.412 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Decropliorous Coleoptera, the species which are by far the most active 

 agents being Saprinus nitidulus and seneus. 



Cleistogamic Flowers.* — Herr A. Schulz confirms Magnus's state- 

 ment I of the occurrence of cleistogamic flowers in Speryularia salina, 

 and has observed the same phenomenon also in Sagina Linnsei, SclerantJius 

 annuus, and Stellaria Borreana. The suppression of the corolla is in 

 these cases also accompanied by a reduction in the number of stamens. 

 The production of these autogamous or self-pollinated flowers appears to 

 be dependent on unfavourable climatal conditions. 



Parasitic Castration of Lychnis dioica.ii: — M. A. Giard confirms the 

 observations of Magnin § with regard to the effects produced on the floral 

 organs of Lychnis dioica by the attacks of Ustilago antherarum, and 

 extends them also to Silene inflata. He regards it as an example in the 

 vegetable kingdom of a phenomenon which he had previously || described 

 in Crustacea and other animals as parasitic castration, caused by the 

 attacks of parasites, and resulting in partial or complete sterility, from 

 the substitution of one kind of sexual organ for the other. This para- 

 sitic castration may be androgenous when it produces in the female sex 

 characters which belong ordinarily to the male sex, thelygenous when the 

 reverse is the case, or amphigenous when it mingles the characters of 

 both sexes by developing in each some of the characters of the other sex. 



Fly-catching Habit of "Wrightia coccinea.^ — Mr. A. Tomes describes 

 the peculiar structure in this plant by means of which insects (ants and 

 flies), when seeking the honey in the nectaries, are caught in slits between 

 the anthers, and then perish. The contrivance appears to be essentially 

 connected with cross-fertilization ; self-fertilization being apparently 

 rendered impossible by the structure and relative position of the anthers 

 and stigmas. There is no evidence of the plant being insectivorous. 



C2) Nutrition and Growth (including- Movements of Fluids). 



Absorption of Light in assimilating leaves.** — Dr. E. Detlefsen 

 has attempted the determination of the question whether the absorption 

 of light in a green leaf which is not assimilating, is the same in amount 

 as that of the same leaf while assimilating. He describes an apparatus 

 in which an object can be exposed alternately to streams of air containing 

 carbon dioxide and free from it, and the experiments from which he con- 

 cludes that the quantity of light absorbed by an assimilating leaf is 

 always greater than that of the same leaf in sunshine in an atmosphere 

 containing no carbon dioxide ; though the discrepancy is not great. 

 About 0*8 per cent, of the kinetic energy of the sunlight which falls on 

 an assimilating leaf is converted into potential energy. 



Absorption of Nitrogen by Plants.jt — Herr B. Frank has under- 

 taken a series of experiments for the purpose of determining whether the 

 source of nitrogen in the soil for the food of plants is supplemented by 



* SB. Ges. Naturf. Freunde, 1888, pp. 51-3. 



t Cf. this Journal, 1888, p. 994. 



X Comptes Rendus, cvii. (1888J pp. 757-9. 



§ See ante, p. 85. ll This Journal, 1888, p. 414. 



1 Scient. Mem. by med. officers of the army of India., part iii. (1888) pp. 41-3. 

 ** Arbeit. Bot. Inst. Wiiizbm-g, iii. (1888) pp. 534-52 (3 figs.), 

 tl- Laudwirth. Jahrb., 1888, pp. 419-554. See Bot. Ceutralbl., xxxvii. (1889) 

 P, 248. 



