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A TEXTBOOK OF THEORETICAL BOTANY 



between the colour of the butterfly and the colour of the flower it normally 

 visits. Bates observed this over and over again in the Amazon jungle and 

 the same is true of a British species, the Brimstone butterfly, which is one 

 of the visitors of Primula acaiiUs, whose flowers have precisely the same 

 colour. 



Another example of a butterfly flower is Phlox paniculata, a plant 

 commonly cultivated in gardens (Fig. 1243). The flowers are produced in 

 large panicles and are very conspicuous. Each flower has a tubular calyx 



Fig. 1243. — Phlox paniculata. A, Inflorescence. B, Vertical section 

 of flower in early stage with anthers discharging pollen at the 

 mouth of the floral tube. C, Later stage after the style has 

 elongated to display the stigmas. 



made up of five fused sepals, enclosing a long corolla which is formed by 

 the fusion of five petals into a tube about 20 mm. long. The distal 

 limbs of the petals form a wide expanded surface on which the insect 

 can settle. The five stamens are epipetalous, with short filaments, and alter- 

 nate with the petals. The anthers block the entrance to the tube and open 

 by longitudinal slits. The ovary lies at the bottom of the corolla tube and 

 bears a long slender style. Nectar is secreted at the base of the ovary and is 

 stored in the corolla tube. The flowers are protandrous and the anthers 

 ripen almost as soon as the flowers open. A butterfly visiting the flower 



