1896.] Vegetable Physiology. 



by the plant when it is taken from the plain tc 

 versa, disappear at the end of the same time when the plant is put 

 back into its own climate. Modification of junctions : (1) If a plant 

 grown on the mountains is transported immediately to the level of one 

 grown on the plains (both originally from the same root) we find for 

 the same surface and under the same conditions, the chlorophjllian 

 assimilation and the chlorovaporisation are more intense in the leaves 

 brought from the alpine region ; (2) If the respiration ami the transpira- 

 tion in the dark are compared in the same way, we find that for equal 

 weights these functions have about the same intensity, or are less in 

 the alpine specimens. The paper contains numerous wood cuts show- 

 ing anatomical details and eleven lithographic plates comparing alpine 

 and lowland individuals of the same species. The last is a double 

 plate in color, illustrating tin- brighter hues of the mountain flowers. 

 Foot notes refer to the principal literature. — Erwix F. Smith. 



Spore Formation Controlled by External Conditions. — 

 Einfluss der ausseren Bedingungeo auf die ^porenbildung von Tham- 

 nidium elegans Link, by Johann Bachmann, is the title of the leading 

 paper in Botanische Zeitung for July 16, 1895. Thamnidinm elegans 

 is a graceful little mould bearing two sorts of sporangia. The sporo- 

 phore consists of a slender upright stalk, 2-4 cm. high and usually ter- 

 minated by a single large sporangium, having a columella and bearing 

 many spores. Midway down the sporophore there are usually one to 

 ten or more whorls of branches which ramify dichotomously, often 



ends small sporangia (sporangiola) generally only 6-8 ft in diameter 

 and containing only a very few spores, usually 1-4. Sometimes only 

 the end sporangium develops and sometimes only the dichotomous 

 sporangioliferous branches ; but the cause of this variation which is un- 

 doubtedly what led De Bary into the error of supposing Thamnidium a 

 stage in the development of Mucor, has remained unknown. By vary- 

 ing his culture media Bachmann has discovered that he can at will 

 produce sporophores with or without end sporangia and with or with- 

 out sporongiola ; in the same way he has been able to change the 

 tiny sporangiola, which frequently bear only a single spore, into big 

 sporangia provided with a columella and bearing many spores. As 

 the result of his experiments he divides the fungus into six types as 

 follows : (1) End sporangium present ; sporangiola appearing very 

 early on finely dichotomous branches which may reach the tenth sub- 

 division spores few. This form occured on more than a dozen differ- 



