43 8 THE ERICALES 



familiar plants of bogs and woods as the sweet-pepper bush 

 (Clethra), wintergreen (Chimaphila), Labrador tea (Ledum), 

 Rhodora. Leueothoe, rosemary (Andromeda), leather leaf 

 (Chamaedaphne) , arbutus (Epigaea), checkerberry (Gaul- 

 theria), bearberry (Arctostaphylos) , huckleberry (Gaylussacia), 

 blueberry (I'aeeiniitm) , heather (Calluna), cranberry (O.ry- 

 coccus). The flowers of the heaths are very characteristic and 

 sharply distinguished from other orders. More frequently they 

 consist of five regular whorls of five members each, anthers 

 usually opening by pores and often provided with two horn-like 

 appendages, and the pistil is composed of five carpels, the ovary 

 maturing as a capsule or berry (Fig. 326). The lack of ad- 

 hesion between the whorls is an important feature of the order 

 as contrasted with other sympetalae, each set being as a rule 

 separately attached to the receptacle. While the sympetalous 

 corolla is a step in advance of previous types, it is evident that 

 these regular hypogynous flowers are in other respects of a rather 

 simple character. This feature is further illustrated in some 

 of the genera like Clethra, Mouotropa and Pyrala where the 

 free or slightly fused petals form a very natural transition from 

 the Choripetalae (Figs. 327, A ; 326). 



The simpler forms of flowers are illustrated in Pyrola with 

 its regular hypogynous and polypetalous flowers, though some 

 species show a slight cohesion of the petals. The stigmas are 

 mature with the opening of the flower while the anthers are 

 bent back out of the way, their filaments being held under con- 

 siderable tension by the petals (Fig. 326, A, B). A bee laden 

 with spores would effect a crossing as soon as he alighted upon 

 the flower, but in probing after the nectar he presses back the 

 petals, thus releasing the anthers which snap down, spilling the 

 spores upon him. Doubtless autogamy results in many of these 

 forms if crossing fails owing to the expansion of the petals 

 which would release the stamens, and the drooping of the flower 

 (Fig. 326, C, D). 



Other genera show varying degrees in the cohesion of the 

 petals but in the majority of cases, tubular corollas appear (Fig. 

 327, C) as in the Leueothoe, bearberry, Andromeda, blue berries. 



