ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 551 



period of opening and closing of flowers. Among the more interesting 

 of these are the following : — The fact that some flowers remain open 

 for a longer period in summer than in spring is not due to the direct 

 effect of the increase in light, but to an increase in temperature result- 

 ing from the absorption of light. With many flowers the opening is 

 not the result of growth, but of changes in the turgor due to transpira- 

 tion. In some cases (Memerocallis flava, Hibiscus trionum), flowers 

 which in the summer remain open only for a single day, will, in the 

 autumn, open on two or three days in succession. 



Floral Organs of the DisciflorsB.* — L. Beille points out that the 

 andrcecium of the Disciflorae (in which class he includes the Euphor- 

 biacere) presents itself in three types, — the isosteraonous, the poly- 

 stemonous, and the diplostemonous ; the latter may be eudiplostemonous, 

 when the outer whorl of stamens are placed opposite the sepals, or ob- 

 diplostemonous, when they are placed in front of the petals. In the 

 Euphorbiaceas all three types of andrcecium occur. The highest type 

 of the obdiplostemonous Discifloraa occurs in the Butaceaa, Diosmeaa, 

 Zygophylleae, Aurantieaa, and Anacardiaceaa ; in the Bhamneaa, Am- 

 pelideae, Celastrineas, Staphyleaa, and Ilicineaa, it is simplified by the 

 suppression of one of the two whorls of stamens. Of the eudiplo- 

 stemonous Disciflorae the highest type is found in the Melieaa and 

 Goriarieaa ; in the Sapindeaa, Hippocastaneaa, and Acerineaa, it is again 

 simplified by suppression. 



Inflorescence of the Asclepiadeae. f — G. 0. A. Malme has studied 

 the nature of the extra-axillary inflorescence in a large number of 

 Asclepiadeaa natives of Brazil. From a comparison with those species 

 in which the inflorescence is truly axillary, the author comes to the 

 conclusion that in all cases it owes its true origin to an axillary bud, 

 from which position it has in certain cases become more or less dis- 

 placed. The extra-axillary position of the inflorescence is in all cases 

 associated with a very great size of leaf. 



Heterogyny of Ephedra campy lopoda4 — Dr. F. Cavara argues in 

 favour of the specific distinctness of this form from E. fragilis, on the 

 ground of the constant presence of rudimentary female flowers in the 

 male inflorescence. He thinks it probable that E. campylopoda is a 

 survival of a primitive type of the genus with androgynous flowers. 

 The paper concludes with a preliminary note on the process of amitotic 

 division of the nuclei in the endosperm. 



Pappus of Compositae. § — B. Frieb distinguishes, from a structural 

 point of view, three types of pappus in the Composite : — (1) In the 

 great majority of the genera — Hieracium, Solidago, Senecio, Grepis, Aster, 

 Eupatorium, Erigeron, Inula, &c. — the cells of the pappus rays put out 

 projections in the form of teeth or spines on their tranverse septa. This 

 form is adapted either for carriage by the wind or for adhering to the 

 fur of animals. (2) In Centaiuea, Serratida, and some other genera, all 



* Comptes Rendus, cxxxii. (1901) pp. 1497-9. 



t Ofv. k. Vetensk.-Akad. Forh., Stockholm, 1900, 23 pp. and 9 figa. See Bot. 

 Centralbl., lxxxvi. (1901) p. 417. 



t Bull. Sue. Bot. Ital., 1901, pp. 37-41. 



§ Oesterr. Bot. Zeitschr., li. (1901) pp. 92-6 (10 figs.). 



2 P 2 



