 only two nuclei were found in a grain or its tube, one was frequently 

 larger than tho other. This fact led to the suggestion that the larger 

 or vegetative nucleus may undergo a process of division early in the 

 development of the pollen-grain. 



Nuclear and Cell-division. — Herr E. Zacharias § contests the view 

 of Strasburger and Berthold, || that, during the division of the nucleus, 

 while it is passing over into the spindle-condition, the cell-protoplasm 

 enters it, so that a sharply defined nucleus no longer exists, but the 

 sections of its framework lie free in the cytoplasm. The observations 

 were made on pollen-mother-cells of Hemerocallis and Tradescantia, 

 epidermal cells of Tradescaniia, and rhizoids of Chara, the latter in a 

 living condition. 



Zacharias finds that the nucleus does not give up its individuality 



* This subdivision contains (1) Cell-structure and Protoplasm ; (2) Other Cell- 

 contents (including Secretions); (3) Structure of Tissues; and (4) Structure of 

 Organs. f Bull. Soc. Bot. France, xxxiv. (1887) pp. 365-72. 



I Bot. Gazette, xii. (1887) pp. 285-8 (1 pi.). 



§ Bot. Ztg., xlvi. (18S8) pp. 33-40, 51-62 (1 pi.). 

 See this Journal, 1887, p. 420. 



