CUPULIFER^E. (OAK FAMILY.) 331 



1. L. Canadensis, Gaudichaud. Leaves orate, pointed, strongly feather- 

 veined, long-petioled ; stipule single, 2-cleft. — Throughout the Atlantic 

 States, and coming within our borders" at the northwest. 



5. PARIETARIA, Tourn. Pellitoky. 



The staminate, pistillate, and perfect flowers intermixed in the same invo- 

 lucrate-bracted eymose axillary clusters. — Diffuse or tufted herbs, with entire 

 3-ribbed leaves and no stipules. 



1. P. Pennsylvania, Muhl. Low, simple or sparingly branched, 

 minutely downy : leaves oblong-lanceolate, thin, veiny, roughish with opaque 

 dots : flowers shorter than the leaves of the involucre. — From Colorado to 

 Nevada and eastward across the continent. 



6. HUMULUS, L. Hop. 



Sterile flowers with 5 sepals and 5 erect stamens. Fertile flowers in short 

 spikes with leafy imbricated bracts, each 2-flowered. Akene invested with the 

 enlarged scale-like calyx. — Twining rough perennials, with stems almost 

 prickly downwards, mostly opposite heart-shaped and palmately 3 to 7-lobed 

 leaves. 



1. H. LupuTuS, L. Leaves commonly longer than the petioles: the 

 fruiting calyx, akene, etc., sprinkled with yellow resinous grains, giving the 

 bitterness and aroma of the hop. — In the mountains from New Mexico to 

 British America and eastward across the continent. 



Order 74. CUPULIFERJE. (Oak Family.) 



Trees or shrubs, with alternate and simple straight-veined leaves, 

 deciduous stipules, and monoecious flowers, both kinds of flowers in 

 catkins, or the fertile solitary, clustered, or spiked, the 1-celled, 1-seeded 

 nut with or without an involucre. 



Tribe I. Both kinds of flowers in scaly catkins, 2 or 3 under each bract, and no involucre 

 to the naked often winged small nut. — BETULE.fi. 



1. Betula. Stamens 2, with bifurcate filaments and separate anther-cells. Bracts 3-lobed, 



becoming coriaceous and caducous. Nutlet broadly winged. 



2. Alnus. Stamens 4: anther-cells contiguous. Bracts entire, becoming woody, per- 



sistent. Nutlet not winged. 



Tribe II. Sterile flowers destitute of a true calyx, consisting of several stamens included 

 under and more or less adnate to a bract : filaments short ; anthers 1-celled. Fertile 

 flowers in a scaly bud or catkin, two under each fertile bract, each with one or more 

 bractlets, which form a foliaceous involucre to the nut. — Coeyle*. 



3. Corylus. Bract of staminate flower furnished with a pair of bractlets inside. Invo- 



lucre leafy-coriaceous, enclosing the large bony nut. 

 Tribe III. Sterile flowers with a distinct 4 to 7-lobed calyx, including 3 to 20 stamens: 

 filaments exserted ; anthers 2-celled. Fertile flowers one or few enclosed in a cupule 

 consisting of bracts variously consolidated. — Quercine^e. 



4. Qnercus. Sterile flowers in slender catkins. Cupule 1-flowered, scaly and entire ; 



nut hard and terete. 



