308 Morphologie etc. — Varietäten etc. 



almost entirely upon an examination of herbarium material. The 

 main conclusions which he reaches are as follows: 



In Galium and other allied genera, each stipule as a rule de- 

 velops from a Single primordium. Fairly frequently, and particularly 

 in four-membered and rarely in five-membered whorls, stipules 

 may be found which have been produced as the result of a coales- 

 cence of two priraordia. Stipules of this kind (= double stipules) 

 possess either a forked midrib or two separate midribs, the apex 

 of the stipules being at the same time more or less two-lobed. In the 

 seedlings of several species examined of the genera Galium, Aspe- 

 rula, Crucianella and Mericarpaea the node, or sometimes a few 

 nodes succeeding the cotyledonary node, as a rule bear a four- 

 membered whorl, consisting of two true (opposite) leaves and two 

 stipules alternating with the former. In the higher region of the 

 Stern the number of members in a whorl may in some of the species 

 examined be gradually increased up to eight. 



The four-membered whorl is considered and represents the pri- 

 mitive type, at the same time indicating the probable character 

 which prevailed among the direct ancestors of the Stellatae. The 

 six-membered whorl, which probably represents the type that cha- 

 racterized the ancestors of the Ruhiaceae, is in the Stellatae regar- 

 ded as having been derived from a four-membered whorl by com- 

 plete fission (dedoublement) of the two stipules into four. Whorls 

 with more than six members have no doubt originated b}'' repeated 

 fission of the original two stipules. 



Didymaea mexicana, Hook, fil., which bears two opposite leaves, 

 and from two to often six, or rarely seven, scale-like stipules at 

 each node, is presumed to approach the prototype of the Stellatae. 



Galium paradoxum , Maxim., which bears two leaves and two 

 scale-like stipules at the lower nodes and two true leaves and two 

 leaf-like stipules in the higher region of the stem, is believed to 

 be the most primitive species of the genus in this respect. 



Agnes Arber (Cambridge). 



Briggs, L. J. a n d B. L. Shantz, Influence of hybridization 

 and cross-pollination on the water requirement of plants. 

 (Journ. agr. Research. IV. p. 391 — 402. 1 pl. 1915.) 



Versuchsobjekt war ein neuer chinesischer Maistypus mit hohem 

 Wasserbedarf und eine mexikanische Sorte, die gegen Trockenheit 

 widerstandsfähig ist, ferner eine Kreuzung zwischen Triticum durum 

 und T. nestivum. Unter „Wasserbedarf" versteht Verf. das Verhält- 

 nis des Gesamtgewichts der von der Pflanze während ihres Wachs- 

 tums absorbierten Wassers gegenüber der insgesamt erzeugten 

 Trockensubstanz, mit Ausnahme der Wurzeln. Die Resultate wa- 

 ren: Die Bastarde haben einen unter lO*^/,, grösseren oder unter 

 IO^/q kleineren Wasserbedarf als die Eltern. Ein Bastardmais ver- 

 langt oft nicht mehr Wasser als + 6% des Durchschnittsquantums 

 seiner Eltern. Die Kreuzbestäubung zwischen Einzelexemplaren von 

 Mais liefert ähnliche Ergebnisse wie die Bastardierung verschiedener 

 Linien, wenigstens bezüglich des Wasserbedarfes und des Ertrages. 

 Ein Bastard weizen hat nach mehreren Generationen um H^/o höhere 

 Wasseransprüche als der Durchschnitt der Abstammungslinien. 



Matouschek (Wien). 



