Nos. 620-621] JOAN BAPTIST A PORTA 



adapted also to live in the water. In several chapters 

 descriptions are given of the habits of plants, of species 

 characteristic of the mountains, the lowlands, the hill- 

 sides, and the shady valleys; to these were added some 

 brief remarks upon the vegetation of the northern, the 

 temperate, and the torrid zones. Among the cultivated 

 plants Porta mentions Zea, which, however, is not the 

 plant known now under this name (maize), but a kind of 

 wheat (Triticum Spelta) as demonstrated by De Can- 

 dolle. In bringing these facts together Porta certainly 

 laid the foundation of plant ecology, and the classifica- 

 tion, proposed by Warming (I. c), of the various plant 

 societies: "Hydrophytes, Xerophytes, Haloplujtes and 

 Mesophytes" is not much more instructive than the one 

 introduced by Porta: ''plants? palustres, fluviatiles, mar- 

 ina?, salsa? aqua?, silvestres," etc. 



Naturally these groups have received a more elaborate 

 treatment by authors of a recent date, especially with 

 reference to the internal structure, which often, but very 

 far from always, is in correlation with the respective en- 

 vironment. However, the weakness of modern ecology 

 rests on the belief that the structures may be explained 

 as caused by the natural surroundings. Experience has 

 taught that the genera and species do possess some char- 

 acter of their own, which they never give up. To a cer- 

 tain limit the plants may allow themselves to submit to 

 changes, but beyond that they will sooner die. 



So far as Porta considered the biologic question of 

 plant life, dealing only with the superficial aspect, more 

 or less comparable to the surroundings, he committed no 

 errors of consequence. For as a matter of fact the prin- 

 cipal features exhibited by members of plant societies 

 are mainly external, such as the shape of leaves, their 

 relative size, the organs of vegetative reproduction, and 

 the general habit ; the internal structure cannot be relied 

 upon, at least not at the present stage of our knowledge 

 of plant life. 



Thus already in the sixteenth century the first essay on 

 plant ecology appeared, and Porta was the author. 



