EXOGENOUS OR DICOTYLEDONOUS PLANTS. 



399 



773. Ord. SterculiacefE, very closely allied to the last two, and con- 

 sisting of tropical trees, possesses the same mucilaginous properties 

 (as well as oily seeds), with which hitter and astringent qualities are 

 often comhined. The seeds of Bombax, the Silk-cotton tree, are 

 enveloped in a kind of cotton, which belongs to the endocarp and 

 not to the seed ; and the hairs, being perfectly smooth and even, can- 

 not be spun. Canoes are made from the trunk of the huge Bombax 

 Ceiba, in the West Indies. To this order belongs the famous 

 Baobab, or Monkey-bread, of Senegal (Adansonia digitata), some 

 trunks of which are from sixty to eighty feet in circumference ! 

 The fruit resembles a gourd, and serves for vessels ; it contains a 

 subacid and refrigerant, somewhat astringent pulp ; the mucilagi- 

 nous young leaves are also used for food in time of scarcity ; the 

 dried leaves (Zafo) are ordinarily mixed with food, and the bark 

 furnishes a coarse thread, which is made into cordage or woven into 

 cloth. Cheirostemon platanoides is the remarkable Hand-flower 

 tree of Mexico. A plant of the family (Fremontia, Torr.) nearly 

 allied to Cheirostemon has been found in California, by Fremont. 



774. Ord. TiliaccEB {Linden Family). Trees or shrubby plants, 

 with alternate leaves, furnished with deciduous stipules, and small 



flowers. Calyx deciduous. Petals sometimes imbricated in asstiva- 



FIG. 742. Flowering branch of Tilia Americana the common American Linden ; the flower, 

 stalk cohering with the bract. 743 One of the clusters of stamens adhering to the petaloid 

 scale 744 The pistil. 745. Cross-section of the fruit, which has become one-celled by the 

 obliteration of the partitions, and one-seeded. 748 Vertical section of the seed, magnified, to 

 show the large embryo with its taper radicle and foliaccous crumpled cotyledons. (A better 

 section of the seed, cut in the direction across tile cotyledons, u shown in Fijf 699.) 747. 

 l)iagram of the flower. 



