ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1 i 1 



In the palisade-tissue are a number of suberised " water-cells," distin- 

 guished from the neighbouring cells by their very large size. In moist 

 air the diameter of the cells of the leaf — i.e. of the organ which assimi- 

 lates and transpires most strongly — is lengthened in such a way as to 

 increase the surface which is in direct communication with the air. In 

 the cells of the stem this extension takes place chiefly in the axial 

 direction. The effect on the number of stomates of transplanting into a 

 moist air varies with the species. In some cases it is increased, in others 

 decreased. The results on the vegetative organs of a removal into a 

 moist situation are described in detail. 



C4) Structure of Organs. 



Heteromorphic Flowers of Helianthemum. * — J. H. Barnhart de- 

 scribes the heteromorphism which distinguishes most of the American 

 species of Helianthemum. In addition to the conspicuous flowers, 

 apetalous cleistogamic flowers are produced, in some years in the autumn, 

 in others along with the conspicuous flowers in the spring or summer. 

 The apetalous flowers have, as a rule, a larger calyx and shorter peduncle 

 than the conspicuous flowers. In the incomplete flowers the stamens are 

 always less numerous than in the complete ones, and the filaments are 

 much shorter, so that the anthers are in contact with the stigma, ensuring 

 self-fertilisation, and the ovules are always fewer. Intermediate con- 

 ditions between the two kinds of flower occur. 



Bud-blossoming of Deutzia gracilis.! — F. Ludwig records the ob- 

 servation that, under favourable conditions of weather, the flower-buds 

 of this plant will more or less completely open in almost any stage of 

 development. The phenomenon has no relation to cleistogamy ; these 

 early flowers have no functional reproductive organs, and soon wither. 



Peculiarity of Alpine Composite. :{: — Dr. A. von Hayek calls atten- 

 tion to the fact that in a large number of alpine Composite the involucre 

 has a strikingly dark tint. This occurs eitber in species peculiar to high 

 altitudes or in alpine varieties or races of species which do not present 

 this peculiarity at low elevations. Seeing the phenomenon is seen chiefly 

 in late-blossoming species, the author regards it as serving for the pro- 

 tection of the young fruits, which are enclosed in the involucre, and are 

 "thus protected against excessive changes in temperature between day 

 and night, the heat-rays being absorbed by their black covering. 



Inversion of the Ovule in Statice.§ — Ph. van Tieghem calls attention 

 to a not infrequent anomaly in the structure of some species of Statice, 

 especially S. puherula. Normally the ovule is attached to a long funicle, 

 at the extremity of which it is pendent. In the abnormal examples the 

 funicle remains short, and the ovule is erect. This is accompanied by 

 sterility, since the pollen-tube, when it reaches the chalazal region of 

 the ovule, is unable to penetrate it and to reach the micropyle. 



eeds of Leguminosse.|j — L. H. Pammel has studied the structure 

 of the seed in a very large number of genera and species of Legu- 



• Bull. Torrey Bot. Club, xx^ii. (1900) pp. 589-92. 



t Mutti rerde, ii. (1900) p. 417 (1 fig.). See Bot. Centralbl., lxxxiv. (1900) p. 294. 



J (Esterr. Bot. Zeitschr., 1. (1900) pp. 383-5. 



§ Jouru. de Bot. (Morot). xiv. (1900) pp. 97-9. 



|| Trans. Acad. Sci. St. Louie, ix. (1899) pp. 92-263 (29 pie.). 



