Classification of Plants 



267 



constructed for another purpose — that of distributing the seed. 

 The calyx is known as the pappus. After flowering, it may 

 enlarge into a parachute for carrying the seeds in the wind, or 

 it is developed into bristles, which seize hold of animals and 

 so obtain a free ride. The corolla is gamopetalous. All the 

 flowers may be tubular and regular or all may be strap-shaped, 

 or the central disc flowers may be tubular and surrounded by 

 the strap-shaped (ligulate, " little tongue ") ray flowers. The 



Fig. 269. — Cypia zeyheriana. 



ray flowers are usually developed at the expense ot the stamens, 

 and contain only pistils. Stamens 5, alternating with the 

 petals, cohering by their anthers (syngenesious), as in Lobelia, 

 forming a tube around the style. Ovary inferior, of two 

 carpels with a simple style forking into two stigmas. The 

 one-celled ovary contains one ovule^ growing from the base of 

 the ovary. The fruit is an achene. 



Since the flowers are massed together, they may be very small, and yet 

 form an attractive cluster for insects, especially when there are ray flowers. 

 One insect may visit a great many flowers in a short time. The slender 

 tube and united stamens protect the honey and pollen ; if cross fertilization 

 fails, the divided stigmas may turn back and pollinate themselves. The 



