232 WALNUT FAMILY 



The plant is very poisonous to the touch and causes serious inflamma- 

 tion of the skin. The irritation is caused by a non-volatile oil secreted 

 by the leaves and bark and found in all parts of the plant. The effect of 

 the oil can be neutralized by applications of sugar of lead dissolved in 

 alcohol. Blossoms in May and June, fruit ripe in autumn. 



Rhus toxicodendron var. radicans (Linne) T o r r e y 



Distinguished from the preceding by the climbing habit, sometimes 

 ascending high into trees by means of roots that attach themselves to the 

 bark. The stem sometimes attains a diameter of 3-6 cm. 



In woods, thickets and along roadsides, in the southeastern part of 

 the state. 



Juglandaceae Walnut Family 



Trees with alternate, pinnately-compound leaves, stipules lacking ; 

 flowers monoecious, the staminate in catkins, the pistillate solitary, or 2-3 

 together in a cluster or spike, the staminate flowers consisting of 3-many 

 stamens and an irregular perianth, adnate to the bract, pistillate flower 

 with a 3-5 lobed regular perianth, adherent to the ovary, pistil consisting 

 of 2 carpels, ovule 1, basal, styles 2; fruit a kind of drupe with dehiscent 

 or indehiscent exocarp inclosing the bony endocarp (nut shell), nut in- 

 completely 2-4 celled, 1 seed, 2-4 lobed, cotyledons very much corrugated. 



KEY TO THE GENERA 



1. Husk indehiscent, nut rugose, pith of twigs chambered Juglans 



2. Husk splitting into segments, nut smooth or angled, pith not cham- 



bered ' Carya 



Juglans Linne 1753 

 (L. Jovis glans, nut of Jupiter) 



Trees with spreading branches, bark fragrant, buds superposed, twigs 

 with dark, chambered pith, leaves compound, odd-pinnate; staminate flow- 

 ers in drooping, cylindrical catkins, borne on the twigs of the previous 

 year, stamens 12-40, subtended by a bract and a 3-6 parted perianth, pistil- 

 late flowers borne singly or in clusters at the ends of the shoots produced 

 in the spring, calyx 4-parted, petals 4, in the sinuses of the calyx, adnate 

 to the ovary, styles 2, short, stigmas 2, large and fringed; drupe large, 

 globose or ovoid, the exocarp somewhat fleshy, fibrous and indehiscent, 



