170 Proceedin^^s of the Ohio State Academy of Science 



1 . Leaves acute, with 6-10 pairs of lateral veins ; nutlets smooth ; 

 umbels peduncled ; flowers bisporangiate. R. caroliniana. 



1. Rhamnus cathartica L. Common Buckthorn. A 

 shrub or small tree with black injurious fruit. Somewhat thorny 

 and used for hedges. Introduced from Europe. Eastern states. 



2. Rhamnus caroliniana Walt. Carolina Buckthorn. A 

 tall thornless shrub or small tree with a globose sweet drupe. In 

 wet soil- Va. and Ohio to Kan., Fla., and Tex. 



Order, Malvales. 



Tiliaceae. Linden Family. 



6i. Tilia L. Linden. 



Trees with 2-ranked inequilateral, serrate leaves, the dry 

 drupaceous fruit in cymose clusters, the peduncle subtended by 



a broad membranous bract. 



\. Petals with scales at the base. 2. 



1. Petals without scales at the base; leaves glabrous or nearly so; 



cultivated. T. europaea. 



2. Leaves glabrous or nearly so on both sides. T. americana. 

 2. Leaves glabrous above, pubescent beneath. T. pubescens. 



2. Leaves glabrous above, silvery-white beneath. T. heteropJiylla. 



1. Tilia americana L. x\merican Linden. A large, 

 straight-trunked tree with spreading branches. Inner bark very 

 tough ; used for mats and coarse rope. Wood soft and very 

 white, light and uniform in texture, not liable to crack ; called 

 "basswood ;" used for wooden-ware, cabinet-work, trunks, pan- 

 elling of carriages, in cooperage, and for toys. The bark and 

 wood of the other lindens are much the same. In rich soil, on 

 bluffs, and along river bottoms. N. B. to Ga., Manitoba, Kan., 

 Tex., and Ohio. 



2. Tilia pubescens Ait. Downy Linden. A small tree 

 growing in moist soil, mostly along the coast. L. I. to Fla., west 

 to Tex. 



3. Tilia heterophylla Vent. White Linden. A tree with 

 larger leaves than either of the preceding species. N. Y. to Fla., 

 Ala., 111., Ky., Tenn., and Ohio. 



