OAK 



A Staminate and a Pistillate Flower 

 of Scarlet Oak, Quercus coccinea ; 

 enlarged. 



of the year. There is no corolla. The calyx is bell-shaped 

 and divided into four to six divisions. The stamens, usually 

 four to six, with exserted filaments and oblong two-celled 

 anthers, are borne on the torus. The ovary has aborted. 



The pistillate flowers are subtended by a quick falling bract 

 and are borne in few-flowered spikes, or on solitary peduncles 

 produced from the axils of the 

 leaves of the year. The calyx 

 is urn-shaped and grows fast to 

 the ovary. The stamens have 

 aborted. 



The ovary is inferior, incom- 

 pletely three-celled and inclosed 

 more or less by a growing scaly 

 involucre which in time develops 

 into the acorn cup. Styles are 

 usually three, short or long, erect or curved, generally per- 

 sistent on the fruit. There are two ovules in each cell, but 

 all save one fail to be nourished. The nut is a fruit formed 

 by the adhesion of an ovary to the calyx and matures either 

 the first or second year ; it is always surrounded at the 

 base, or more or less inclosed, by a woody involucre called 

 the cup. The acorn cup is of woody texture made up of a 

 large number of tiny scales which have grown together, 

 sometimes entirely, sometimes with free tips. The seed fills 

 the nut. The cotyledons are thick and fleshy, the radicle 

 minute. An acorn should never be allowed to become dry if 

 it is desired that it should germinate, for the vital principle 

 is fleeting. 



American oaks in the popular mind have the reputation of 

 being slow growers, but this is based upon the habit of two or 

 three species rather than upon the habit of the family. The 

 White and the Bur Oaks grow slowly. The Scarlet Oak is mod- 

 erately slow. But the Black, the Swamp White, the Pin, and 

 the Red, under favorable conditions, will all grow rapidly in 

 their youth. Probably most oaks require a century to reach 

 maturity ; they rarely bear acorns under twenty years of age 



325 



