6o BOTANICAL GAZETTE 



[JANUARY 



important factor in calling forth rhizoids. Dorsiventrality is fixed in 10-20 hours 

 after sowing and "rests upon the reciprocal relation between determinative co- 

 operating external factors and internal conditions of maturity"— the latter depend- 

 ent In large measure upon the age of the gemmae. The plagiotropic position is a 

 functional relation, influenced by illumination, and resulting from the cooperation 

 of diahehotropism and negative geotropism. Moisture and other variable external 

 factors exercise a far greater influence than diageotropism, autogenous hyponasty, 

 and photepinasty, to which it has been previously referred. As to reproductive 

 structures, they seem to arise only when the plants are brightly illuminated, where- 

 as weak illumination and much moisture permit only vegetative growth. Natural 

 parthenogenesis was not obser\-ed. 



Gyorfpy has had opportunity to study that curious hybrid, Physcamitrella 

 Hajnpei, which has three forms, differing according to the male parent, Physcomi- 

 trella patens^ being in all cases the female parent. One of these is P. patensX 

 Physcomitrium sphaericum; the second, P, patens XPhyscomitrium eurystamum; 

 and the third P, patens XPhyscomitrium pyrijorme, which Gyorffy himself 

 discovered. He has made a comparative anatomical study of the first and 

 third hybrid forms and of their parents. This is a paper that will be useful for 

 the wnter of a comparative anatomy of mosses, but for readers it is wordy and 

 tiresomely detailed, and might easily have been compressed, to Its advantage, 

 into half the space. It seems hardly necessary- in such a paper to describe the 

 form of an archegonium and the mode by which the canal is opened for the sperm, 

 when these do not have any peculiarities; the paper is full of such repetitious and 

 irrelevant matter. This bedns in th^ i^iU wT.iV>> ;. o„ .^..n.^* 



:xam 



a title ought not tobe.- Gyorjfy makes one particularly interesting observation, 

 which IS unportant if true; he figures the spore mother cells as capping the colu- 

 meUa m P. patens. This is contrar>' to Limpricht's observations, and as Gyortfy 

 lays no special stress on the point, it seems doubtful if he appreciated its signifi- 



cance 



In general he finds, as others have done, that the vegetative characters are 

 those of P. patens, while the characters of the sporophyte are intermediate in cer- 

 tain respects. Thus the foot and the external form of the sporophyte of P. Hampei I 

 are those of P. sphaericum, while the internal structure is more like that of P. 

 patens. In P. Hampei III, strangely enough, the form of the capsule is like that 

 of P. Hampet I, though the foot and long seat are those of P. pyriforme. 



Servit discuss the mode of branching of the br\-ophytes," supporting the 

 novel views of Velexovsky," which take no account of the source of branch 



comitrelta 



Hum spkaeric 

 paie 



Gyorffy, I TJeber die vergleichenden anatomischen Verhaltnisse von Pkys- 

 tta patens (Hedw.) Br. et Sch.. PAi;t/-««.Vf,;„«, A,„,-f.._.... /t % t>_:j dl.....,«,„7_ 



(Hedw.) X FhyscornUrium pyriforme (L.)]. Hedwigia 47:1^59. 1907 



-eigungsart der Muscineen. Belhefte Bot. Cent. 

 907. 



KT.F? 



