The Angiosperms or Flowering Plants 523 



Distinguishing features of the dicotyledons. The embryo has 

 two cotyledons, except in certain parasites and saprophytes. 

 The stems are either herbaceous or woody, with open vascular 

 bundles arranged in a circle, and usually with a cambium inter- 

 secting the bundles between xylem and phloem tissues. The 

 stems of most dicots are profusely branched. The primary root 

 is retained until maturity, and not infrequently develops into a 

 long tap root. The leaves are usually net-veined, simple or com- 

 pound, entire or variously lobed and divided. The flowers are 

 usually made up of five cycles of floral parts : the sepals, petals, 

 two whorls of stamens, and the carpels. The number of members 

 in each cycle varies from two to six, but is usually five or four. 

 In some of the simplest flowers the corolla is wanting, and in 

 others there is but a single whorl of stamens or pistils. In some 

 families the number of stamens and pistils is very large. 



Distinguishing features of the monocotyledons. The mono- 

 cots are herbs and woody plants, with closed and scattered bun- 

 dles. The embryo has usually only one cotyledon, sometimes 

 one large one and a very small one. A cambium is usually 

 absent, but when secondary cambiums are present they arise 

 outside the vascular bundles. The stems of monocots are not 

 as highly branched as those of the dicots. The primary root is 

 usually short-lived, and is replaced by adventitious roots, which 

 are in turn succeeded by new adventitious roots that develop 

 from points higher and higher up the stem. 



The leaves are devoid of stipules and commonly lack a petiole, 

 though they frequently have a sheathing leaf base. The flowers 

 consist of five cycles of floral organs, as in the dicots, but the 

 second whorl of stamens is not infrequently wanting. The 

 number of members in each cycle is usually three, but in the 

 grasses this may be reduced to two. 



REFERENCE 



Coulter, J. M., and Chamberlain, C. J. Morphology of the Angiosperms. 

 D. Appleton & Co., New York ; 1903. 



