ERICACEAE ^ 



2. Tribe Andromedeae. 



521. Andromeda L. 



Flowers usually homogamous, with concealed nectar secreted at the base of 

 the ovary. 



1759. A. Polifolia L. (Loew, 'Bliitenbiol. Floristik,' p. 270 ; Warming, 'Arkt. 

 Vaxt. Biol.,' pp. 19-21.) In this species five or more delicate pendent flowers are 

 arranged in an almost umbellate inflorescence at the end of the stem. The bright- 

 red peduncles are about three times as long as the flowers, which are 5 mm. in 

 length and of about the same breadth. The bell-shaped corolla-tube is red in 

 colour, while the teeth are white with five reddish longitudinal streaks. Loew 

 describes the bell as pos- 

 sessing a pentagonal opening 

 about i^ mm. broad, formed 

 entirely by the short reflexed 

 corolla-lobes. The inside of 

 the corolla is clothed with 

 hairs, and the filaments are 

 also hairy. In this way the 

 nectar secreted by ten swell- 

 ings at the base of the ovary 

 is protected, and pollen is 

 prevented from falling out of 

 the flower. 



The stigma is receptive 

 when the flower opens, 

 is situated in the opening 

 of the corolla, and pro- 

 jects beyond the dark-brown 

 anthers, which Loew says 

 mature simultaneously in the 

 March of Brandenburg. In normal flowers the anther-pores are directed inwards, 

 and the appendages outwards. The nectar can be reached by a proboscis of 

 4-4^ mm. long. Warming states that in the arctic plants he examined automatic 

 self-pollination could be eff'ected, should insect-visits fail, by fall of pollen on to 

 the stigma, which completely fills the narrow opening of the corolla. Lindman, 

 whose observations were made on the Dovrefjeld, says that the stigma becomes 

 receptive in the bud, and he sometimes found pollen-grains on its edge, which 

 is beset with five small rounded projections. In other cases he noticed pollen 

 on the under-side of the stigma, suggesting insect-visits. 



Visitors. Alfken (Bremen) noticed 2 humble-bees (Bombus lapidarius Z. $, 

 not freq., skg., and B. muscorum F. 5, freq., skg., persistently visiting this species, 

 but avoiding other nectar-yielding plants, e.g. Ajuga, growing close by) and a butter- 

 fly (Thecla rubi Z., very freq., skg.). 



D 2 



Fig. 221. Androineda Polifolia^ L. (after E. Warming). A. Dia- 

 gram of a flower with its bract and bracteoles. B. The end of 

 a flowering branch ; below are two foliage-leaves with small leaf-buds 

 in their axils; above these a third foliage-leaf has been removed to 

 show the further developed leaf-bud in its axil. Above this again are 

 two bracts respectively subtending a flower-bud {f) and a fully 

 developed flower; between these are closely apposed bracteoles (x 3). 

 C. Longitudinal section through a mature flower. D. A flower seen 

 from above (x 4). E. An anther (x 20). F. Pollen. G. Ovary 

 with nectary and 2 stamens (x 8). H^ I. End of the style, and 

 stigma. 



