GENERAL KEY TO THE POLYPETALOUS ORDERS. xiii 



(sometimes dimorphous and in part cleistogamous) dichlamydeous. Ovules soli- 

 tary in the cells of the mostly 3-locular ovary. Seeds exalbuminous with mostly 

 curved or coiled embryo. 



= = = Herbaceous or woody : calyx eglandular : filaments commonly 

 squamiferous : leaves pinnate or (l-)2-foliolate or (in Peganum) deeply 

 pinuatifid, not pellucid-puactate (although sometimes superficially resinous- 

 dotted). 



31. ZYGOPHYLLACE^. Flowers solitary, 4-6-merous, perfect, dichlamydeous (or 

 petals very rarely wanting), diplo (rarely triplo)-stemonous, borne on peduncles 

 which often spring from the axils of the stipules. Ovules 1 to several in the cells 

 of the 4-10-locular ovary. Fruit capsular or splitting into indehiscent cocci which 

 may or may not leave a persistent styliferous axis. Embryo large, straight, or 

 nearly so ; albumen mostly scanty and tough. 



= = = == Herbs (a little suffrutescent in some species of Oxalis) : calyx 

 eglandular (sepals often with colored callosities in Oxalis) : leaves palmately 

 or piunately lobed or divided, rarely Qnly crenate, not pellucid-punctate. 



32. GERANIACE^. Flowers perfect, 3-6- but mostly 5-merous, regular or strongly 

 zygomorphic (then saccate-spurred), mostly showy. Carpels and glands of the re- 

 ceptacle as many and stamens mostly twice as many as the sepals. Fruit usually 

 an elongated beaked capsule with elastic dehiscence or with indehiscent carpels at 

 maturity usually separating from the axis and hygroscopically coiling ; seeds ex- 

 albuminous except in Oxalis (where provided with horny albumen and special 

 arilliform elastically dehiscent integument). 



= = = = = Trees, shrubs, or (in Thamnosma and some foreign genera) 

 herbs : leaves mostly alternate and often compound : calyx (punctate in 

 Rutaceae but) without solitary or geminate glands : filaments unappendaged 

 or nearly so. 



a. Leaves dotted or punctate with mostly pellucid glands imbedded in their 

 substance. 



33. RUTACE^. Leaves exstipulate (or with stipular spines), commonly aromatic 

 or graveolent. Flowers 4-5-merous, in ours regular, symmetrical but often diplo- 

 stemonous. Disk present and usually conspicuous. Ovules 2 or more in each cell 

 of a 4:-5-locular often (especially in foreign genera) deeply parted or almost apocar- 

 pous ovary. Fruit various, capsular, samaroid, drupaceous, or in the Aurantiece 

 tough-rinded and baccate. 



b. Leaves without glands in their substance. 



34. SIMARUBACE^. Bitter-barked trees and shrubs (sometimes thorny) with 

 technical characters of Rutacece but foliage devoid of glandular dots. Our species 

 (except the cultivated and introduced Ailanihus) confined to Florida and the 

 Arizono-Texan region. 



35. BURSERACEiE. Resiniferous trees and shrubs with alternate exstipulate 

 odd-pinnate leaves and small polygamo-dioecious 3-5-merous flowers. Fruit a 

 drupe, commonly with fleshy or leathery epicarp at length deciduous as 2 or 3 

 thickish valves ; cotyledons thin and contortuplicate. Our species (confined to 

 S. Florida and S. Arizona) with 3-celled ovary and 2 pendulous o^^iles in each 

 cell. 



