Physiologie. — Eumycetes. 101 



and the needles are almost indifferent to gravitation, farther non- 

 twining shoots from rhizomes (10—60 cm), bend the Upper one- 

 third or one-half of the shoot to the horizontal, while branohes of 

 all Orders including needles take the same horizontal, diageotropic 

 Position; lastly twining shoots from the rhizomes (40— 60 cm), 

 and then begins to. twine, rising from one to several meters, finally 

 bending the apical 10—15 cm over into the horizontal position, at 

 the same time unfolding buds along the spiral stem and along the ter- 

 minal horizontal position, the branches of all Orders taking the hori- 

 zontal, diageotropic position. Though all kinds of shoots are positively 

 heliotropic, the direction of the light has nothing to do with thedeve- 

 lopment of diageotropism, except that it may determine the plane 

 of the diageotropic curve, by first causing a heliotropic curve, and 

 this giving gravitation of footing for the development of diageotro- 

 pism. There is no evidence of geonasty or photonasty. Growing 

 shoots, revolved about the horizontal axis of the klinostat, develop 

 to maturity with no indication of diageotropism. When the aerial 

 shoot becomes diageotropic and horizontal, it is still in morphology 

 and physiology radial. The elongation of the aerial shoot is brought 

 to an end by the action of light. In the dark, growth seems capable 

 of continuance as long as food lasts. Only in seedling shoots do 

 the lateral buds unfold in the dark. The unfolding of lateral buds 

 on the normal shoot seems to be phasogenic, but cannot be caused 

 by the inception of diageotropism. The assumption of the diageotro- 

 pic Position by the apex of the shoot cannot be conditioned by the 

 unfolding of the lateral buds; the assumption of the plagiogeotropic 

 Position by seedlings.in the dark, and to a less degree by other 

 shoots never exposed to light, has become hereditary. The presence 

 of light is necessary for the development of circumnutation, and 

 hence for twining, The biological significance of various behaviors 

 of Asparagus may be referred to the conservation of building ma- 

 terial. The significance of the bending to the horizontal of the upper 

 third or half of the aerial shoot from the rhizome and of the seed- 

 ling may possibly bring the assimilating part of the plant into 

 greater light. Matouschek (Wien). 



Tröndle, A., Neue geotropische Versuche. (Verh. Schweiz. 

 Naturforsch. Ges. II.'p. 215— 217. 1913.) 



Die für die Abhängigkeit der Reaktionszeit des Prozesses Ein- 

 fluss des Lichtes auf die Aenderung der Permeabilität der Plasma- 

 haut von der Intensität des Lichtes vom Verf. gefundene Formel 

 i(t— k) = i(t'— k) gilt auch für die heliotropischen Reaktionszeiten 

 der am Orte vorbelichteten Keimlinge (Pringshe im), für die 

 geotropischen Reaktionszeiten (Bach). Sie stimmte nicht bei den 

 letztgenannten Zeiten, die Pekelharing bei Avena feststellte. 

 Daher unternahm Verf. neue Versuche mit den Koleoptilen der 

 Avena, wobei er seine obige Formel aber bestätigt fand. 



Matouschek (Wien). 



Stevens, F. L., The genus Meliola in Porto Rico. (Illinois 

 Biological iMonographs. II. 4. p. 86. pl. 1 — 5. Apr. 1916. — Issued 

 July 17. 1916. The University of Illinois.) 



One hundred and one species and varieties are enumerated for 

 the island, on 171 host-plants. The following 62 are described as 

 new: Meliola glabra Psychotriae, M. sepiilta Patouill. ined., M. irre- 



