102 Plants and their Ways in South Africa 



one whorl is usually called the calyx. If any one or more 

 whorls of the flower are wanting, the flower is incomplete. 



After a few weeks the Clematis loses its sepals, and only 

 the seed-forming portion remains. A flower exists for the 

 sake of forming seed. The ovules within the ovary cannot 

 become seeds without the pollen from the stamens; so the 

 stamens and pistils are called the essential organs. 



If the anthers are removed from any flower before they 

 shed their pollen, and the flower is then covered or removed 

 from any similar flower, the ovaries will wither away and form 

 no seed. If, after the stamens were removed, pollen were 



brought from a similar 

 flower and placed at 

 the right time on the 

 stigma, the pistil would 

 continue growing, and 

 seeds would be formed 

 as though there had 

 been no disturbance, 

 even though the petals 

 and sepals were re- 

 moved. A perfect 

 flower has both sta- 

 mens and pistils. In 

 the flowers which bear 

 the seed in the Silver 

 Tree, Indian corn, or 

 Mojitifiia stamens are wanting, while those that have stamens 

 produce no seed. Flowers in which either set of essential 

 organs is wanting are imperfect. If the pistils are wanting, 

 the flowers are staminate. If the stamens are absent, the 

 flowers are pistillate or fertile. A perfect flower is some- 

 times called bisexual or hermaphrodite. The willows and 

 arums have neither calyx nor corolla. A flower may be reduced 

 to a single stamen or a single pistil, as in some Euphorbias. 

 A complete flower has — 



(i) Calyx, made up of sepals. 

 (2) Corolla, ,, ,, petals. 



Fig. 105. — Leucospervmin clliptic2<n!. L. c. has no 

 corolla. The flower is incomplete. (From Ed- 

 monds and Marloth's "Elementary Botany for 

 South Africa.") 



