452 SUMMARY OF CURRENT RESEARCHES RELATING TO 



more or less condensed and fleshy ; the roots are generally of two sorts, 

 long surface ones for rapid absorption of moisture, and short deeper ones 

 for support. As regards the fruit, from the study of many species from 

 the stain! point of structure, from the similarity in external appearance 

 between the fruit and the ultimate vegetative branches, and from terato- 

 logical evidence, the author concludes (1) that the fruit is caulome in 

 structure ; (2) Its caulome nature is probably of recent development ; 

 (3) It has become caulome by its once superior ovary receding into a 

 vegetative branch, thus making it at present inferior ; (4) The branch, 

 winch now becomes the ovary, is usually modified and ripens into the 

 structure which we term the fruit. It may, however, become but little 

 modified, resembling the ultimate branches, and continuing as a vegetative 

 part of the plant. 



Throughout the genus the fruit in its early development bears 

 numerous leaves in the axils of which vegetative branches as well as 

 flowers occur. The fruit of the flat-stemmed species deviates farthest 

 in form from that of the normal vegetative branch ; but in several of 

 these the structure containing the seeds is sometimes large and flattened, 

 like the normal vegetative branches. In such cases, however, the whole 

 member does not become pulp-like, change colour and ripen. Only that 

 part immediately surrounding the seeds ripens as the seeds mature ; the 

 remainder continues as a vegetative part of the plant. When the fruit 

 is sterile it often does not ripen at all, but remains on the plant for 

 months after the normal fruits have matured. These sterile fruits some- 

 times produce normal flattened branches during the second season. 



Ponzo. V — L'autogamia nelle piante fanerogame. (Autogamy in seed-plants.) 



[Inclndi s reservations on species of Ranunculus, Matthiola, Brassica, Gypso- 

 phila, Silene, Calendula, Linaria, Satureia, Euphorbia, Crocus, Narcissus, 

 and Scilla.'] Bull. Soc. Bot. Ital, 1905, pp. 73-87. 



Physiology. 

 Nutrition and Growth. 



Soi Inoculation for Leguminous Plants.* — G. T. Moore has made 

 an important contribution to our knowledge of the behaviour of nitro- 

 genous fixing organisms, and one of considerable economic value. He 

 finds hat the nitrogen is fixed by the tubercle-forming bacteria within 

 their bodies. This was determined by cultures in flasks containing 

 nutrient solutions without nitrogen, when no increase of nitrogen was 

 founil in the solution, but a marked increase in the organisms themselves. 

 The organism is therefore a parasite. Ultimately the plant overpowers 

 the parasite, and uses the fixed nitrogen. Grown in nitrogenous media 

 the oi.; hi ism lost both its power of infecting leguminous plants and its 

 power of tixing nitrogen ; whereas in non-nitrogenous media both these 

 propei ties were retained. A lack of recognition of these facts serves 

 probably to explain previous failures by Nobbe to obtain for economic 

 use pine cultures of this organism. The author has devised a method 

 of pui i in • up for distribution pure cultures of Pseudomonas radicicola, 



* V . D.i t of Agric, Bureau of Plant Industry, Bull. 71 (1905) 72 pp., 10 pis. 

 See also Bot. Gazette, xxxix. (1905) pp 371-2. 



