and Growth of Monocotyledons. 183 



points where the leaves pass off from the stem, in the full-grown 

 annual stem. In the Crocus, Tulip, Hyacinth, &c., the leaves 

 arise immediately from the base of the flattened stem situated at 

 the bottom of the bulb ; the fibres of the peduncle of these plants 

 become developed upwards with the growth of the part in which 

 they are placed, their inferior extremities retaining their relations 

 unaltered below. In the Tiger Lily, Crown Imperial, &c., the 

 leaves are borne upon the elongated stem, and in Asparagus 

 branching of the stem takes place ; in this form the lower part 

 of the stem retains the bulb-like character, and the ascending 

 portions of the fibro-vascular bundles become developed upward 

 in the stem before passing into the leaves. 



Such stems, examined without reference to the bulb and in 

 the full-grown state, would be liable to be taken for instances of 

 an endogenous growth, since the fibres of the lowest leaves or 

 branches are most external, and those going to the younger 

 leaves and flowers, situated in the centre ; but by tracing them 

 downward to the base in the bulb, we there find them crossing 

 to get outside the older fibres. Some of the fibres in the upper 

 part of the stem appear to possess no inferior tract ; these may be 

 supposed to originate subsequently during the growth of the 

 flowering-stem, and do not interfere with the general character 

 of the structure. 



In speaking of crossing, it must always be recollected that 

 this term is used rather loosely, as the upper bundles take very 

 variable courses to get to the outer side of the lower ones ; some- 

 times their lower tract is found on the side opposite to that on 

 which they ascend, and they succeed one another spirally, so 

 that it is only here and there that a section will exhibit a direct 

 crossing like that usually shown in diagrams. 



In the above-mentioned plants the annual stem may be re- 

 garded as an inflorescence. In the Grasses and in Trades- 

 cantia we find several internodes in the annual stem ; the fibro- 

 vascular bundles interlace at the nodes, at these points also new 

 fibres arise, and roots are often given ofi^. These nodes may be 

 compared to bulbs succeeding one another upwards at intervals 

 in the stem. In the creeping rhizomata of many Monocotyle- 

 dons we have examples of bulbs thus succeeding one another; 

 only in such cases they are axillary and not terminal, and they are 

 the buds provided for the next year's growth, retained in con- 

 nexion with the old stem instead of being shed like the cloves of 

 true bulbs. In most instances they are sessile one upon another ; 

 but in Sparganium ramosum we have an example of bulbs suc- 

 ceeding one another with internodes developed, and thus we get, 

 in a perennial monocotyledonous stem, an analogue of the annual 

 stem of a Grass or of Tradescantia ; for the principal difference 



