Francis E. Lloyd — 134 — Carnivorous Plants 



Wounding, necessary in such plants as Begonia (Goebel 1903), in 

 itself is of no influence (Behre). It has been thought that the removal 

 of the chief shoot (particularly the growing shoot) is a stimulus, that 

 is to say, the disturbance of correlations (Behre), which is attained 

 simply by the removal of the leaf. The weight of this point seems not 

 to be great since budding occurs in abundance on leaves still attached, 

 in the case of D. peltata, though rather more slowly than when the 

 leaves have been removed (Vickery). When some of the glands have 

 been injured or removed, the leaf will still produce buds, but only from 

 the bases of uninjured glands (Vickery), indicating that the gland may 

 contribute something in the form of a growth substance (see Coe- 

 LiNGH 1929). 



Nevertheless Behre did find certain correlations. The removal of 

 the growing point always increased the leaf budding, though em- 

 bedding it in gypsum plaster did not. If the removal of the growing 

 point incited the development of an axillary bud, this itself would 

 inhibit bud formation, though if at the same time the vascular tissue 

 had been suitably cut, before the axillary bud was put into activation, 

 buds were formed. Behre further did this experiment: after removal 

 of the growing point the leaves were cut longitudinally in some cases 

 and transversely, but not sufhcient for amputation, in others. Only 

 on the outer parts of transversely cut leaves did buds arise, while on 

 plants similarly treated but with the growing point not removed, the 

 result was negative. Yet Behre recorded the occurrence of an ad- 

 ventitious bud on a leaf on a plantlet, itself produced adventitiously 

 from a scape, with the growing point active (1929, Fig. i). These results 

 with D. rotundifolia could not be obtained with D. capensis. But the 

 facts as they stand support the view that there is a delicate inter- 

 relation between the growing point and the inclination to regeneration 

 (Goebel) as observed in numerous other plants. Thus we are led to 

 consider what the internal conditions in the plants may be which de- 

 termine or control such phenomena. Here the food materials may 

 play a role or hormones may act as regulators, but this question is too 

 far away from our present purpose, though it may as well be pointed 

 out that Behre did experiments in which he reduced leaves to a con- 

 dition of pronounced hunger in darkness with the deprivation of CO2 

 and yet obtained regeneration, from which he concluded that "there 

 is no doubt that regeneration is put into activity by some other stimu- 

 lus than a surplus of nutrient materials," thus indicating the presence 

 of specific substances, hormones perhaps, which could procure the 

 results. 



Polarity. — The fact of polarity is one of so general observation 

 that Behre naturally raised the question in regard to Drosera, finding 

 but little evidence that it obtains, except to a slight extent in the case 

 of D. capensis and D. filiformis. Adventitious buds are not related in 

 position to the stronger vascular strands, but are found scattered in- 

 differently, arising usually from the abaxial surfaces of tentacle bases, 

 though they may be found on the side or on the adaxial aspect. If 

 small pieces of the leaf blade are made, more buds arise than would 

 otherwise, and even on the leaf margin where they do not occur except 

 when a narrow band (i mm. broad) is made by a cut parallel to the 



