386 BRITISH FLOWERING PLANTS chap. 



are similarly accommodated, but higher up the axis of 

 the large resting winter bud. 



PiCEA 



P. excelsa (Spruce or Norway Fir). — Commonly 

 planted in Britain, but not native. In this species 

 the true bud scales are inserted on a " common ringlike 

 wall of tissue investing the base of the bud ; when the 

 bud bursts, this ring separates off below, and the whole 

 mass of scales is carried up on the elongating bud, like 

 a cap." ^ There are about twenty species, all in the 

 north temperate region. This is well named excelsa, as 

 it is said to be the loftiest of European trees, reaching 

 a height of 150, or even 180 feet. The cones contain 

 from 300 to 350 seeds. After fertilisation they become 

 pendent, and in the following spring the scales open, 

 the seeds drop out and are wafted away by the wind, 

 after which the rest of the cone drops off whole, and 

 does not break up like that of the Silver Fir. 



The winter buds (Fig. 309) vary greatly in size, 

 those at the apex and immediately beneath it being 

 strongest on the leading branches ; they are also the 

 first to resume growth in the spring. All are covered 

 with numerous scales, which consist of modified leaves. 

 The actual number of scales varies greatly, according to 

 the size of the bud. The accompanying figures would 

 represent buds and scales about the middle of April, 

 after growth has recommenced. The outer scales are 

 the most coriaceous, and elongate slightly or not at 

 all ; the inner ones are transparent and membranous, 

 elongating considerably in spring. The true leaf (Fig. 

 310) consists of a lamina, which becomes disarticulated, 

 when about to fall, from a short persistent portion or 

 pedestal surmounting a basal portion which is decurrent 

 upon the axis. Fig. 311 shows a small, slightly modi- 

 fied leaf — -a form which occurs but sparingly. The 

 basal portion of the bud is covered with broad, tri- 

 angular, acuminate scales (Figs. 312, 313), with a more 



' Marshall Ward, Trees, pt. i. 



