GENERAL KEY TO THE POLYrETALOlS ORDERS. xiii 



(sometimes dimorphous and in part cleistogamous) dii-hlainyd<-ous. Ovules soli- 

 tary in the cells of the mostly :i-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 Pf^f/anum) deeply 

 pinnatifid, not pellucid-punctate (although sometimes 6Uperfi<ially resinous- 

 dotted). 



31. ZYGOPIIYLLACE.E. Flowers solitary, 4-G-merous, perfect, dichlamydeous (or 

 petals very rarely wanting), diplo (rarely triplo)-st«'monous, 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 Oralis) : calyx 

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

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



32. GERANI ACPLE. Flowers perfect, 3-6- but mostly 5-merous, regular or strongly 

 zygomorpiiic (then saccate-spurred), mostly showy. €arj:)els 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 

 RutacetB but) without solitary or geminate glands : filaments unapi)endaged 

 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 aix)car- 

 pous ovary. Fruit various, capsular, samaroid, drupaceous, or in the Auraut'u(t 

 tough-rinded and baccate. 



6. Leaves without glands in their substance. 



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

 technical characters of Rutacece but foliage devoid of glandular dots. Our sinn-ies 

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

 Arizono-Texan region. 



35. BURSERACE.E. Resiniferous trees an.l shrubs with alternate ex>tipulate 

 odd-pinnate leaves and small polyganio-<lio'eious :?-r>-merous Jlowers. Fruit a 

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

 thickish valves ; cotyledons thin and contortuplicate. Our sp«»cies (confined to 

 S. Florida and S. Arizona) with 3-celled ovary and '2 pendulous ovules in each 

 cell. 



