DEVELOPMENT OF PLANTS 431 



later they elongate and bear some of the spores to the stigma. 

 The reverse position of the sporophylls also occurs, but the out- 

 ward opening of the anthers keeps the microspores from dropping 

 by chance on the stigma until the stigma is finally lifted up to 

 the anther by the elongation of the style, where it is sure to be 

 dusted with spores, as the anthers open wider and wider. Certain 

 species are characterized by an extraordinary twisting of the 

 filaments, so that for a time the anther is turned away and bent 

 over towards the perianth so as to be in line w4th the nectar glands, 

 and later, at the close of the flowering period, a reversal of this 

 bending brings the anther in contact with the stigma. These 

 illustrations are sufficient to show that the flowers have many 

 arrangements and exact movements that result in crossing, or, 

 if this fails, in autogamy. You would naturally expect that 

 specialized flowers like the mustards would show higher types of 

 coloration. This is indeed the case in some forms where pink and 

 purple colors appear, but in the majority of the species the un- 

 favorable situations in which they grow have resulted in a reduc- 

 tion in the size of the flowers and also in a decline in color to 

 white and pale yellow. It is noteworthy that the flowers of the 

 radish when cultivated on barren soil develop white, but upon 

 rich soil, pink. These minute flowers have a decided advantage 

 in being grouped in compact inflorescences, a device that you 

 will see copied again and again in the higher orders because it 

 ensures crossing and makes them conspicuous. It should be 

 stated that several of these plants get along very well without 

 crossing. 



Many products of great commercial value are derived from 

 various members of this order. Opium, from which morphine 

 and other alkaloids are obtained, is the dried latex obtained from 

 the incisions of the unripe capsules of the Turkish poppy. The 

 majority of these plants contain acrid or peppery juices that 

 render certain parts of the plant or their seeds of value as spices, 

 oils, foods, etc. Many of them are biennial, forming a close 

 rosette of leaves the first year and flowers and fruit the second. 

 By cultivation an abnormal development of one part or another 

 of the plant has been induced. This feature is well illustrated 



