Jones: Flora of Illinois, 93. Polygalaceae 173 



1. Zanthoxylum L. 



Z.. americaniim Mill. Prickly-ash. Woods and thickets, common through- 

 out 111., except the s. counties. Apr. -May. 



2. Ptelea L. 



P. trifoliata L. Hop-tree. Wafer-ash. Along streams and at the edges of 

 woods, not uncommon. May-July. Plants with pubescent branchlets have been 

 named var. deamiana Nieuwl. [P. trifoliata var. mollis sensu auth., non T. 8C 



G.} 



92. SiMARUBACEAE DC. — Quassia Family 

 1. Ailanthus Desf. 

 A. altissima (Mill.) Swingle. Tree of Heaven. Waste ground and edges 

 of woods, common; native of China. June-July. [/I. glandulosa Desf.] 



93. Polygalaceae Reichenb. — Milkwort Family 

 1. Polygala L. — Milkwort 



1. Plants perennial or biennial, usually several-stemmed (except P. pauci- 

 folia) ; leaves alternate. 



2. Flowers 1-3, terminal, rose-purple to white, 1.5-2 cm. long; leaves oval, 

 near the summit of the stem, the lower scale-like; rhizomes slender, 

 bearing inconspicuous cleistogamous flowers; moist woods, n.e. 111., 



rare; without locality, Moffatt; Vasey. May-June. Fringed Polygala 



P. pauafolia Willd. 



2. Flowers several or many, 3-6 mm. long, in terminal racemes. 



3. Leaves lanceolate to ovate, acuminate, 5-20 mm. w'de; flowers greenish 

 white; racemes compact; wings orbicular-ovate, 2-3 mm. long; plants 

 perennial; cleistogamous flowers absent; wooded banks, or roadsides, 



locally throughout 111. May-Sept. Seneca Snakeroot P. senega L. 



3. Leaves linear-oblanceolate, acutish, 2-6 mm. wide; flowers rose-purple 

 to pink; racemes loose; wings obovate, 4-6 mm. long; plants biennial, 

 with small cleistogamous flowers usually present at base; sandy soil, 

 n. III. June-Aug P. polygama Walt. 



1. Plants annual, single-stemmed; leaves linear or linear-oblanceolate. 

 4. Racemes capitate, obtuse, more than 5 mm. thick. 

 5. Leaves alternate. 



6. Stem glaucous; leaves linear-subulate, distant; petals united into a 

 tube about 5 mm. long; wings linear, less than half the length of 



the keel; prairie soil, in the n. half of the state, rare. July-Sept 



P. incarnata L. 



6. Stem leafy, not glaucous; petals not united into a long tube; wings 

 oval, equalling or exceeding the keel; fields, meadows, and open 



woods. July-Sept. [P. viridescens L.} P. sanguinea L. 



5. Leaves in whorls of four, linear-oblanceolate; wings acuminate; sandy 



soil in the n. half of the state. July-Sept P. cniciata L. 



4. Racemes slender, cylindrical or linear, tapering, less than 5 mm. thick. 



