290 MORPHOLOGY. 



very insignificant and accidental one), as above given, by close compari- 

 son of the shoots and stems of the Italian Poplar and the black Poplar 

 through all their steps. My knowledge goes no further, and there is 

 here again a hiatus, which certainly would have been partly filled up 

 already, had the time spent in useless ratiocination and writing about 

 these objects been rather applied to true investigation of nature. 



2. Propagative Buds. 



a. Bulbs (bulbi) are Monocotyledonous stems, with undeveloped 

 internodes, which gradually die away from below upwards, and 

 therefore remain always very short, with perennial leaves, whose 

 vaginal parts die away and enclose as thin membranes, the sheaths 

 of the inner leaves still living, and always fleshy and thick (bulb 

 scales), or more rarely die away speedily and leave bare the latter, 

 as in Lilium. They are formed either immediately from the em- 

 bryo, and then the sheathing part of the cotyledonary leaf becomes 

 the first bulb scale ; or they are formed from the axillary buds of 

 the bulb, or from the axillary buds of the stems which have sprung 

 from the bulbs, as in Lilium bulbiferum : less frequently they are 

 from adventitious buds on leaves or other parts. We distinguish : 



A. The leafy bulb (bulbus foliosus). 



1. The tunicated bulb (b. tunicatus), where many sheathing parts 

 are closed round, or embrace the axis pretty broadly, as in 

 Hyacinthus orientalis. 



2. The scaly bulb (b. squamosus), where many sheathing parts, 

 relatively slender and short, are seated on the axis, as in Lilium 

 candidum. 



B. The solid bulb (b. solidus), when the bulb is formed of one 

 single living sheathing part. 



So far as my knowledge extends, no Dicotyledonous plant presents a 

 true bulb, although there is nothing impossible nor improbable in such 

 a thing ; since if we disregard the character of the undeveloped inter- 

 nodes, and thus make the definition more general, the subterranean stems 

 of Lathrcea squamaria, Dentaria bulbifera, etc. are bulbi squamosi. I 

 would, however, the less recommend such an innovation, since the dis- 

 covery of a true Dicotyledonous bulb would make the definition pro- 

 posed appear more to the purpose. Another question is, whether we 

 shall reckon the bulbels of some of the species of Oxalis here. I have 

 not myself found opportunity sufficiently to examine them, and therefore 

 leave them for the present among Dicotyledonous bulbels, since I make 

 the persistence of the bulb, as such, a character of its definition. On the 

 other hand, it is quite incorrect to separate the axillary bulb of Lilium 

 bulbiferum from bulbs : since it is a bulb in its structure, it always re- 

 mains a bulb, and it is formed in the axil of a leaf of a bulbous plant, 

 whether on the stem or the stalk, appears to be quite unimportant. 



The three divisions of bulbs which we have given are practical sub- 

 divisions of bulbs, as such, according to their composition out of the 

 parts necessarily present to make them fall within the definitions. 



It is inconceivable to me how the reticular bulb can be arranged as 

 A 3., simply because in some tunicated bulbs the external decaying coats 

 become at last fibrous. If this mode of classification were correct, we 



