n6 THE BOOK OF NATURE STUDY 



The multiplication of plants by means of seeds is a sexual 

 method of reproduction, that is to say, it involves the union of 

 two cells produced, so far as flowering plants are concerned, 

 in the stamen, or male portion of a flower, and the carpel, or 

 female portion of the flower, respectively. The other method 

 of multiplication of plants is by vegetative reproduction, which 

 involves the separation from the parent plant of a portion of 

 its leaf-stem or root, such portion developing roots and thus 

 becoming a new plant. The act of separation may be the 

 result of the natural growth of the plant, or it may be effected 

 artificially. 



THE CORM. This is really a short underground thickened stem 

 coated with membranous scales. To understand the method of 

 reproduction, dig up Crocuses (Crocus verni) in the spring, after 

 the flowers have died down, and note : (a) at the base, the 

 adventitious roots, with possibly the remnants of the corm of 

 the preceding year; (b) above these, the corm of the year, 

 which is now shrivelled, owing to its reserve substances having 

 been partly used up in producing the leaves and flowers which 

 have just withered ; (c) the new corm, which will be mature by 

 the end of the summer, and which is being stored with food 

 material for the growth of the leaves and flowers of the succeeding 

 season. With the corm of the Garden Crocus compare the corm 

 of the Gladiolus. 



THE TUBER. This is also a stem, usually underground, and 

 possessing small membranous scale-leaves from whose axils 

 buds arise. Dig up a young potato plant in the early summer, 

 and note that the tubers are swollen portions of underground 

 stems. Select a very small tuber, and with the aid of a magnifying 

 glass make out the scale-leaves near the " eyes " of the tuber. 



THE BULB. A bulb consists of a relatively short stem which 

 is enveloped by a number of fleshy scale-leaves. The essential 

 difference between a bulb and a corm is that the reserve material 

 is in the former stored in the scale-leaves, and in the latter in 

 the stem. Dig up a growing Onion, Hyacinth, or Tulip, and 



