66 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Integument of the Ovule and Seed of Geum. * — L. Pechoutre has 

 investigated this process in the case of Geum urbanum, and states that, 

 as in the case of other so-called " exalbuminous " genera of Kosacere, the 

 term is not literally correct ; but the endosperm is reduced to a single 

 proteid layer of cells. The ovule is strictly monochlamydeous, the single 

 integument corresponding to the outer integument in bitegmentary seeds. 

 In the allied genus Dryas, the ovule is bitegmentary. 



Bulbiform Seeds of Amaryllideae.t — Dr. A. B. Eendle gives a de- 

 tailed account of what bad been previously known respecting these 

 singular structures, found chiefly in species of Amaryllis and Crinum, 

 and thus sums up the results. Tbree forms of seed may be dis- 

 tinguished : — A. True Seeds; (1) Developed from a normal ovule, the 

 outer integument of which becomes thick and fleshy after fertilisa- 

 tion, and forms the substance of the bulbiform mass (Hymenocallis) ; 

 (2) Developed from a naked ovule, the flesby substance being derived 

 entirely from the endosperm, which develops chlorophyll in its outer 

 layers, and continues to grow for some time (Crinum asiaticum, &c). 

 B. A vegetative growth rejjlacing the seed ; (3) A normal ovule is pro- 

 duced, but a viviparous growth of an adventitious shoot and root takes 

 place at its base, and a bulbil is formed, the ovule integuments forming 

 the outer coats (Calostemma Cunninghami). Germination of these struc- 

 tures follows a course common to many bulbs of Monocotyledons. 



Bending of Mature Wood in Trees. $ — The late T. Meehan calls 

 attention to the stupendous power exhibited by plant life in the enormous 

 weight lifted by roots, or shifted by the bending of boughs. This bending 

 may take place without a break in an old branch or trunk that would 

 require an immense mechanical pressure for man to accomplish. The 

 life-growth of a plant is, according to the author, in a measure a struggle 

 against gravitation ; it is to energy transmuted from nutrition that we 

 have to look for the various forms that plants assume. 



Causes of the Direction of Branches.§ — J. Baranetzky goes in great 

 detail into this subject from an experimental point of view, giving 

 the results of a large number of experiments on trees and shrubs. 

 It is discussed under the following heads : — The property of counter- 

 acting curvature (Gegenkrummung~) ; Experiments and observations 

 in the open air ; Unequal length in growth of the secondary woody 

 elements. Every unilateral growth of the stem incites, in many plants, 

 and especially in those that are woody, a more active growth on the 

 opposite side, in consequence of which the curvature may ultimately 

 become effaced. 



Floating Organs of Plants. || — H. Dingier gives a resume of our 

 knowledge of the parts of plants which assist in their distribution by 

 their power of floating in the air ; the subject being treated mainly from a 

 mathematical point of view, i.e. in regard to the mechanics of the motion. 



* Journ. de Bot. (Morot), xv. (1901) pp. 213-7. 

 t Journ. R. Hort. Boo,, xxvi. (1901) pp. S9-96 (5 figs.). 

 % Proc. Acad. Nat. Sci. Philadelphia, 1901, pp. 354-65 (2 pis.). 

 § Flora, lxxxix. (1901) Erganzbd., pp. 138-239 (20 figs.). 



|| Die Bewegung d. pflanzlichen Flugorgane, Miinchen, 1899, ix. and 342 pp. 

 and 8 pis. Sec Bot. Contralbl.', lxxxv'ii. (1901) p. 283. 



