112 



BRITISH PLANTS 



with membranous scales ; in bulbs the food is in the leaves, 

 which are thick and fleshy, the stem being reduced to a 

 flattened disc, bearing roots (see p. 156). 



Classification of Plants according to their Frequency 

 of Seeding. 



This is a more scientific method than by longevity, 

 which is governed by the seasons. We have already 

 pointed out that there is no strict line of division between 



FIG. 31. SWEDE, SHOWING TUBER- 

 OUS HYPOCOTYL. (REDUCED.) 



a, "collar." 



FIG. 32. KOHLRABI, SHOWING 

 TUBEROUS STEM BEARING LEAF- 

 SCARS (a). (REDUCED.) 



annuals and biennials, or between biennials and peren- 

 nials, and the estimation of age by the seasons fails alto- 

 gether in the case of plants which live in those parts of 

 the Tropics where there is no climatic interruption in the 

 development of the vegetation. 



According to the frequency of seeding, plants are 

 divisible into two groups : 



1. Monocarpic Plants (Gr. monos, once ; carpos, fruit), 

 which produce seed once and then die, and 



2. Polycarpic Plants (Gr. poly-, many), which fruit more 

 than once in their lifetime. 



