ERICACEAE 249 



interesting distr. of E. See also gen., esp. Rhododendron, Vaccinium, 

 Calluna, Erica). 



The distr. of E. on arctic moors and swamps and on dry moors 

 in warmer regions (almost all grow in peaty soil) would lead us to 

 expect, and we find, esp. in Ericoideae, xero. char. Woody plants 

 from small undershrubs to large shrubs or even trees. Two types 

 of habit that of Ericoideae and that of the remaining tribes. In 

 the latter there are usu. true winter-buds formed (e.g. Rhododendron), 

 even though the 1. may last over the winter. The bud is covered with 

 scale-]., and when its elongation occurs these drop off and a gap is 

 left on the stem; the foliage 1. tend to form rosettes at the ends of 

 the twigs. The 1. are generally elliptical, entire or nearly so, and 

 leathery, frequently hairy. The upper epidermis is stoutly cuticu- 

 larised, and there is often water storage tissue between it and the 

 green tissue. In the Ericoideae there are no true winter-buds or 

 scale-1. ; the plants are evergr., and the whorled 1. needle-like, often 

 through being rolled back on themselves to form a groove or even a 

 chamber on the under side (cf. Empetrum). 



The inrl. commonly terminates a strongly growing shoot, and 

 a sympodial growth tends to be formed. The fls. may be sol., but 

 are more often in racemose groupings, each with a bract and two 

 bracteoles, g , actinom. or slightly zygom. K 4 5 ; C (4 5) or 

 4 5 (Ledeae}, usu. bell-shaped; A 8 10, obdipl., hypog. or rarely 

 slightly epipet.; anthers intr., often with projecting appendages, the 

 thecae often spreading at top, and opening by apical pores; pollen 

 grains in tetrads. Below the gynoeceum is a fleshy disc secreting 

 honey; G (4 5) sup. or inf., 4 5-loc., with axile plac. ; ov. in each 

 loc. I oo, anatr. ; style simple with capitate stigma. Capsule, 

 drupe or berry. Embryo cylindrical, in copious endosp. 



The fls. of the Brit. sp. are mostly bee-rls. with 'loose-pollen' 

 mechanism. The hanging position and the size are suited to bees. 

 The stigma projects so as to be first touched, and in probing for the 

 honey at the base of the fl the bee touches the sta. or their projecting 

 horns, and by thus shaking them causes a shower of pollen to fall 

 from the tips of the anthers. Calluna is partly anemoph. ; Kalmia 

 has a curious explosive mechanism (see C., K., and Erica, &c.). 



[BH. chars. Shrubs and trees, 1. alt., opp., or whorled, exstip , 

 usu. persistent. Infl. various. Fls. reg. $ . K (4 5) or 4 5; C usu. 

 (45), A usu. 8 10, sometimes adnate to base of C., usu. dehisc. 

 by pores; disc various or o ; G (i 12), multi-loc., with style and 

 peltate, capitate or lobed stigma; ov. usu. oo in each loc., anatr., on 

 axile plac. Caps., rarely drupe or berry, with small seeds. Endosp.] 

 Classification and chief genera (after Drude). 



I. RHODODENDROIDEAE (septicidal caps.; seed with 

 ribbed loose coat, often winged; C falling after flowering ; sta. 

 with upright or long adnate anthers, with no appendages): 

 i. Ledeae (polypet. ) : Leclum. 

 i. Rhododendreae (zygomorphic) : Rhododendron, Menzie- 



sia. 



3. Phyllodoceae (actinomorphic) : Loiseleuria, Kalmia, Phyl- 

 lodoce, Daboecia. 



