70 BOTANICAL GAZETTE [january 



tomical characters to systematic research. As a matter of fact, the anatomical 

 characters as described by Viguier are not only verj- useful, but to some extent 

 really necessary for gaining a thorough knowledge of this family and its affinities. 

 From an external morphological point of view the Araliaceae exhibit a number 

 of ver>' conspicuous types, represented by herbaceous, frutescent, and arborescent 

 species; among these the herbaceous are of a special interest, and it is to be 

 regretted that the author could not examine the root structure of the very peculiar 

 Panacineae, for example, to which the ginseng belongs. The stem structure seems 

 to be ver>^ constant. The cuticle is often thick; the epidermis consists only of a 

 single layer; the cortex is differentiated as an external continuous zone of collen- 

 chyma and an inner parench\-matic zone frequently traversed by secretory ducts; 

 ^e pericycle is stereomatic and forms arches, always accompanied by secretory 

 ducts; the cork develops constantly in the peripheral hypodermal stratum of 

 cortex, the only exception being Echinopanax. A \txy considerable variation 

 exists m the occurrence of ducts in the pith, of mestome strands in the pith, in the 

 presence or absence of secretory cells {poches secretrices) in the secondary hadrome, 



^w! '"'^^'^^ ^ ^^^^^^^ noticeable from the anatomical table. The petiole shows 

 also a very characteristic structure, and among the generic characters may be 

 enumerated the arrangement of the mestome in one or several concentric bands; 

 the vanous disposition of the ducts; the coUenchyma continuous or interrupted 

 by cortical, chlorophyll-bearing parenchyma, etc. The structure of the petiole 

 becomes very much complicated when secondary formations set in, as obsen-ed in 

 several species. In the blade of the leaf the structure is quite variable, as foHows: 

 secretory cells occur only in Gilibertia; the midrib may be composed of several 

 mestome strands arranged in a circle, or may consist only of an arch of leptome 

 and hadrome; hypodermal collenchyma is developed in some genera, but not in 

 others^ The anatomical keys are drawn so well that the genera may be easily 

 Identified m a number of cases. Ten tribes are recognized by the author, and 

 some new genera have been proposed. Aralidium has been excluded; it lacks 

 secretory ducts and might be placed more naturally a^ a member of Comaceae, 

 near Tomcellia, -MelanophyUa, and Kaliphora.-TnEO. Holm. 



Embryology of Sechiam.-LoxG0=5 has found that in the maturing seed of 

 bechium (Cucurbitaceae) the outer integument enlarges, consisting of homogene- 

 ous patenchj-ma traversed by vascular strands and rich in starch. No "testa'' 

 development occurs, but the o.-ule is closely invested by the pericarp. The outer 

 integument is thus a food-storage region for the embryo, which uses up the endo- 

 sperm aU ot the nucellar tissue, and the inner integument. In germination the 

 ODnnedons are differentiated into two regions, intraseminal and extraseminal. 

 The stomata of the two regions differ markedly, in the intraseminal region being 

 more circular m outline and with more circular sHts than shown by the decidedly 

 elongated^outfme of guard cells and sUts of the extraseminal region. The differ- 

 entiation IS possibly associated with the differentiation into absorbing and photo- 

 syntheuc regions.— J. M. C. ^ ^ 



-s LoNGO, B., Sul Sechium eduIeSw. R. Accad. Lincei 16:47=^472. figs. 2. 1907- 



