CLASS DIADELPHIA. 171 



styles ; the ovary is formed by the union of the carpels 

 round a common axis. Among the plants which compose this 

 family, are the hollyhock, mallows, and cotton {Gossypium). 

 The (jAiiiELTA jaj}07iica is in this artiticial class and order. 



a. The plants of the class Monodelphia vary in size, from the low mallows to 

 some of the largest trees that have yet been discovered ; " the Silk-cotton tree 

 (BoMBAX pentandrum) is so large, and spreads its branches so widely, that twenty 

 thousand jDcrsons might stand under them : this tree is a native of Africa and 

 America. The Adansonia, a native of Senegal in Africa, is said to grow to the 

 eizc of seventy feet in circumference ; this tree also attains great age. In 1749, 

 the learned Adanson saw two of these trees in the neighborhood of Gorrea, upon 

 one of which was inscribed the date of the fourteenth, and upon the other that of 

 the fifteenth century ! yet there were good reasons to suppose that the trees were 

 not young when the dates were cut. It may be conjectured that they have some- 

 times attained to the age of eight or nine hundred years ! an immense periofl of 

 time for the existence of any species of organized bodies.""^ 



LECTUKE XXXIII. 



CLASS XYI, DIADELPHIA, TWO BROTHERHOODS. 



249. This is the class of two brotherhoods, the stamens being 

 united by their filaments into two sets. The flowers are Pa- 

 'pilionaceous. It should be observed that there are some plants 

 with filaments united in one set^ but with flowers papilionace- 

 ous which are retained in JDiadelphia though there be no ap- 

 j)arent division in the brotherhood ; and that though the flower 

 be p>apil{onaceous^ if it have ten separate stamens it is placed 

 in the tenth class. Limigeus, in reference to the form of the 

 flowers^ arranged this tribe under a natural order Papilio' 

 nacem ; — Jussieu regarding the fruity called the same Legumi- 

 nosce. 



Fig. 148 rej^resents the sweet-pea {Lathyrus odo- 

 ratus) ; at a is the five-toothed calyx ; at 6 the 

 upper petal called the vexillum or banner ; at c the 

 wings or two side petals ; at d is the keel formed of 

 two petals united by their edges ; at c are the 

 ten stamens, nirie united, and one separate ; at / is 

 the pistil, the base of which in process of time be- 

 comes the pod or legume. 



250. The flowers of the leguminous 

 phmts are so peculiar in appearance 

 that they are easily recognized. They 

 are called by botanists irregular. The 

 rose, pink, and bell-flower are regular in their form ; that is, 



• B. S. Barton. 



a. Adansonia.— 249. Class Diailclphia— What circumstances to be observed with respect to this 

 class?— Natural order Papilionaces—LeguminosiE— Describe Fig. 148. 



