ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
83 
large amount of water in tlie regions of the cortex and young wood in 
the spring. This leads both to an increase in size and to a multiplica- 
tion of the cells, not in the leaves only, but also in the wood ; and from 
this results the great difference in the diameter of tracheids of the same 
annual ring formed in the spring and in the autumn. The production of 
sclerenchymatous tissue takes place chiefly in the late summer and 
autumn. 
Herr G. Haberlandt * claims priority for the more important of these 
observations. 
Course of the Fibres in Wounds, j — Dr. C. Maule has investigated 
the changes which take place in wood in consequence of wounds, and 
especially the very complicated and often apparently irregular arrange- 
ment of the fibres. These phenomena appear to be determined chiefly 
by two factors — the stretching of the elements of the wood connected 
with the wound, by which the course of the bundles is determined in a 
general way ; and the polarity of the cells, which affects the course of 
the individual fibre. 
Stem of Bromeliacese.J — Sig. H. Eoss records the fact that in the 
stem of certain Bromeliacese ( Bromelia fastuosa, Quesnelia cayaunensis) a 
secondary thickening takes place similar to that which occurs in the 
arborescent Liliacem. The generating zone is formed outside the region 
of the vascular bundles, new bundles proceeding from it to the funda- 
mental parenchyme. 
Phloem-Bundles in the Boot of Cyperaceae.§ — M. G. Chauveaud 
finds the root of Cyperacese to agree in structure with that of Gramineae, 
in possessing two kinds of sieve-tube, one developed directly, the other 
indirectly, derived from a group of phloem-cells. This is especially 
illustrated in the case of Eleocharis jpalustris. 
(4) Structure of Organs. 
Antidromy.|j — Mr. G. Macloskie points out the frequent occurrence 
of this phenomenon in plants, displayed in a variation of the arrangement 
of the organs within the embryo. In one kind, the lowest foliage-leaf has 
the right margin of its sheath overlapping the left margin, or infolded 
dextrally; while the other is infolded sinistrally, or has the left margin 
overlapping the right. This results in a variation in direction of the 
line of phyllotaxis (to the right or to the left). It is universal in 
Gramineae ; and a large number of instances are given in other natural 
orders. A similar variation occurs in the inflorescence ; e.g. in Spi- 
ranthes and CEnothera , where the inflorescence sometimes curves to the 
right, sometimes to the left, 
Seasonal Dimorphism.^ — Prof. E. v. Wettstein gives illustrations of 
the occurrence, in the same genus, of two nearly allied species, one of 
which blossoms early, the other late in the year. He regards this as 
* Tom. cit., pp. 337-8. 
f Biblioth. Bot. (Luerssen u. Frank), Heft 33 (1895) 35 pp. and 2 pis. 
I Bull. Soc. Bot. Ital., 1895, pp. 195-6. 
§ Bull. Soc. Bot. France, xlii. (1895) pp. 450-1. Cf. this Journal, 1895, p. 445. 
|| Bull. Torrey Bot. Club, xxii. (1895) pp. 379-87. 
^1 Ber. Doutsch. Bot. Gcsell., xui. (1895) pp. 303-13 (1 pi. and 2 figs.). 
