444 A^'ACAEDIACE.E. 



THE WAFEE-ASKES. Genus PTELEA L. 



Small trer-s or shrubs wirliout inirkles and witli I utter bark. Five or six species are 

 known, all uati\"es ot' the Unilei.l »States and ^lexict'. one only hi-'ing arborescent aud that 

 widely distributed tlirnui;linut central and eastern T'nited States. 



Lrnrrs usually 3-foliate, long petiolate and without stipuh-'s: leaflets conduplicate in the 

 bud. ovate or oblong, entire or serrate, pellucid-puuctate. Floir* rs greenish-white, polyga-nous. 

 iu compound terminal cj'mes : calyx -with sejjals 4-.~ or wanting; iietals 4-r». inibricated; 

 stamens of same number and altcrmile with them with subulati-' filaments, pilo-;*' at Ivs" 

 and shorter in the pistillate flowers : pistil superior. sti]iitate. with •■om pressed, li-.'l-cidh-'d 

 ovary, short .style and 2-o-lobed sticrma. Fruit an indehiseent 2-."^.-eelU-d samara, surrnimded 

 by a broad reticulate wing (or rarely wingless i : seed ])oiiited at aj^ex. ruumh'd at I'a-*' and 

 with coriaceous testa. 



The name is the ancient Greek name of the Elm. given to this genus on account of a 

 resemblance in the fruit. 



For :^ii'Cifs see pp. 30'>—oOJ. 



aUASSIA FAMILY. ST^rARl'BACE.E DC. 



Trees, shrubs and a few herlis with generally bitter milky juice and coufined mr.rtly to 



tropical regions. About one hundred) forty-five species, grouped in twenty-eisrht geuera. are 



known. Of these one arborescent genus ( simaniha ) is indigenous to the Ignited States in 



subtro]iicaI Florida. Another { AihiutJius) is extensively naturalized throughout eastern 



United States and Canada. 



Lcdvffi generally alternate and pinnate, not glandular-punctate, without stipules. 

 Floirrr.^ mostly in axillary racemes or panicles and dio'^cious ar polygamous, regular: calyx 

 3-5-lobed or parted, imbricated in the bud: petals ?^-~i (rarely wanting;!, hyposrenous : disk 

 annular or elongated; stamens as many as the petals or twice as many, with distinct Hlnmenis 

 each with a scale or hairs at base aud inserted under the disk: anthi-rs 2-ce]|ed introrse ; 

 pistils composed of 2-") united carpels each of a single cell and containing a single anatropous 

 ovule; style l-.". Fruit a drupe or samara. 



THE AIIANTHUS. Gexus AILAXTHUS Desf. 



Large handsome trees with pale bark and of two or three speeies, natives of riiina. th'^ 

 East Indies and Australia and represeulcd in thi:- United States by a single naturalized siiecies. 



Lrnvrs: sim]ile. altrenate. d.'i.'iduDUs. odd-pinnati\ with numia-ous si">mewhat obliinie snb- 

 entire leaflets. Floircrs small, in large terminal jianicles : ealyx with .") short lobes: petals .'>. 

 valvate. spreading : disk homisidiei-ir. K i-hibcd : stamens Hi ( only 2 or :^ in the pisrillate 

 flowers): ovary deeply 2-ri-lobiMl : styh's 2-.". united. Fruit sameras usually '2-'^ together, 

 linear-oblong, with membranous \-ciny winu' aud cell ci>ntaininL: a solitary compressed seed 

 at about its cpnter. 



The name is from the native ^Malla^a name of the ti'ee — AiJaiito, meaning Tree of Hcarcn. 



For species see pp. 3'J.2-303. 



SUMACH PAMILY. .VXACARDL-VCE.E Lixol. 



Trees and shrubs with resinous or milky juice, of about fifty genera and four hundreil 



species mainly of warm or trojiical res'ious. Three fjenera are ri'presented iu the trees of the 



United States. 



Lrnrrs mostly alttu'nate and \^"irhout stiimhs ; branchh't^ te'rcti"- aud wiili ]ari;<' luth. 

 Floirns small. ri'CiuIar. pol\";.'amous, did'cious or jterfeet : eal\"x lobes mostly ~) : ]>etals of same 

 number and imhrieated in the Inid or none : stamens as luauv" as the peials or twice as man,\" 

 (rarely fewer) and inserted with them <ut the edge of an annular liypogenous disk: filaments 

 filiform aud anthers oblong", introrse. l_'-celled. longitnilimili,\" dehis<"'eut : ti\-ary usuall\' 1-eelled 

 and ccintaiuiug a sulitary auatrn]ious o\uh' suspioided liy a slcmh'r funich' rising from tln' 

 base of the o\';)ry ; stylrs l-T.. stigmas ternunal. Fruit generally a small dru]ie : seed with 

 m<-mbrMui.tus or <a'ustareous roat : ruivh'dous Ih-shy and <oulaiuiug little iU- no albumen. 



KEY TO TRK (JKXF.UA. 



Styles lateral: fruit comprc'ssed with many aluu-tive ]ilumose peilicels : leaves simple. 



Cotinus. 

 Styles terminal: fruit synimetrical : leaves compound (simple in some western species'). 



Rhus. 



