350 DICOTYLEDONES. 



$ -flowers have a superior, 4-leaved perianth, a bicarpellate gynoe- 

 ceum, two styles with stigmas on the internal surface. The ovary, 

 bracteoles and bract all unite together (Fig. 337 E). The fruit is 

 generally a green or black drupe, 1 whose flesh (outer soft portion) in 

 Carya and Juglans ruptures more or less irregularly, and frees the 

 stone ("Walnut"). The stone in Juglans is divided internally by one true 

 (Fig. 337 H) and by several false, low partition walls into several incomplete com- 

 partments, so that the two large cotyledons become lobed and incised to fit like 

 a cast into the irregularities of the inner surface of the stone ; the embryo is 

 exendospermous and covered with a thin testa. THE LEAP SCARS are large and 

 cordate with 3 groups of vascular bundles. The PITH in Juglans and Pterocarya 

 is divided into chambers. The stone ruptures, on germination, along the 

 dorsal suture into 2 valves'; the cotyledons remain underground. In Juglana 

 regia a long row of accessory buds is found on the lowest internode (epicotyl) 

 above the axils of the cotyledons. Pollination by the wind. Both protogynous 

 and protandrous examples of Juglans regia occur. 33 species, mostly in tem- 

 perate North America. USES. Walnuts are obtained from J. nigra and regia ; 

 Hickory from North American species of Carya. The oil- containing seeds of 

 several species are edible. Pterocarya and others are cultivated as ornamental 

 plants. 



FIG. 338. Myrica gale : a young fruit ; x the bracteoles with numerous glands ; b longi- 

 tudinal section of fruit. 



Order 2. Myricacese. To this order belong shrubs or trees 

 which have penninerved, simple, at most lobed or pirmatifid leaves, 

 with or without stipules, and with yellow, aromatic, resin glands 

 (Fig. 338 a). The flowers, situated in catkin-like spikes, are- 

 unisexual and naked, and supported by scale-like floral-leaves. 

 -flower : 4-6 (-16) stamens with short filaments; $ : generally 

 situated singly. The gynoeceum has a short style with 2 long 

 stigmas, and unites with the bracteoles, which form wing-like 

 outgrowths on the ripe drupe as in Pterocarya, in the Juglandaceae 

 (Fig. 338). Cotyledons fleshy (Fig. 338 fy.Myrica; Comptonia. 



1 The fruit of the Walnut is thus a false fruit ; and the term drupe must 

 therefore not be used in the same sense as in the Bosacese. 



