68 



DICOTYLEDONS 



..S. 



--C. 



Fig. 70. — Fruit 



(aclienium) of the 



Sunflower (opened) 



S. Seed. 



C. Fruit case. 



The riower contains honey in great quantities which is secreted 

 at the base of the style and often tills the whole globular part 

 of the tubular florets (tig. 69, H.) But a single floret would be 

 so inconspicuous that it woukl hardly be noticed by the guests 

 which are so eagerly expected. We see, now, 

 how advantageous it is for the plant that its 

 small inconspicuous florets should be placed to- 

 gether in large number forming heads of flowers 

 (compare Mango, page 28). The ettect of their 

 being clustered is enhanced by the presence of 

 the ligulate (strap-or tongue-shaped) florets on 

 the margin. We seek in vain for styles and 

 stamens in these flowers: they are sterile. But 

 by attracting tlie useful insects they fiilfll the 

 purpose for which they Avere created. Each 

 ligulate floret has Ave nerves showing that it is 

 composed, like the tubular florets, of Ave connate 

 petals, forming a short tube at their base. 

 4. The Fruit, when ripe, does not open, bnt remains shut. 

 It is called an achenium. Each fruit contains one seed under 

 its hard cover. In flg. 70 tlie front half of tlie fruit case is 

 removed showing liow the seed in tlie case is connected with the 

 base of the fruit by a small cord (called funicle). When the wind 

 shakes the tall plants one against the other, the achenia fall and 

 from the eflect of the blow are scattered around {cf. Poppy, page 9). 

 The seed contains a fatty oil in its cotyledons which serves 

 as food for the young plant destined to grow out of it. 



The Ghat Edelweiss (Anaphalis oljlonga). 



This plant may be taken as a type of the flora of high moun- 

 tains. It is a small weed, branched from the root, all covered 

 with white woolly hairs (tomentum), an ally of the l)eautiful Alpine 

 " Edelweiss". 



1. To understand its structure it is nci-essary to remember 

 the conditions of the Alpine climate. I'he ruling influence of 

 highlands is the diminished atmospheric pressure which brings 

 in its train a number of secondary climatic ett'ects. 



