402 THE CATKIN FAMILY. 



LXXIII. AMENTACE^. THE CATKIN FAMILY. 



Trees or shrubs, with alternate fiat leaves, usually with sti- 

 pules, and small, unisexual flowers, in cylindrical, oblong, or 

 globular spikes, called catkins, which are usually dense with 

 closely packed, scale-like bracts, rarely loose, or with minute 

 deciduous scales. Stamens in the male catkins 2 or more 

 (rarely united into 1) within each scale, usually accompanied 

 by 2 or more smaller scales, either distinct or forming in a 

 few cases an irregular or oblique perianth, or rarely entirely 

 deficient. Female catkins either like the males, with 1, 2, or 

 3 flowers within each scale, or reduced to a sessile bud, with 2 

 or 3 flowers in the centre, surrounded by the lower empty 

 scales of the catkin ; within each scale are also usually 2 or 3 

 inner scales. Perianth none, or closely combined with the 

 ovary, with a minute, free, or entire toothed border. Ovary 

 1-celled or several-celled, with 2 or more styles, always result- 

 ing in a 1-celled fruit, which is either a 1 -seeded nut, or a 

 several-seeded capsule opening in 2 valves. The catkin-scales, 

 or the inner scales, or both, usually persist, and are sometimes 

 enlarged into an involucre, either around or under the fruit, 

 Seeds without albumen, at least in the British genera. 



An extensive family, widely distributed over the globe, but chiefly in 

 the temperate regions of both hemispheres, where it often constitutes 

 a large proportion of the forest-trees. Minor differences, chiefly in 

 the female flowers, have required its division into several independent 

 families, but for the purposes of this work it forms a natural as well as 

 a distinct group. Among the few British plants that have their inflor- 

 escence at all resembling catkins, Ilippophae is readily distinguished by 

 the berry-like fruits and scurfy foliage, Ulmus by its hermaphrodite 

 flowers, Humvlus by its opposite leaves, and Coniferce by their peculiar 

 foliage, independently of the important character of the naked seeds. 



Tree or shrub, in flower. 

 Scales of the male catkins broad, imbricated. Anthers longer than 



their filaments. 



Male and female catkins short, sessile, and erect . . 1. MYRIOA. 



Male catkins cylindrical, usually pendulous. 

 Three distinct flowers, each with 4 stamens, under each scale of 



the male catkins. Female catkins small, ovoid . . . 2. ALNUS. 

 Stamens 6 to 12 within each scale, not in distinct flowers. 

 Scales of the male catkins stalked. Female catkins cylindrical 8. BETULA. 

 Scales of the catkins sessile. 

 Stamens at the base of the scale. Female catkins loose, with 



narrow scales 4. CARPINU& 



Stamens on the scale itself. Female catkins minute, ses- 

 sile and budlike .... .... 6. COBYLUS. 



Scales of the male catkins narrow-linear, or divided, or very minute. 



An. hers small, on slender filaments. 



Flowers dioecious. Catkins both male and female, cylindrical, com- 

 vact, and usually silky -hairy. 



