146 



PAETICULAK FORMS OF FLOWERS 



mens? Describe a mallow flower. Orchid flower. Spathaceous flower. 

 Compositous flower. What do you understand by the terms hypo- 

 gynous, perigynous, epigynous? How do 

 flowers become double? What is meant 

 by doubling in compositous flowers? In 

 snowball and hydrangea? 



NOTE. The flowers of grasses are 

 too difficult for the beginner, but if the 

 pupil wishes to understand them he may 

 begin with wheat or rye. The "head" or 

 spike of wheat is made up of flowers 

 and brac.ts. The flowers are in little 

 clusters,or spikelets ( often called " breasts" 

 by farmers) . One of the spikelets is 

 shown at 6, in Fig. 238. Each spikelet 

 contains from 1-4 flowers or florets. The 

 structure .of the flower is similar to that 

 of -rye-(Fig. 239) and other grasses. The 

 pistil has 2 feathery pro- 

 truded . stigmas (wind- 

 pollinated) shown at a, 

 Fig. 239. There are 3 

 stamens, 6, &, &. There 

 are minute scales in the 

 base of the flower (not 

 shown in the cut) which 

 probably represent true 

 floral envelopes. These 

 are lodicules. The larger 



238. Spikes and flowers of wheat. ^5,^0 r /7 are bracts 

 a. beardless wheat ; d, bearded P artS > C > a > c 

 wheat; 6, spikelet in bloom; c, The larger one, (?, is the 

 grain; e, single spikelet on a ma- , , ,, 



turehead. The beards in d are Howenng glume, and the 

 awns on the flowering glumes. smaller) Cj i s a pa let. 



The entire spikelet is also subtended by two bracts 



or glumes ; these are the two lowermost parts in &, Fig. 



238. The glumes of the spikelet, and flowering glumes 23 ^ Sg m e a r . &) f; 



and palets of the flowers, constitute the chaff when 



wheat is threshed. 



ing glume. 



