RECEPTION OF FLOWER-SEEKING ANIMALS AT THE FLOWER. 225 



it turns all its flowers away from the shaded side where insects are not abundant, 

 and directs them towards the sunny meadow swarming with bees and humble-bees. 

 Some Labiates belonging to the genera Salvia and Satureja turn all their flowers 

 one way only when they stand close to a steep wall. When they are equally 

 exposed on all sides their flowers are directed towards all the points of the compass. 

 A similar behaviour is observable in many plants which grow on the narrow 

 mouldings of old, ruined walls, or on the ledges of steep rock faces, as, for instance, 

 in the Snapdragon {Antirrhinumn, majus) and in Haberlea rhodopensis of the 

 Balkans; both of these turn their flowers away from the wall or rock, even when 

 these backgrounds are well warmed and lighted by the sun. 



The visitors to laterally - directed flowers include Syrphidse, Owlet-moths, 

 Hawk-moths, Humming-birds — indeed all animals which suck honey whilst hover- 

 ing in front of the flowers. As they require no platform, we find all flowers of this 

 type destitute of anything of the kind. 



Flowers which are visited by sun -birds (Nectarinise), humming-birds and by 

 night-flying moths are likewise destitute of plates, ridges, fringes, pegs, or knobs 

 on which the animals might alight or cling. The lobes of the corolla which close 

 the flower in bud take, on opening, a position in which they are useless as perches; 

 indeed they bend right back so as to impede the hovering animals as little as 

 possible as they suck up the honey with their probosces or bills. As examples may 

 be mentioned the Honeysuckle (Lonicera Gaprifoliwrri), the Orchid Habenaria 

 hifolia visited by Hawk-moths, and Melianthus major sought by small honey- 

 drinking sun- birds (c/. figs. 258 9,10,11.12, is )_ When a well-developed edging or fringe 

 is present in flowers adapted to crepuscular Lepidoptera and Humming-birds, as in 

 Mirabilis longifiora, Nicotiana affinis, Posoqueria fragrans, Narcissus poetious^ 

 and (Enothera biennis, it serves from its delicacy and position not as a platform, 

 but, in virtue of its conspicuous white or yellow colour, as an attractive organ visible 

 at a considerable distance in the gloaming. 



Otherwise is it with flying animals which must first alight on the flower and 

 then penetrate to the concealed honey. Like doves entering a dove-cote, they 

 require a platform, and in point of fact such a provision is found in such laterally- 

 directed flowers as depend on this class of visitor. 



In Epipogiv/m aphyllum the " column " pointing obliquely downwards forms a 

 convenient platform for humble-bees (Bombus lucorutn, cf. figs. 257 ^^'i^'^^). But 

 on the whole the column of Orchid-flowers is rarely used in this way. Very often 

 the stamens or style project well beyond the margin of the flower and serve this 

 purpose, as, for instance, in the Horse Chestnut (^sculus), many Liliacese (Funkia, 

 Anthericum, Paradisia, Phalangium), Viper's Bugloss (Echiura), Dictamnus and 

 Pmderota, similarly in the large-flowered Speedwells {Veronica, cf. fig. 257 ^)_ 

 More frequently, however, the margin of the perianth or corolla is modified for this 

 purpose. Especially noteworthy in this respect are the Aristolochias, on the fiowers 

 of which there exists an almost endless series of sometimes flattened, sometimes 

 perch-like, alighting-platforms. In Aristolochia ringens (fig. 242, p. 166), it 



Vol. II. 65 



