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Elementary Work in Botany. 



Fig. 33. Tubers of Scutellaria tuberosa. 

 a. The old tuber which has given up its 

 starch to feed the above-ground stem in its 

 first growth, b- An underground stem just 

 beginning to thicken and thus form a tuber. 



c. Tuber terminating a stem which grows 

 from the axil of a bract on the upward 

 growing stem just below the surface of the 

 ground. Roots also grow from this stem. 



d. A pair of bracts, e. A three-join ted tuber. 



plant. The smilacina rootstock produces usually but oue 



bud to succeed the old plant; 



but a single potato plant pro- 

 duces many tubers, each with 



several eyes. 



Corms are short vertical 



rootstocks similar to tubers, 



but each node produces true 



leaves which appear above 



ground, and only a single 



strong bud produces a new 



plant. The bases of the leaves 



form several thin coats. Fig. 



34 and Fig. 35 show corms which resemble bulbs and are 

 usually called solid bulbs. 



Bulbs resemble winter buds, but are 

 much larger, and instead of thin dry scales 

 the juicy thickened bases of the last sea- 

 son's leaves surround the real live bud. If 

 these bulb scales are broad, 

 so that each envelops all 

 within, a tunicated bulb is 

 formed. Narrow and very 

 thick scales make a scaly bulb. 

 Common cultivated onions 

 have tunicated bulbs. Most 



lilies have scaly bulbs. Some of our Fritil- 



larias have, besides a few large scales, numerous small 



Fig. 34. Half-solid 

 bulb of Brodisea 

 capitata with young 

 tulbs which termi- 

 nate short rootstocks. 



Fig. 35. Half- 

 solid bulb of Al- 

 lium serratum. 



