210 DEVELOPMENT OF 



close above one another, which are at the time of flowering 

 already dead. On the lower part of the axis there are from one 

 to three pseudo-tubers ; in the axils of the upper leaves many 

 young lateral axes. Most of the leaves of the highest of these 

 lateral axes, or sometimes of two, which are to flower next year, 

 are, at the time when the peduncle of this year's axis is perfectly 

 evolved, entirely expanded, forming a rosette. The new leaves 

 belong, therefore, to a different axis from that of the peduncle. 

 The pseudo-tubers contain the nutriment for the lateral axes with 

 expanded leaves, and die with the leaves themselves the next 

 summer, at which time new pseudo-tubers are formed on the 

 lateral axis, which then becomes the principal axis at the same 

 time with the axis on which they staud. By the decay of the 

 basal axis, the buds in its lower leaves, and whose leaves are not 

 evolved like those of the upper bud, become free. They put forth 

 pseudo-bulbs, but do not flower till they have borne merely rosettes 

 for many years. 



Spirantues autumnalis. 



Fig. 1. Base of flowering plant. 



a. peduncle. 



b. basal axis. 



c. c'. tuberiform roots. 



d. lowest sheatb of tuft of 



leaves. 



f. accessory bud. 



2. g. rudirnentof largerpseudo- 



tuber. 

 h. smaller do. 

 e. scale in whose axil they 



are produced. 



Platanthem bifolio. 



It is well known that when the plant flowers, there are two 

 pseudo-tubers, the older shrivelled and about to perish, the 

 younger plump and fresh. The older pseudo-tuber has at its 

 upper extremity a larger or shorter appendage, at whose tip there 

 is a scar formed of dead parenchym. This is the point of attach- 

 ment of the peduncle of the previous year, which is now almost 

 entirely decayed. Near this place is seated the peduncle of this 

 year, on an oblique sloping area. The following appearances are 

 observed on its axis : 



1 . A short sheathing scale ; the base of this is perforated by 

 numerous long simple roots, seated round the stem, and confined 

 to that portion of it which is embraced by the scale, and thickly 

 clothed with fine hairs. 



2. A rather long sheathing scale projecting beyond the first, 

 and alternating with it more or less perfectly. It is split behind 

 at the base, and through the fissure protrudes the fresh tuber. 



