49. Anacardiaceae 107 



1. Leaves elliptical, acuminate, serrate; calyx-lobes ciliate; nutlets 

 smooth; woods and swamps; more frequent in the northern 

 counties. Winterberry /. vcrlicillala (L.)A.Gray 



49. Anacardiaceae Lindl. — Sumac Family 



1. Rhus L. 



{Toxicodendron Mill.; Schmaltzia Desv.) 

 1. Leaves with 7-31 leaflets. 



2. Leaflets deciuTent on the rachis, which is therefore conspicu- 

 ously winged : fruit red, pubescent ; roadsides, fields, and 

 open woods, often in sandy soil, locally throughout 111., except 

 the central counties. July-Aug. Shining Sumac. Dwarf 



Sumac. [R. copallina var. latifolia Engler] R. copallina L. 



2. Leaflets not decurrent; rachis not winged. 

 3. Leaflets serrate; truit red, in terminal clusters. 



4. Twigs and leaves glabrous; along roads and fences, and in 

 open woods, common throughout 111. June-July. 

 Smooth Sumac. {R. media Greene; R. valida Greene] 



R. glabra L. 



4. Twigs and petioles villous-hirsute ; woods in the northern 

 half of 111.; occasionally introd. elsewhere. June-July. 



Staghorn Sumac. [R. hirta (L.) Sudw.] R. typhitia L. 



3. Leaflets entire or nearly so; fruit glabrous, whitish or pale 

 greenish, in axillary panicles; plants poisonous to the touch; 

 tamarack bogs and swampy ground; Coles, Cook, Kanka- 

 kee, Lake, McHenry, and Woodford counties. Jime-July. 



Poison Sumac. [R. venenata DC] R. vernix L. 



1. Leaves with 3 leaflets. 



5. Flowers in loose axillary panicles, appearing after the leaves; 

 fruit glabrous, greenish-white; plants erect, trailing, or climb- 

 ing, poisonous to the touch ; along fences and in woods, or on 

 sand dunes, common. May-July. Poison-ivy. [R. toxicoden- 

 dron sensu auth., non L.] R. radicans L. 



5. Flowers in short dense panicled spikes, catkin-like before open- 

 ing, appearing before or with the lea\es; fruit red, pubes- 

 cent; foliage not poisonous, fragrant when bruised. 

 6. Flowers nearly sessile, appearing before the leaves: leaflets 

 2-6 cm long, rhombic-obovate to ovate, acute; petioles 

 villosulous to nearly glabrous; gra\elly or rocky banks, 

 locally throughout 111., except the northern counties; more 

 frequent southward. Apr.-May. Fragrant -Sumac. [R. 

 canadensis Marsh., non Mill.: R. crenata sensu Rydb., non 

 Thunb. ; Schmaltzia jormosa Greene; S. illinoensis Greene] 



R. aromatica Ait. 



6. Flowers on pedicels 2-3 mm long, on leafy twigs; leaflets 1- 

 2.5 cm long, obtusish, crenately few-lobed or -toothed 

 above the middle; petioles puberulent or tomentulose; 



