62 BETULACEAE 



CORYLUS (Tournefort) Linnaeus 

 Hazelnuts Filberts 



This is a genus of shrubs or, in other lands, small trees, which 

 bear alternate, thin, doubly toothed, broad-bladed leaves. The 

 staminate catkins arise singly or in fascicles from scaly buds on 

 year-old twigs, and the staminate flowers bear 8 stamens and 2 

 scaly bractlets attached to the inner face of the catkin scale. 

 The pistillate flowers emerge, several together, from a scaly 

 bud on the tip of an early, leafy shoot. The ovary in the flower 

 is tipped with the short limb of the adherent calyx scales. One 

 of its 2 ovules is sterile. The style is short, with 2 red, elongated, 

 slender stigmas. The fruit, an ovoid or globose nut, is inclosed 

 in a cup made up of 2 enlarged, leafy or woody bracts. 



This genus is, in America, represented by two native species. 

 The filbert of commerce is a Japanese species. 



Key to Hazelnut Species 



Twigs and petioles glandular-bristly, fruit husk open to the top 

 of the nut, its bracts toothed C. americana 



Twigs and petioles not glandular-bristly, fruit husk densely 

 bristly, closed, and prolonged into a narrow, tubular beak 

 C. cornuta 



CORYLUS AMERICANA Marshall 

 Hazelnut American Hazel 



The Hazelnut, fig. 9, is a small, branched shrub generally 

 3 to 5 feet high, or occasionally of ranker growth and 15 or 

 more feet tall. Its alternate, simple, 2-ranked leaves, often as 

 much as 6 inches long by 4 inches wide but usually 3 by 2 

 inches, vary from nearly orbicular to the more usual ovate, 

 and have acuminate tips, slightly obliquely cordate bases, 

 doubly serrate margins, and teeth that are short and blunt. 

 The upper surface is more or less pubescent, the lower thickly 

 so, and the veins and veinlets are at times more or less densely 

 overgrown with stalked glands. The rather stout petioles are 

 1/^ to 1 inch long, pubescent, and more or less covered with 

 glandular hairs. The gray or brown, zigzag branchlets, at first 

 pubescent and also covered by green or reddish glandular hairs, 

 the latter often persisting, are moderately stout or slender, 

 terete, and contain continuous, pale, somewhat 3-sided pith. 



