266 INFLUENCE OF CORRELATION AND EXTERNAL STIMULI 



from cells rich in salt than from cells which do not contain so much l . 

 We see consequently that many plants which become flooded with salt 

 water place their leaves in the profile position, like plants subjected to 

 strong insolation, in order to provide a protection against too strong 

 evaporation. Here, however, the question is how far the relationships of 

 configuration of the halophytes are directly caused by the life-relationships. 

 As in other groups, we find amongst them plants whose configuration is 

 fixed, and even under diverging conditions is not changed, at least not in 

 the first generation ; and again there are plants in which such a change does 

 take place. Thus many plants, like Lotus corniculatus, Plantago major, 

 Atrlplex rosea, Blitum polymorphum, Scrophularia frutescens, produce on 

 the shore more fleshy leaves than they do when grown inland, whilst the 

 leaves of Salsola Kali, Halogeton sativus, and others, are thinner when the 

 plants are growing upon a soil without salt, than is usual on plants growing 

 on saline ground. 



Lesage ' 2 has carried out a series of experimental cultivations which show 

 that in some plants, Lepidium sativum, for example, the succulence of the 

 leaf depends upon the possession of salt ; when this condition exists the 

 palisade-cells are especially strongly developed, the intercellular spaces are 

 less conspicuous, the chlorophyll-corpuscles are not numerous, and the 

 whole plant remains stunted. 



3. FUNGI. 



The influence of nutrition upon many fungi is most characteristic. 

 Several of the facts bearing upon this subject have already been mentioned 

 in the chapter upon malformations, here we have only to do with effects 

 upon the ' normal ' sequence of development from which of course the 

 abnormal is not sharply separated. 



If the zygospore of Mucor, richly filled with reserve-material, be 

 allowed to germinate in the air, it forms no mycelium but a germ- 

 tube which ends with a sporangium (Fig. 129); but if germination takes 

 place in fluid, a mycelium arises, upon which numerous sporangia 

 subsequently appear. The formation of these sporangia however can 

 take place only in the air, not in a fluid, according to Brefeld. The 

 ' gemmae,' which are cells rich in contents, developed under definite 



1 Stahl, Einige Versuche iiber Transpiration nnd Assimilation, in Botan. Zeitung, 1894, p. 117. 

 Stahl found that in plants which are not ' halophilous ' the stomata are closed by the absorption of 

 common salt, and he concludes that this is why our ordinary plants do not appear upon the seashore. 

 1 believe however that there is something more operative here and that the salt itself has a direct 

 harmful influence. Most submerged Spermaphyta do not thrive in water which is even slightly salt. 

 The fact that the stomata remain open in halophytes seems to me to indicate only their want of the 

 usual mechanism for regulating transpiration. 



- Lesage, Recherches experimentales sur les modifications des feuilles chez les plantes maritimes, 

 in Revue gencrale de Botanique, ii (1890). 



