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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. i88. Longitudinal section through a germinating bulb of Tulipa pracox: 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 (I'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, 



