214 



DEVELOPMENT OF 



meanwhile entirely exhausted and crumpled. The bundles of 

 vessels are in consequence isolated from the parenchym, so that 

 the whole pseudo-tuber appears composed of a number of strings 

 loosely held together by the cuticle. 



The axillary bud, which was already visible last year on the 

 parent bud, protrudes from the axil of its parent leaf, which soon 

 dries up, bursting through it, and the pseudo-tuber, which also 

 has ruptured its envelope, is elongated like a little handle, and 

 diverges slightly from the parent plant. The first and second 

 leaves of this bud are extended by reason of this elongation, and 

 form frequently a tolerably long hollow or covered tube, whose 

 under or dorsal wall is formed by the pseudo-tuber at whose base 

 the other parts of the infant bud are seated. In consequence of 

 this extension, both the first leaves of the bulb soon die. But 

 there are also more normal cases in which the first and second 

 leaves are directly above the inner leaves of the bud. The infant 

 pseudo-tuber becomes spindle-shaped, thickening in the middle, 

 but constantly attenuated above, so as often to attain a length 

 of two inches ; its whole surface is clothed more or less thickly 

 with hairs. Everything now occurs as before. A new bud is 

 formed in the axil of the fourth leaf, which is destined to produce 

 a peduncle after an interval of two years. 



It is not requisite to enter into the opinion broached by 

 Schleiden, that the tuberiform organs belong to the axis : the 

 whole history of their evolution shows that they are really roots, 

 like the accessory roots in Crocus. 



Platanthera bifolia. 



year. 

 m. bundle of vessels from axis. 



Fig. 3. bud with the new bud (a') 

 which is to flower the 

 year after. 

 e. aperture of its sheath. 



Fig. 4. section of the new bud 

 when more advanced, to 

 show the origin of the 

 pseudo-tuber. 



d. parent sheath split into two 



laminae below (n, o). 

 p. young pseudo-tuber. 



e. wall of parent bud. 

 a', new bud. 



Fig. 5. Base of a plant, to show de- 

 velopment of new pseudo- 

 tuber, 

 a', the new bud. 

 n. border of do. 



