CL. XXI.] MON03CIA MONANDRIA. 345 



20. QUE'RCUS. Barren flowers in a loose catkin. Calyx divided into 



several segments. Corolla none. Stamens eight or more. 

 Fertile flowers. Calyx double ; the outer inferior, scaly, undivided ; 

 the inner superior, with six deep segments. Corolla none. Style 

 one. Nut solitary, closely invested at its base with the hemisphe- 

 rical outer calyx. 



24. CO'RYLUS. Barren flowers in a cylindrical catkin. Calyx a three- 

 cleft scale. Corolla none. Stamens eight or more. 

 Fertile flowers. Calyx double ; the outer inferior, divided ; the in- 

 ner superior, minute. Corolla none. Styles two. Nut solitary, 

 hard, invested by the enlarged, leathery, outer calyx. 

 23. CARPl'NUS. Barren flowers in a cylindrical catkin. Calyx a 



rounded scale. Corolla none. Stamens ten or more. 

 Fertile flowers. Calyx double ; the outer inferior, of several deci- 

 duous scales; the inner superior, with three deep, egg-shaped, 

 acute, permanent segments. Corolla none. Styles two. Nut egg- 

 shaped, angular, naked. 



22. BETULA. Barren flowers in a cylindrical catkin. Calyx a ternate 

 scale. Corolla, none. Stamens ten or twelve. 



Fertile flowers in an oblong catkin. Calyx a three-lobed, three- 

 flowered scale. Corolla none. Styles two. Nut winged, deci- 

 duous. 

 18. A'RUM. Common calyx a sheath inclosing a common stalk, naked 



above. Corolla none. 

 Barren flowers. Stamens numerous, in a dense ring, surmounted by 



a ring of abortive filaments. 



Fertile flowers. Germens numerous, in a dense ring beneath the 

 stamens, sessile. Styles none. Stigmas downy. Bern/ one-celled, 

 with several seeds. 



Order VII. MONADELPHIA. Filaments united. 



25. PI'J\ T US. Barren flowers in a catkin, naked. Stamens numerous, 



on a common stalk. 



Fertile flowers in a catkin of imbricated, close, stiff, two-flowered 

 scales. Seeds two to each scale, winged. 



MONCECIA. MONANDRIA. 



1. EUPHO'RBIA. SPURGE. 



Involucre of one leaf, with four or five marginal lobes, perma- 

 nent, containing several barren flowers, and one central fertile 

 flower, all destitute of calyx and corolla. Nectaries four or five, 

 fleshy, tumid, abrupt, coloured. 



Barren flower. Filament simple, hair-like, erect. Anther of 

 two globular separate lobes. 



Fertile flower. Germen roundish, three-lohed. Styles three, 



equal, cleft, spreading, permanent. Stigmas bluntish. Capsule 



roundish, three-lobed, three-celled. Seeds one in each cell, large, 



roundish. Named after Euphorbus, physician to Juba. 420. 



2 G 



