Dr. A.Braun on the Vegetable IndividuaL 253 



organism. Any single member of a plant (as the internode and 

 leaf) corresponds no more to such a physiological individual than 

 does the cell ; for plants undergo their metamorphoses in their 

 successive members ; and the various processes of their preser- 

 vation, reproduction and propagation are connected with the 

 various steps of these metamorphoses. Nor can it be the shoot ; 

 for that usually does not embrace all the steps of the metamor- 

 phosis; besides, the functions are variously distributed in the 

 shoot; and in many cases, this takes place for the reciprocal 

 completion of the functions. Besides, whatever is characteristic 

 in ramification and in growth depends upon the combined shoots, 

 and without these it is impossible to conceive of trees, for in- 

 stance. Then we come back to the whole plant-stock ! Nay, 

 farther ; we cannot stop at the plant-stock ; for the single stocks 

 are far from being perfect representatives of all the phases and 

 tendencies of the specific life. I would refer to the division ac- 

 cording to gender, or the modes of fructification, which is often 

 made in botany; the dioecious and tricecious* relations, and 

 farther, to the varieties, especially to those which do not possess 

 essential organs and functions, which belong to the species as 

 such ; e. g. those varieties which never bear blossoms (ball- 

 acacias), or which never produce fruit (congested blossoms), or 

 which never perfect seeds (currant-grape, cultivated bananas and 

 bread-fruit trees). Besides, no stock is exactly similar to an- 

 other : we ascertain only the limits of the possible relations of 

 the specific form by a comparison of many stocks. As in ani- 

 mal physiology the solution of the problem of the life of many 

 animals depends upon their social relations (societies composed of 

 couples or of flocks, or of self-governing states), so in vegetable 

 physiology it depends upon characteristic physiological traits 

 whether plants live singly and dispersed, or in societies. For 

 example, in considering the life of turf-mosses, we must deter- 

 mine whether they grow in great sods or in carpets ; and of 

 grasses, whether they form meadows; or of trees, forests. Even 

 the relations of geographical distribution, which are discovered 

 by a comparison of all the stocks, depend upon the physiological 

 character of the plants : plants of sensitive and inflexible consti- 

 tutions are found only within narrow limits; while plants of 

 adaptive and pliant constitutions are more widely distributed, 

 become migratory plants, and by degrees spread over almost all 

 parts of the earth, if their seeds possess the necessary properties. 



* Trioecious plants are exceedingly rare among Phanerogamia {Cera- 

 tonia, some kinds of Rhus), but are more common among the Crypto- 

 gamia3 ; perhaps we may add the Floridie. In Polysiphonia violacea I 

 have found three kinds of stocks mixed, and in the same stage of develop- 

 ment in the same place (upon the same thread in Chorda Filum). 



