26 



FLOWERS 



of hair-like structures called pappus, as shown in Figure 24- In 

 some, as the Dandelion illustrates, the pappus remains after the 

 seed is mature, forming a parachute-like arrangement which 

 assists in floating the seed about. In some of the Composites, 

 the calyx consists of a few teeth, which in the Spanish Needles 

 and Beggar's Tick, become spiny, and 

 thcreb}^ assist in seed distribution by 

 catching onto passing objects. 



Orchid Flowers. — It is among 

 Orchid flowers, many of which are 

 spectacular, that the most notable 

 irregularities occur. Besides the dis- 

 tinguishing feature of having the 

 stamens and pistil joined into one 

 body, known as the column, Orchid 

 flowers often have pronounced varia- 

 tions in the shape and size of petals. 

 In some, as in the Lady's-slipper, one 

 of the petals is developed into a great 

 sac or " slipper," while the others 

 have no extraordinary features. These 

 peculiarities in flower structure, which 

 are apparently adjustments for insect 

 pollination, sometimes so closely con- 

 form to the shape and habit of cer- 

 spadix which is enclosed in the tain insects that only one or a few 

 large leaf-hke bract or spathc. kinds of insects can pollinate a flower. 

 Reduced about one-half. g^^^ highly modified flowers contrast 



strikingly with the simple, inconspicuous flowers of such plants 

 as the Jack-in-the-pulpit or Indian Turnip and Skunk Cabbage, 

 in which a perianth is either lacking or inconspicuous and the 

 flowers are crowded on a fleshy spike, known as a spadix, which 

 is enclosed in or attended by a leaf, called spathe. The spathe, 

 by becoming colored, often aids like a corolla in attracting 

 insects. (Figs. 25 and 26.) 



Fig. 26. — The inconspicu- 

 ous flowers of the Indian 

 Turnip (Arisoema Iriphyllum) . 

 The flowers shown are pistil- 

 late and are clustered at the 

 base of the fleshy 



Arrangement of Flowers or Inflorescence 



The arrangement of flowers on the stem is one of the floral 

 characters much used in the classification of the Flowering Plants. 

 In the arrangement of flowers, a number of things are considered. 



