58 MONOCOTYLEDONS^. 



As we find the greater number of bulbous and 

 tuberous stemmed plants, to be vernal flowerers, and 

 that they chiefly rest during- the heat of summer ; 

 it may be reasonable to conclude that these protube- 

 rant appendages are a necessary provision of nature 

 to defend the vital organs against the effects of 

 insolation. 



A very conspicuous family in this group is the 

 Iridece. For splendour of colour curious forms 

 and variety of specific characters, it vies even with 

 amaryllidece. The most striking physical character of 

 the Iris genus is their tuberous stems, partly beneath 

 and partly above the surface of the ground. Vital 

 gems are seated not only at the summit but also on 

 the sides of the stem ; consequently it becomes 

 branched. The stems also exsert roots from every 

 part of their surface. 



The order Mut&cea next claims attention, not be- 

 cause it is different in its elements and organisation 

 from many of the preceding, but because it contains 

 some of the largest herbaceous plants known. So 

 magnificent, indeed, are the stem, leaves, flowers, and 

 fruit of the Plantain, that it is commonly called a 

 tree ; it is however only a gigantic herb. The roots 

 are fibrous, diverging from the compound collet, which 

 throws up a succession of young stems as the oldest 

 yield their fruit and die. The full grown stem is 

 from five to nine inches in diameter, and from ten to 

 fifteen feet high. The stem is chiefly composed of 

 the bases of the petioles : and when the fruit is ripe it 



