THE EFFECT OF GROWING SHOOTS ON ONE ANOTHER. 505 



lateral shoots are dorsi-ventral, grow horizontally, and become branched right and 

 left chiefly in a horizontal direction. A similar relation, however, also exists between 

 the various shoots of a whori : if these are equally strong among themselves they 

 all rise up after the removal of the apex, but usually the strongest overcomes the 

 others and obtains the mastery which the true apical shoot exerted previously. In 

 the Red Pine, however, it happens not seldom that after the removal of the apex of 

 the main stem two or even three lateral shoots develope into complete apical shoots. 

 Much less plastic in this relation is the Fir Ah'es pectinata, and probably also 

 some of its nearest allies. I have often removed the apical shoot from young trees 

 of this species, but only seldom, after two or three years, has one of the uppermost 

 lateral shoots erected itself to develope into a new apex. It is more commonly the 

 case with this Fir, that close beneath the place whence the apical shoot has been 

 cut off, or even from the upper side of the base of the nearest lateral shoot, small, 

 previously unnoticed dormant eyes begin to put forth shoots, sometimes not until 

 1-2 years after the removal of the apex, of which one then usually grows more 

 vigorously than the others, and in the course of years is transformed into a new 

 radially constructed apex. 



Very similar mutual relations between main stem and branches also exist in 

 other wood-plants, and especially many forest-trees, and are made use of in various 

 ways in forestry, and especially in the art of felling timber, in order so to interfere 

 artificially with the process of growth as to promote the development of certain buds 

 and to suppress that of others : exactly the same occurs, however, also in small 

 herbaceous plants and even in seedlings. If, for example, the common Scarlet 

 Runner (Phaseolus multiflorus) is allowed to germinate till the primary root is about 

 10-12 cm. long, and the young germinal shoot between the two cotyledons, the 

 so-called plumule, is then carefully cut off, then, as the root-system increases in 

 strength and activity, vigorous shoots grow out from the axils of the two cotyledons. 

 These shoots do not usually develope in this plant, because as a rule the normal 

 primary shoot attracts to itself the whole of the supply of nutriment from the 

 seed, so far as it is suited for the formation of leaf-shoots. In our experiment, 

 on the contrary, the shoot-forming substances of the seed penetrate into the growing- 

 points in the axils of the cotyledons and cause them to sprout vigorously. Not rarely, 

 however, an abnormality makes its appearance here; these vigorously growing 

 axillary shoots of the cotyledons exhibit so-called fasciations — i. e. the shoot-axes 

 become broad and band-like, and crooked, and still other abnormalities occur. 

 Since fasciations not rarely occur in plants of the most different kinds — 

 e.g. in Willows, Compositae of the Camomile group, &c.— it is at any rate of 

 some interest to know that it is also possible to produce such abnormalities 

 artificially. 



Goebel, a few years ago, in his ' Beitrdge zur Morphologic und Physiologie des 

 Blaties'^^ supplied copious and well considered experimental material respecting 

 correlation of growth i, but I must rest satisfied with shortly reproducing here a few 

 only of his results. Goebel's researches are chiefly concerned with the correlations 



' Goebel, 'Beitrdge zur Morphologie und Physiologie des Blattes' (Bot. Zeitg. 1880, p. 753, &c.). 



