2 



SILVA OF NORTH AMERICA. cupULiFERiE. 



of a persistent bract, the lateral flowers subtended by similar although smaller bracts, in erect unisexual 

 or androgynous spikes from the axils of leaves of the year or rarely of the previous year. Calyx 

 campanulate, lobed or divided to the base into from four to seven, usually into six, membranaceous 

 lobes or segments. Stamens indefinite, generally from four to six or sometimes ten or twelve ; filaments 

 inserted on the slightly thickened torus, free, filiform, exserted ; anthers ovate, oblong or rarely sub- 

 globose, glabrous or rarely pilose, attached on the back, two-celled, the cells parallel, contiguous, opening 

 longitudinally. Ovary obsolete, or (Pasania) rudimentary, minute and pilose. Pistillate flower solitary, 

 subtended by a caducous bract, bibracteolate, in short or elongated few-flowered spikes from the axils 

 of leaves of the year, or in some species of Pasania scattered at the base of the staminate inflorescence. 

 Calyx usually urceolate, the tube adnate to the ovary, with a short campanulate limb, generally six- 

 lobed or obscurely dentate. Staminodia minute, usually obsolete (Lepidobalanus), or in some species 

 of Pasania developed into abortive stamens inserted on and as many as the lobes of the calyx. Ovary 

 inferior, incompletely three or rarely four or five-celled by the development from the bottom, after 

 fecundation, of thin partitions, inclosed more or less completely by an accrescent scaly involucre ; 

 styles as many as and superposed to the ceUs of the ovary, short or elongated, erect or recurved, 

 terete, or dilated or clavate above, stigmatic on the inner face or at the apex only, generally persistent 



on the fruit ; ovules two in each cell^ attached on its inner angle at or above the base^ or suspended 

 near the apex^ anatropous or semianatropous ; micropyle superior. Nut or gland maturing in one or in 

 two years^ ovoid^ globose^ or turbinate, umbonate at the apex, one-seeded by abortion, surrounded at 

 the base or inclosed in the accrescent cupular involucre of the flower, attached by a large conspicuous 

 raised or depressed circular umbilicus at the base, or (Lithocarpus) by the sides also. Pericarp crusta- 

 ceous or coriaceous, or rarely thick, indurate, granular or bony, indehiscent, of two coats, the inner 

 (Lepidobalanus) thin and membranaceous, or thicker and coated on the inner surface with pale 

 tomentum. Involucral cup woody, free from the nut except at the base, or adnate to it throughout 

 and indehiscent, its scales imbricate, thin or thickened and turbinate or often developed into teeth or 

 spines, or united into crenulate or dentate zones. Seed filling the cavity of the nut, marked at the base 

 or at the apex, or rarely on the side with the abortive ovules, hypogseous in germination.^ Cotyledons 

 thick and fleshy, usually plano-convex and entire, undulate on the back or rarely sinuately lobed, 

 or occasionally united into a solid mass ; radicle minute, superior, included within the base of the 

 cotyledons ; hilum minute, basal or apical.^ 



Nearly three hundred species of Quercus have been described.^ Inhabitants of the temperate 

 regions of the northern hemisphere, they occur also at high altitudes within the tropics, ranging south 

 to the mountains of Colombia in the New World and to those of the Indian Archipelago in the Old 

 World, where, a few degrees below the equator, they find their most southern home. The genus has 

 no representative in central and southern Africa, in South America beyond Colombia, or in the islands 

 of the Pacific, in New Guinea, or Australia. The great centres of distribution of Quercus are the 

 highlands of Central America and Mexico,^ whence it spreads southward with a few species, and 

 northward to British Columbia and the valley of the St. Lawrence River ; and the Indian Archipelago 

 and Malaya,^ whence it ranges to the Philippine Islands ^ and through China ^ and Japan ^ to Saghalin ^^ 

 and Manchuria,^^ through southern India and along the Himalayas ^^ to western Asia,^^ where many 

 species occur, and through the Mediterranean basin ^^ to western and northern Europe, where Quercus 

 is less prolific in species than in other equally temperate regions of the northern hemisphere. In North 

 America, exclusive of Mexico, fifty species of Quercus are now distinguished.^^ With four exceptions 

 they all, under favorable conditions, sometimes assume the habit of trees ; among them are some of 

 the largest and most valuable deciduous-leaved timber-trees of the continent ; and in both the eastern 



and extreme western parts of the country Quercus is often the most conspicuous feature of vegeta- 

 tion.^^ In eastern America at the extreme northern limits of its range the genus is represented by a 

 single species ; the number gradually increases under the influence of a less rigorous climate, and in 



