26 CONTKIBUTIONS FROM THE NATIONAL HERBARIUM. 



DD. BLADES OF THE LEAVES NOT LOBED, THE TEETH ALL EQUAL OR NEARLY SO. 



Leaf blades very asymmetric at the base. 



Teeth of the leaves obtuse; fruit a woody capsule; flowers appearing in autumn, 



bright yellow; shrubs Hamamelis (p. 172). 



Teeth of the leaves acute; fruit not a woody capsule; flowers appearing in spring or 

 summer; trees or rarely shrubs. 

 Leaves glabrous or nearly so, not rough; flowers appearing after the leaves, their 

 peduncles united with a leaflike bract. Fruit small, indehiscent. 



TILIACEAE (p. 202). 

 Leaves very pubescent or rough; flowers appearing with or before the leaves, their 

 peduncles never united with a leaflike bract. 



Flowers in catkins; fruits arranged in a hoplike strobile Ostrya (p. 137). 



Flowers not in catkins; fruits not in strobiles, either a small winged samara or a 



drupe ULMACEAE (p. 140). 



Leaf blades symmetric at the base or nearly so. 



Leaves evergreen, leathery; plants usually less than 30 cm. high. Flowers with a 

 corolla. 

 Fruit a dry capsule; teeth of the leaves not bristle- tipped ; flowers in a terminal 



long-stalked cluster; petals distinct Chimaphila (p. 221). 



Fruit a fleshy capsule; teeth of the leaves bristle-tipped; flowers axillary, solitary; 



petals united Gaultheria (p. 222), 



Leaves not evergreen, or, if so, (in Ilex) the plants large shrubs or trees; plants 



usually much more than 30 cm. high. 



Flowers all or mostly in catkins; fruit dry or, if fleshy, a cylindrical multiple fruit 



(mulberry), never a capsule, sometimes a nut inclosed in a spiny or rough 



bur; flowers appearing with or before the leaves; corolla none. 



Fruit a nut inclosed in a spiny or warty bur. Trees or shrubs; teeth of the 



leaves often bristle-tipped FAGACEAE (p . 137). 



Fruit not a nut inclosed in a spiny or warty bur. 



Leaves aromatic, conspicuously gland-dotted; fruit a small spheric nut cov- 

 ered with white wax. Leaves oblanceolate; shrubs. 



Myrica (p. 135). 

 Leaves not aromatic and gland-dotted; fruit not wax-covered. 



Fruit a small capsule; seeds long-hairy. Trees or shrubs, often with large 



stipules SALICACEAE (p. 132). 



Fruit not a capsule; seeds not hairy. 



Fruit juicy or in spheric heads MORACEAE (p. 141). 



Fruit dry, never in spheric heads BETTJLACEAE (p. 136). 



Flowers not in catkins; fruit often a capsule, never a nut or a multiple fruit; 

 flowers mostly appearing after the leaves; corolla present. 

 Flowers sessile in dense heads on a common receptacle surrounded by an invo- 

 lucre of bracts; fruit an achene, bearing at the top a row of bristles. Corolla 



gamopetalous; shrubs Baccharis (p. 283). 



Flowers not sessile in dense heads; fruit not an achene. 



Corolla of united petals; fruit a depressed, 5-lobed or 5-angled capsule. Flow- 

 ers in simple or panicled racemes; shrubs; stipules none. 



ERICACEAE (p. 222). 

 Corolla of distinct petals; fruit not a depressed 5-lobed capsule. 



Flowers solitary or clustered in the axils. Fruit a berry-like 4-8-seeded 

 drupe; trees or shrubs; leaves sometimes persistent and with spiny teeth. 



AQTJIFOLIACEAE (p. 199). 



