68 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
different part, the cells remaining thin-walled and becoming filled with 
reserve-substances. These substances may be sugars {Yucca), starch 
( Dioscorea , Tamus ), or fatty oils ( Cohnia ). 
Anatomy of the Wood of Albizzia.* * * § — Herr A. Burgerstein describes 
the histological structure of the remarkably soft and light wood of 
Albizzia moluccana (Mimosese) from Java. The xylem has a very simple 
structure, and consists of five elements, viz. : — very thin-walled xylem- 
cells ; large pitted vessels ; wood-parenchyme ; medullary-ray-cells ; 
and septated crystal-fibres. The vessels are so large as to be visible 
to the naked eye. In the crystal-fibres each cell contains a single large 
crystal of calcium oxalate. 
Sieve-tubes of Calycanthus.f — According to Mr. J. L. Williams, 
in young stems of Calycanthus occidentals, the greater part of the phloem 
in the cortical bundle consists of sieve-tubes, these elements being far 
more numerous in the cortical bundles than in the bundle-ring. 
Structure of the Terebinthaceae.J — M. F. Jading has studied the 
anatomical structure of the stem of the Terebinthaceae, in the case of 207 
species belonging to 67 out of the 71 genera. The order is divided into 
the two tribes, Bursereae and Anacardieae. The most constant character 
is the occurrence of secreting canals in the liber, protected by pericyclie 
fibres. Less constant as generic characters are those drawn from the 
anatomy of the stem, and from the presence or absence of medullary 
canals. 
C4) Structure of Org-ans. 
Doubling and Reduction in Flowers. — Dr. L. J. Celakovsky § 
regards the doubling of leaves (including petals and stamens) as always 
the result of an actual increase in the number of parts. 
To this Prof. K. Goebel replies || that this is certainly not the case 
in the branched stamens of the Hypericacese and Loasaceae, where these 
structures are not of foliar origin, but result from the projection of 
divided portions of the receptacle. Such flowers are in fact derived, by 
reduction, from other polyandrous forms. 
Integument of the Seed of Polygalaceae.^ — According to M. A. 
Rodrigue, the testa of the ripe seed is, in this order, derived from the 
inner integument only of the ovule, the outer integument having entirely 
disappeared. The parenchyme of the testa and of the aril, the raphe, 
and the pseudo-raphe have been formed at the expense of the innermost 
layer of the inner integument. When the seed contains endosperm the 
cells of the nucellus have been entirely resorbed. During germination 
the differentiation of the tissues of the embryo commences with the 
formation of the tracheal elements ; then follows the development of 
the conducting elements of the phloem ; next the palisade-parenchyme 
and the chloroplasts of the leaf ; and finally the stomates. Three types 
* Ber. Deutscli. Bot. Gesell., xii. (1894) pp. 170-2, 267-8. 
t Ann. Bot., viii. (1894) pp. 367-70 (1 fig.). 
% Ann. Sci. Nat. (Bot.), xix. (1894) pp. 1-51 (20 figs.). 
§ SB. K. Bohm. Gesell. Wiss., 1894 (5 pis.). 
|| Flora, lxxix. (1894) Erganzungsbd., p. 443. 
Tf Bull. Herb. Boissier, i. (1893) pp. 450-63, 514-41, 571-83 (3 pis.). See Bot. 
Centralbl., 1894, Beih., p. 349. 
