QJJERCUS 



Quercus, Linnaeus, Gen. PL 291 (1737), Sp. PL 994 (1753); Bentham et Hooker, Gen. PI. 407 



(1880). 

 Lithocarpus, Blume, Bijdr. Fl. Ned. Ind. 526 (1825). 

 Syncedrys, Lindley, Introd. Nat. System, 441 (1836). 

 Cydobalanopsis, Cyclobalanus, and Pasania, Oersted, in Vidensk. Medd. Kjobenh., 1866, pp. 77-81. 



Trees or shrubs, belonging to the order Fagaceae. Buds usually clustered at the 

 ends of the branchlets, covered with numerous scales, imbricated in five ranks, and 

 marking when they fall the bases of the branchlets with ring-like scars. Leaves 

 either deciduous in autumn or in the following spring, or persistent two to four 

 years ; simple, alternate, five-ranked, stalked ; lobed, toothed, or entire. 



Flowers unisexual or rarely perfect, monoecious, apetalous, in spikes or catkins. 

 Staminate flowers : calyx four- to seven-lobed ; stamens four to six, rarely two, ten, 

 or twelve, with slender filaments. Pistillate flowers, each enclosed in an involucre 

 of imbricated scales ; calyx six-lobed ; ovary with two ovules in each of the three 

 to five cells ; styles three to five. 



Fruit, a nut (the acorn), ripening in one or two years, with a large pale scar at 

 the base, more or less surrounded by the woody cupule, resulting from the growth 

 of the involucre of the flower. The acorn contains one seed, which is marked at the 

 base, apex, or sides by the aborted ovules ; cotyledons thick and fleshy, not raised 

 above the ground on germination. 



About 275 species of oak have been described, inhabiting the temperate regions 

 of the northern hemisphere and high altitudes within the tropics, ranging in the New 

 World southwards to Colombia, and in the Old World to the Malay Archipelago. 



The genus may be divided into the following sections, one of which, Pasania, 

 is now considered by many botanists to be a distinct genus. 



* Staminate flowers in pendulous, slender, clustered spikes. Styles flattened, 

 with the stigmatic surface on the upper side. 



I. Lepidobalanus, Endlicher. 



Staminate flowers solitary. Pistillate flowers in few - flowered separate 

 spikes. Cupule of the fruit saucer- or cup-shaped, with imbricated scales, free 

 at their apices. 



This section includes, with one exception (Q. densiflora), all the oaks of 



North America, Europe, northern Africa, and western Asia ; and a large number 



1215 



