CLASS DIADELPHIA. 
171 
btyles ; the ovary is formed by the union of the caipels 
round a common axis. Among the plants which compose this 
family, are the hollyhock, mallows, and cotton {Gossypium). 
The Cameli A japonica is in this artificial class and order. 
rt. 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-cStton tree 
(BoMBAX pentandrum) is so large, and spreads its branches so widely, that twenty 
thousand persons 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 
eize 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 period of 
time for the existence of any species of organized bodies."* 
LECTUEE XXXIII. 
CLASS XVI. ^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^ hnt with fiowers papilionace- 
ous which are retained in Diadelphia though there be no ap- 
parent division in the brotherhood ; and that though the flower 
be papilionaceous^ if it have ten separate stamens it is placed 
in the tenth class. Linngsus, in reference to the form of the 
flowers^ arranged this tribe under a natural order Papilio' 
nacem ; — Jussieu regarding the fruity called the same Legmnv 
nosce. 
Fig. 148 represents the sweet-pea {Lathyrus odo- 
ratus) ; at a is the five-toothed calyx ; at b the 
upper petal called the vexillum or banner ; at c the 
wiuffs or two side petals ; at d is the keel formed of 
two petals united by their edges ; at c are the 
ten stamens, nine united, and one separate ; at f is 
the pistil, the base of which in process of time be- 
comes the pod or legume. 
250. The flowers of the leguminous 
plants 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 la, 
• B. S. Barton. 
a. Adansonia. — 249. Class Diadelphia — What circumstances to be observed with respect to tbis 
«.la88 ?~Natural order Papilionacese—Legurninosa— Describe Fig. 148. 
