DEVELOPMENT OF PLANTS 427 



bine. The remarkable brilliant yellow of the flowers, as seen in 

 the buttercup and marsh marigold, etc., has been regarded as the 

 primitive coloration of the perianth, and it is to be noted that 

 the flowers showing reversion to this color assume a duller 

 yellow. This order furnishes a great variety of showy orna- 

 mental plants, but none with fragrant flowers. Many contain 

 acrid juices and poisonous alkaloids, some of which are of medic- 

 inal value, as aconite, hydrastin, helleborine, etc. Others are of 

 value for the volatile oils, as sassafras, cinnamon, camphor, nut- 

 meg, etc. The simple structure of the more characteristic flowers 

 indicates that this order is a very ancient one and the pronounced 

 tendenc}^ to vary would suggest that possibly many of the higher 

 orders of the Choripetalae have been derived from this group. 

 The origin of the monocotyledons from this order has also been 

 suggested, owing to the structural features of the embryo and 

 vascular bundles of certain groups. 



143. Papaverales, the Poppy Order. — This group includes two 

 very well known families: (i) The poppies, with such familiar 

 plants as the poppy (Papaver), sea poppy {Glaiicium) , celandine 

 (Chelidonium), soldier's cap (Biculla), fumitory (Adlumia), 

 corydalis (Capnoides) (Fig. 308). (2) The mustards, includ- 

 ing the peppergrass (Lepidium), hedge mustard (Sisymbrium), 

 white and black mustard {Sinapis and Brassica), yellow rocket 

 (Barbarea), cress {Roripa), toothwort (Dentaria), shepherd's 

 purse (Bursa), whitlow grass (Draba), rock cress (Arabis) 

 (Fig. 309). The families of the caper and mignonette are also 

 included in the order. These plants are closely related to the 

 Ranales, as is indicated by their simple and showy flowers, the 

 various organs usually being in multiples of two and quite dis- 

 tinct (flowers hypogynous) save in the case of the carpels. These 

 organs are united as in the water lilies and more commonly 

 reduced to two, thus forming a sharp contrast with the preceding 

 order. Note also that there is a sharp distinction between calyx 

 and corolla. 



(a) The Poppy Family, Papaveraceae. — The Bloodroot, San- 

 guinaria, is typical of the simpler members of this family (Fig. 

 308). These plants form colonies in rather open, rich woods 



