ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 183 



chief anatomical mark is the greatly developed sylem, the chief elements 

 in which are very numerous prose nchy ma tons cells (" libriform cells ") 

 with the appearance of bast fibres, having imperforate transverse walls 

 often so thickened that the lumen is almost obliterated. After a time 

 the soft parts of the leaf are shed, leaving the persistent xylem in the 

 form of a spine. The xylem proper consists of tracheae frequently 

 accompanied by tracheides, especially at the ends of the nerves. Bast 

 fibres always accompany the leptom in some part of its course, though 

 in some species they are found only at the base of the leaf. The species 

 of the sub-genus Inermia have a much less strongly developed xylem, and 

 the leaf-base is either without libriform cells, or, if present, they run 

 isolated from one another. In this sub-genus the leaf is shed as a 

 whole, and consequently there are no spiues. 



In all species the stem consists of cork, cortical parenchyme, phloem, 

 xylem, and pith. The cork is sometimes greatly developed, and the 

 walls of the cortical parenchyma are of pure cellulose. Bast fibres are 

 in small bundles, or form a complete ring on the outer side of the 

 phloem. The xylem is made up of tracheae, tracheides, and libriform 

 elements ; but at the tips of the branches the hadrom forms no com- 

 plete ring, but usually appears as four bundles surrounded by fundamental 

 tissue, bundles from which the leaf-traces originate. One species {A. 

 nanum Engl.) has its xylem always separated into five masses, with 

 medullary rays between. The 4-6 innermost cell-layers of the capsule- 

 wall consist of isodiametral lignified cells (sclereides) with radial walls. 

 This is the conducting tissue, and is accompanied on its outer side by 

 bundles of libriform elements. The sclereides swell up in water, and in 

 consequence of the resistance offered by the libriform bundles, the 

 capsule opens. 



Feh'ostomum, with six species, inhabits the Cape, the extra-tropical 

 part of German S.W. Africa, the Kalahari Desert, Transvaal, Orange 

 River Colony, and Natal. The leaf -structure is much like that of 

 Aptosimum, but the hadrom is semilunar, with a small crescent of 

 leptom on its underside. The hadrom consists of tracheides, with 

 woody parenchyme in some species. There is usually no special 

 mechanical tissue here. In the branches is a more or less broken ring 

 of bast fibres at the outer border of the leptom. The xylem consists of 

 trachea;, tracheides, and wood prosenchyme. Sections at the base of a 

 branch show the same structure as at the tip. The capsule has no 

 libriform cells in its wall, and it does not open hygroscopically. 



The rest of this excellent memoir is devoted to detailed examination 

 of the several species. 



Reproductive. 



Reproduction of the Fig Tree.* — Leclerc du Sablon has investi- 

 gated the two kinds of flowers of the Fig tree (Gcqjrificus), with special 

 reference to their symbiotic relationship to Blastaphaga. The author 

 finds that, contrary to previous ideas, not only do the autumn figs form 

 seeds, V)ut also those produced in winter. The formation of seeds by 



* Comptes Rendus, cxliii. (1906) i^p. 756-7. 



