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A TEXT-BOOK OF BOTANY. 



Many of the herbs have subterranean shoots, but these are 

 generally absent from woody plants, excepting in Sambucus, 

 Ailanthus, Calycanthus, etc. The herbs may be further sub- 

 divided as annual, biennial, and perennial. 



FIG. 188. Longitudinal section through a germinating bulb of Tulipa prcecox: h. 

 the brown enveloping membrane; k, the flattened stem which forms the base of the bulb 

 and bears the bulb-scales (sh); si, the elongated part of the stem which bears the foliage- 

 leaves (1'T), and terminates in the flower; c, the ovary; p, perianth; a, anthers; 2, a lateral 

 bulb in the axil of the youngest bud-scale, which develops into the bud of next year's bulb; 

 w, the roots which arise from the fibrovascular bundles at the base of the bulb. After 

 Sachs. 



In ANNUAL herbs the individual possesses only aerial shoots 

 and the plant sets fruit the same year that the individual has de- 

 veloped from the seed. In BIENNIAL herbs the plant does not 

 produce flowers until the second season. The PERENNIAL herbs, 



