The Nature and Origin of Stipules. 17 



The scales of rhizomes are divided into those formed by a de- 

 velopment of the leaf-base (Dentaria, Chrysosplenium) and those 

 formed by a modification of the upper-leaf (Labiatse, Onagraceae). 



Colonih. G. — Note sur l'ochrea des Polygon^es. Bull. Soc. Bot. Fr. 33 : 

 506-507, 1886. 



" The ochrea of the Polygonums is a complex organ formed of 

 two parts : one opposite the leaf, the leaf-sheath, the other in its 

 axil and detached from the petiole. This is a ligule." " Practi- 

 cally the same conditions prevail in the Gramineae as in Poly- 

 gonum with the difference that in the former the sheath proper is 

 greatly developed and little prolonged beyond the insertion of 

 the blade, while in the latter, the sheath proper remains short and 

 is much prolonged above the petiole. B}' union with the ligule it 

 forms an ochrea. So considered the ochrea is not peculiar to the 

 Polygonacese. It is found also in Ficus and Magnolia, establish- 

 ing the transition between the ochrea and stipules properly so 

 called. 



Vuillemin, P. — Apropos d'une recent communication de M. Colomb. 

 Bull. Soc. Bot. Fr. 34: 141-142. 1887. 



Commenting on the preceding paper, the author says that the 

 leaf is primitively unifasciculate. The concrescence of a verticil 

 of elementary leaves, such as occurs in the fossil Aster ophyllites, 

 gave a sheath analogous to that of Equisetum ; the bundle 

 of one of these elementary leaves becoming predominant and 

 functioning as a midvein gave rise to an aggregate leaf, the 

 first stage of a high differentiation. In this way the origin 

 of the leaf-blade in Polygonum, Platanus, etc. is explained, while 

 the ochrea, the homologue of the sheath of Equisetum, remains 

 as a vestige of the primordial state. 



Ivroiifeid. M. — Ueber die Beziehung der Nebenblatter zu ihrem Haupt- 

 blatte. Verhand. der Kais.-Konig. Zool.-Bot. Gesellscbaft Wien. 37. Abhandl. 

 69-79. 1887. 



The author has made investigations experimenting upon a 

 large number of plants, by the removal of the lamina of the 

 leaves at the earliest possible stage of development, in order to 

 observe the effect upon the development of the stipules and so 

 determine their physiological relation to the leaf-blade. Only in 

 exceptional cases was the ultimate size of the stipules increased, 

 and those where the stipules were normally foliaceous. 



