THE BULB BOOK 



BULBS, CORMS, TUBERS, RHIZOMES 



OUTSIDE the ranks of botanists and skilled gardeners, much 

 uncertainty and no little confusion prevail as to what constitutes 

 a bulb, a corm, a tuber, or a rhizome. It may be well therefore to 

 say a few words about each, with a view to making things plainer in 

 regard to these matters. 



BULBS. A bulb is a special kind of bud bearing a number of 

 thickened fleshy or scaly learns closely packed together and seated 

 upon a flattened compressed or disc-like woody stem, from the under- 

 surface and edges of which roots are produced during growth. 

 Examples of true bulbs that will fit this description may be seen in the 

 Onion, Tulip, Hyacinth, Daffodil, Snowdrop, Squill, the Snowflakes, 

 and many others. In most cases the fleshy leaves are rolled round 

 each other ; the bulbs are then said to be tunicated. In the case of 

 the Liliums, however, in which the thickened leaves are overlapping 

 each other in a spiral fashion round the main axis, the bulbs are said 

 to be scaly or imbricated. The drawings will give a good idea as to 

 the difference between " tunicated " and " imbricated " or " scaly 

 bulbs." Figs. 1 to 3 represent the former; Fig. 4 represents the 

 latter. 



CORMS. These are often described as " solid " bulbs, owing to the 

 fact that in many cases they bear a superficial resemblance to bulbs 

 proper. In many cases, however (e.g., the tuberous Begonia and the 

 Cyclamen), the term "corm" is very loosely and erroneously used 

 when speaking of the tubers of these plants. The one obvious 

 difference between a true bulb and a true corm is, that the latter is 

 quite solid, and has neither tunicated, imbricated, nor scaly leaves 

 seated on a compressed disc-like stem, a section of which is shown 

 in Fig. 1. The corm is a rounded or flattish stem on which traces of 

 the leaf -stalks or bases may be seen. Another great difference 



1 A 



