396 THE FLORA. 



b Involucre none. Anthers 4-valved. Leaves lobed. Sassafras. Sas'safras. 1 

 b Involucre 4-Ieaved. Anthers 2-valved. Shrubs. Spice-hush. Ben'zoin, 



b Involucre 4-leaved. Anthei-s 4-valved. Shrubs. S. Pond-spice. Tetranthe ra. 



SASSAEKAS. Sassafras. 

 Flowers dioecious, 6-parted, regular. Stamens 9. Trees with decidu- 

 ous leaves, expanding after the clusters of yellow flowers. 

 S. officina^le. Common S. Leaves of two forms, ovate and entire, or 3-lobed and 

 acute at base. Tree aromatic, 10-80f. high. 



Order CXIX. CUPULIFERiE. The Mastworts. 



Trees or shrills.^ with alternate, simple leaves, and deciduous stipules; 

 fioioers monoecious, the sterile in aments, which are racemed or head-like ; 

 stamens in the sterile flowers, 6 to 20, on the base of the calyx; 

 otary in the fertile flowers with several ceils and ovules, hut hecomjpg ia 

 fruit a 1-seeded nut surrounded by an involucre (cup, burr, or sac). 



Analysis of the Genera. 



§ Sterile flowers in aments, fertile flowers so-litary or 2 or 3 together 2 



§ Sterile flowers and fertile also in aments, the latter loose and large c 



2 Involucre 1-flowered, cup-like, composed of many little scales a 



2 Involucre 2 or 3-flowered, composed of few large valves b 



a Sterile aments slender, calyx 5-cleft, stamens 5 or 10. Fertile flowers, con- 

 sisting of an ovary sitting in a scaly cup, becoming, in fruit, an acorn., 1- 

 celled, 1-seeded. A noble genus of trees (rarely shrubs), always known by 

 their peculiar fruit, called acorns. The timber is of great value, especially 

 in ship-building. In the Class Book of Botany, 23 species are described. 

 (See Figs. 32-34, 2^57.) Oalc. Querctis. 1 



b Involucre of the fruit and fertile flowers a burr with 4 valves. Sterile aments 

 slender, each flower with 5-15 stamens ; 3 fertile flowers in each involucre, 

 which is beset with slender prickles. We have two species, one a tree, the 

 other a shrub. Timber excellent. The fruit is sweet and nutritious. (See 

 Fif. 277.) Chestnut. Casta ''nea, 



b Invohicre of the fruit a burr with 4 valves. Sterile aments head-like, sus- 

 pended by a slender stalk. Calyx 6-cleft. Two flowers in each burr, which 

 is covered by weak spines. Nuts sharply 3-angled. They are tall, valua- 

 ble forest-trees. -^^^^^- 1^'aocp. 



b Involucre a sac, longer than the nuts, torn at the top. Sterile flowers in a 

 slender ament. Shrubs. Usually but one flower or nut in each involucre. 



Hazel. Cor'yi»us. 



