92 THE QUANTITATIVE METHOD IN BIOLOGY 



ence of x^ upon Ai-i, certain properties of x^ being eventtially 

 transmitted to ^ + i.^ 



The quantitative investigation of the primordia of the species 

 X and x^ and of allied species, and a similar investigation of the 

 individuals (cauloms, phylloms and trichoms) produced by the 

 graft might bring us nearer the elucidation of the complicated 

 problems alluded to. 



§ 76.— RAMIFICATION OF THE UNIAXIAL SYSTEM. 

 COMPLICATED CASES (continued). ANNUALS, PEREN- 

 NIALS, BULBOUS PLANTS, SHRUBS, TREES.— The 

 quantitative investigation of annuals, perennials and bulbous 

 plants (Orchis, many Liliacece, AmaryllidacecB , etc.), the rami- 

 fication of which is comparatively simple, may be carried out 

 according to the principles expounded in §§ 73-75. But as 

 often as a large mmiber of bud-generations are united into one 

 specimen a complete analysis of the whole is very difficult, 

 although the theoretical possibility always exists. In such 

 cases we may make a choice among the numerous parts (indi- 

 viduals) which are united into one society (specimen) according 

 to certain CONVENTIONS. 



All the herbaceous perennials and suffrutescent plants pro- 

 duce every year (in our climate) new fertile stems which die 

 after flowering (Solidago, Iris, many Graminece, etc.). For a 

 quantitative description of the species we may limit ourselves 

 to these stems. If two or several stems are produced by one 

 specimen (stock or woody base), it is advisable to take the 

 first stem which is ordinarily (not always) more vigorous than 

 the others and flowers earlier than these. 



In the shrubs and the trees it is somewhat difficult to find com- 

 parable material for the specific description of the primordia 

 of the vegetative parts. More or less satisfactory results 

 may be obtained by taking (if possible) terminal segments 

 (shoots) t at the extremity of main stems, ten or more years old, 

 or terminal segments t^ of lateral branches consisting of succes- 

 sive terminal shoots produced for a period of ten or more 

 years. It may be admitted that such segments t (respectively 

 t^) have developed under social conditions which are approxi- 

 mately the same for each and all. In several species a distinc- 

 tion ought to be made between short shoots (spurs, Kurztriebe) 

 and long shoots (Langtriebe).^ Segments developed at the 



*The specific influence and the possible transmission alluded to are quite 

 independent of the question whether the transmitted properties are fixed in 

 the seeds produced by the graft A + i. 



2 An exact definition of short and long shoots and exact information about 

 the social conditions under which they are produced may be expected from 

 quantitative investigation. 



Certain branches having produced typical short shoots for a number of 



