SPECIAL FORMS. 



63 



121. A Tunicated or Coated Bulb (Fig. 113-115) is one in 

 which the scales are broad and completely enwrapping, forming 

 concentric coatings. These are thickish when fresh, but thin 

 when exhausted and dry, as in the Onion, Garlic, and Tulip. 



122. A Scaly Bulb 

 has the bulb-scales 

 comparatively nar- 

 row, thick, and small, 

 imbricated, but not 

 severally enwrapping 

 each other. That of 

 the Lily is the most 

 familiar and char-, 

 acteristic example. 

 (Fig. 118, 119.) 



123. Bulblets are small aerial bulbs, or buds with fleshy scales, 

 which arise in the axils of the leaves of several plants, such as 

 the common Lilium bulbiferum and 



L. tigrinum, the Tiger Lilies of the 

 gardens (Fig. 120). Here they ap- 

 pear during the summer as axillary 

 buds : they are at length detached, 

 and falling to the ground strike root, 

 and grow as independent plants. In 

 the common Onion, and in many other 

 species of Allium, similar bulblets 

 take the place of flower-buds in the 

 umbel. Bulblets plainly show the identity of bulbs with buds. 



124. All these extraordinary, no less than the ordinary, forms 

 of the stem, grow and branch, or multiply, by the development 

 of terminal and axillary buds. This is perfectly evident in the 

 rhizoma and tuber, and is equally the case in the corm and bulb. 

 The stem of the bulb is usually reduced to a mere plate (Fig. 

 114 a), which produces roots from its lower surface, and leaves 

 or scales from the upper. Besides the terminal bud (c), which 

 usually forms the flower-stem, lateral buds (b, b) are produced 

 in the axils of the leaves or scales. One or more of these may 

 develop as flowering stems the next season, and thus the same 

 bulb survive and blossom from year to year ; or these axillary 

 buds may themselves become bulbs, feeding on the parent bulb, 

 which in this way is often consumed by its own offspring, as in 



120 



FIG. 118. Scaly bulb of Canada Lily. Lilium Can ad en se, after flowering, 

 tical section of same, showing two new young bulbs within. 



FIG. 120. Bulblets in the axil of the cauliue leaves of Tiger Lily. 



119. Ver- 



