632 RUTACEAE Zanthoxylum 



137. RUTACEAE .hiss. Rue Family 



Leaves pinnate; fruit red, a 1- or 2-seeded capsule 3990. Zanthoxylum, p. 632. 



Leaves 3-foliolate; fruit yellowish, a samara 4069. Ptelea, p. 632 



3990. ZANTHOXYLUM L. 



1. Zanthoxylum americanum Mill. Northern Prickly Ash. Map 

 1305. More or less frequent in the lake area; infrequent in the Tipton Till 

 Plain; and south of the Tipton Till Plain found locally only in wet 

 woods and on dry wooded slopes. On account of its ability to sucker it is 

 usually found in dense colonies. 



Que. to Minn., southw. to Va., Ky., Mo., and e. Kans. 



4069. PTELEA L. 



Bianchlets glabrous 1. P. trifoliata. 



Branchlets pubescent la. P. trifoliata var. Deamiana. 



1. Ptelea trifoliata L. (Ptelea inesochom Greene.) COMMON HoPTREE. 

 Map 1306. An infrequent shrub in all parts of the state. It is usually 

 restricted to the alluvial banks of streams but it is found sometimes on 

 the tops and slopes of rocky bluffs. The under surface of the leaflets is 

 more or less pubescent on unfolding, becoming more or less glabrous at 

 maturity. Some are glabrous with the exception of a few hairs in the 

 axils of the veins and on the petioles ; others have a straggling pubescence ; 

 and in nearly a fourth of our specimens the under surface is thickly pubes- 

 cent. The pedicels of the flowers are likewise more or less densely pubescent 

 at flowering time, and at maturity they become glabrous or remain more 

 or less densely pubescent. There is no correlation of pubescence of the 

 leaflets and pedicels, although the leaflets that are very pubescent at 

 maturity also have pubescent pedicels, but nearly glabrous leaflets may 

 have densely pubescent pedicels. Plants with leaflets remaining pubescent 

 until maturity are Ptelea trifoliata f. pubescens (Pursh) Fern. (Rhodora 

 38: 233. 1936). The pubescent form is much less frequent than the 

 glabrate form and has no definite geographic range in Indiana, although 

 most of our specimens are from the southern part of the state. 



Conn., s. Ont. to Minn., southw. to Fla. and Kans. 



la. Ptelea trifoliata var. Deamiana Nieuwl. This variety is found only 

 on the dunes near Lake Michigan where, for the most part, it displaces the 

 species although I have seen both variety and species growing together. 

 We have both the variety and species of the same age growing at Bluff ton. 

 The variety grows more slowly and is more widely spreading than the 

 typical form. 



138. SIMARUBIACEAE DC. Quassia Family 



4124. AILANTHUS Desf. 



1. Ailanthus ALTissiMA (Mill.) Swingle. (Ailanthus glandulosa 

 Desf.) Ailanthus. Map 1307. In waste places in cities and towns, in a 



