AMENTACE^. 757 



a. Pedunculate British 0. (Q. Robur pedunculated, Eng. Bot. 1. 1342.) 

 Leaves sessile or shortly stalked. Fruits either clustered or spiked, 

 above the middle of a peduncle varying from 1 to 5 or even 6 inches 

 long. The commonest Oak over the greater part of England and the 

 lowlands of Scotland. In the hilly parts of the west and north it is 

 less abundant and less constant in its characters, and sometimes wholly 

 wanting. 



b. Sessile British O. (Q. Robur sessiliflora, Eng. Bot. t. 1845.) 

 Leaves on footstalks varying from J to 1 inch long. Emits solitary or 

 clustered, either closely sessile on the branch or borne on a short pe- 

 duncle, very rarely attaining an inch. Frequently scattered in woods 

 of the pedunculate variety, and then pretty constant in its characters, 

 rarely constituting the mass of oak-woods in the lower parts of Britain, 

 but in JN~orth Wales and the hilly parts of northern England it is the 

 commonest of the two, and very much more variable. 



YIIT. WILLOW. SALIX. 



Leaves variable, but not triangular nor rhomboidal. Stipules often 

 very conspicuous, but sometimes small or deficient on other branches 

 of the same plant. Elowers dioecious, in cylindrical, usually silky- 

 hairy catkins, with small, entire scales. Stamens in the males 2, rarely 

 3, 5, or even more, or united into one, with slender filaments and small 

 anthers, and a gland-like scale either between the stamens and the 

 axis, or more rarely between the stamens and the catkin-scale, or two 

 scales, one on each side, but no perianth. Female flowers solitary 

 within each scale, with a gland-like inner scale between the ovary and 

 the axis. Ovary conical, sessile or stalked, one-celled, with several 

 ovules inserted on 2 short parietal placentas. Style forked, each lobe 

 entire or shortly 2-lobed. Fruit a conical capsule, opening in 2 valves. 

 Seeds several, minute, with a tuft of long, white, silky hairs. 



A vast genus, widely spread over the world, but particularly abun- 

 dant in the northern hemisphere, from the tropics to the Arctic zone, 

 ascending high upon alpine summits, and in low countries chiefly in- 

 habiting wet or sandy situations. The great variations in the shape 

 of the leaves of many species, and the difficulty of matching the male 

 and female specimens, or the young and old leaves of those species which 

 flower before the leaves are out, have produced a multiplication of sup- 

 posed species, and a confusion in their distinction, beyond all prece- 

 dent. The following fifteen are all that appear to be truly distinct 

 among the British ones ; at the same time, reliable observations are 

 wanting on the degree of variation of particular characters, especially 



