Trees of the Xoktiiek.n Uniteij States 41 



2!'. Styles or stij^mas ."? or 4; pcriy:3-noii> stamens 4-o, 

 alternate with the sepals; ovulary 2-">-loenlar. ovules 

 solitary in eaeh cavity. Rham naceae. 



;i. Rhamnus. (.'34). 

 ■_'!». Styles or stigmas 2; leaves 2-ranked; ovularN- 1-2- 

 ovuled; stipules fugaceous. Ui.maceae. 

 a. Flowers in clusters on twigs of the previous sea- 

 son, pith not diaphragmed. b. 



a. Flowers on elongated twigs of the season; pith 



interruptedly diaphragmed. Celtis. (.",()). 

 1). Mowers expanding before the leaves; bark in 

 rough ridges. Ulmus. (48). 



b. Flowers expanding with the leaves; bark of trunk 



scaling off like in the Sycamore. Planera. (49). 

 2!>. Style and stigma 1. "^O. 



-■^o. Calyx 6-parted; stamens and staminodes about 12, in 

 4 series; bark spicy-aromatic. Lauraceae. 

 a. Flowers bisporangiate. panicled; leaves ever- 

 green. Persea. (15). 

 a. Flowers monosporangiatc. racemose or umbellate; 

 leaves deciduous, some of them lobed. Sassa- 

 fras. ( K) ) . 



• i". CaU'x -l-parted; stamens l'> or fewer; bark not aro- 



matic. Fab.vceae. ( Cassi.ktae). 

 See Fj above. 

 ■>". Calyx 'Vparted; stamens 5-15; flowers epigynous; jjith 

 solid hut diaphragmed. Cornaceae. 



a. Nyssa. (81 ). 



• U. 'I'wig.s with comi)lete stipular ring>; base of petiole 



covering the axillary bud; tlowers monecious, in 

 dense heads. Pl.\tan.u eae. 



a. Platanus. (17) 



31. Twigs without stipular rings. 32. 



32. Axillary buds superposed; staminatc flowers in flexible 



catkins ; leaves piimately compound. 



JlCIANI .\iK..\E. 



a. Pith .■>oIid. Hicoria. (HI ). 



a. I'ith diaphragmed, with cavities. Juglans. (t!2). 



