180 BOTANY. [chap. v. 



with this idea is certainly the most conspicuous of 

 features characteristic of Angiosperms. 



Angiosperms in turn are divided into the two follow- 

 ing primary sections, depending on minor modifications 

 of the important structural characters of the group. 



I. Monoeotyledones . 



Kbro-vascular bundles closed, scattered. Embryo with one coty- 

 ledon. Whorls of the flower in threes or multiples of three. 



Other features characteristic of the present section 

 are the arrangement of the veins of the leaf, which are 

 usually described as parallel in arrangement, the complex 

 network, seen best in a "skeleton leaf" and charac- 

 teristic of the following section, being usually absent. 

 The general build of the leaf is also comparatively simple, 

 being usually long and narrow, as illustrated by grasses 

 and snowdrops, the margin as a rule is entire, the leaf is 

 not articulated to the stem, but after having performed 

 its functions remains hanging to the stem until it decays. 

 There is also an absence of so-called sensibility, or re- 

 sponsions in the way of movements to external stimuli. 

 The spathe, as already explained, is a form of floral 

 protection met with only in the present group. A 

 common mode of vegetative reproduction is by the 

 formation of bulbs, which generally consist of a number 

 of closely-packed modified leaves that are usually fleshy, 

 owing to the presence of store food materials, starch, etc. 

 The two outermost floral whorls, calyx and corolla, are 

 usually coloured, and together are often called the 

 Perianth. 



The following are amongst the most characteristic 

 orders of Monocotyledons. Palmce, palms ; Liliacece, 



