THE STEM. 27 



also sometimes visible. Finally, on examining the axil of the innermost 

 green leaf of the present year, we find, nestled between it and the base of 

 the flower-stalk, the bud which is to form the axis of the next year. 

 Therefore this bulb possesses structures or axes belonging to four distinct 

 generations. The bases of the green leaves expand into fleshy sheathing 

 coats after the flowering of the axis which gives rise to them ; and the 

 decay of their blades, which extends to the summit of the bulb, gives 

 rise to the ragged or bitten-off appearance of the latter. These bulbs are 

 postventitious like the last kind, but may be distinguished from them as 

 itidefinite. 



Corm. The corm more or less resembles a bulb externally, but 

 consists principally of a stem with little-developed internodes, 

 thickened into a fleshy body, and bearing leaf-buds at one point, 

 either at the summit, as in the Crocus (fig. 18), or at the side, as in 

 Colchicum. 



The corm of a Crocus examined very early in spring exhibits a primary 

 axis in the form of a roundish mass bearing the adventitious roots below, 

 and giving rise above to one or several tufts of leaves. The bases of 

 the leaves, outside which are a few membranous scales, being at first 

 sunk in the parent axis, these tufts or rudimentary branches are not 

 readily distinguished as secondary axes ; but the -. , g 



terminal bud soon grows out to produce the flower. * 



After the flowering is over, the internodes be- 

 tween the scales and the bases of the green leaves 

 become developed both vertically and also hori- 

 zontally, so as to convert the base of each flower- 

 ing stem into a new corm. When about half- 

 grown the new corins stand out as globular bud- 

 like structures on the top of the old corm, which 

 is gradually exhausted, and decays away, so as 

 to set its progeny free. In the axils of the upper- 

 most leaves of the flowering stem are developed 

 new buds (which exist even before the corm be- Corm of the Garden Crocus, 

 gins to sprout in spring) j and as the new corms cut through perpendicu- 

 are perfected, the buds imbedded in their summits iarl y- 

 form the rudiments of the leaves and flowers of the next season, sprout- 

 ing out in the spring, each to reproduce a corm. Hence in a corm taken 

 out of the ground a short time after the flower withers, we find three 

 sets of axes : 1, the withering parent corm ; 2, the young corms branching 

 from this, formed from the bases of the flowering stems : and, 3, the 

 axillary buds of the leaves of the latter, forming the resting buds at the 

 summits of the new corms. 



In Colchicum autumnale the conditions are somewhat different. When 

 the plant is flowering, in autumn, we find the flowering stem attached to 

 the side of the base of the corm ; the flowering stem is surrounded at its 

 base by sheathing scales and rudimentary leaves ; in the axils of the two 

 lowest leaves exist minute buds, and the internodes between these leaves 

 are slightly developed. The flowering stem then withers down to the 

 ground, and during the winter the internode between the two buds swells 



