ALLUREMENTS OB^ ANIMALS FOE THE DISPERSION OF POLLEN. 



181 



Sometimes the stamens are so fashioned and disposed as to form an overarching 

 roof or do.ne above the honey-secreting base of the flower, e.g. in numerous Solan- 

 aceae, Primulacese, Boraginacese, and Campanulacese (Mcandra, Cyclamen, Borago, 

 Campanula, Phyteuma); very beautifully also in the Willow-herb (Epilobium 

 angustifolium), in Gladiolus, and in the small-flowered Cinquefoil (Potentilla 

 micrantha) pictured in fig. 246 1; finally in the Mamillarias, belonging to the 

 Cactacese (see fig. 246 ^). 



The hiding of the nectaries by a massing together of the stamens is effected in 



Fig. 251. — Concealment of Honey. 



1 Stigma of Gentiana Bavarica which closes the corolla-tube, removed from the flower. 2 Flower of the same plant seen 

 from above, s Flower of Phygelius capensis ; the front half cut away. * Flower of Tricyrtes pilosa, the anterior part 

 cut away, s One of the two inner petals of Hypecoum grandiflorum seen from the side adjacent to the ovary. ^ Flower 

 of Bypecoutn grandifiorum showing the two inner petals standing close to the ovary. 



a very strange manner in some white-flowered Crow-foots, e.g. in Ranunculus 

 glacialis. In these plants the honey is secreted in small pits on the upper side of 

 the petals close above the yellow, thickened claw (see fig. 246^'^'^). In front of 

 this pit is a scale which rises from the plane of the petal at an angle of 40°— 50°. 

 On and near this scale lie the numerous stamens arranged in several whorls radiat- 

 ing out from the centre of the flower. A small nectar-cavity is thus formed at the 

 base of each petal to which only those insects strong enough to press up the over- 

 hanging stamens and the scale can gain entrance. In the flowers of the Atragene 

 alpina the stamens are hollowed into a groove in which a quantity of honey is 

 secreted (see fig. 246 *). But as in each flower there are many whorls of stamens — 

 those of the outer whorls always covering and being attached to the backs of the 

 inner ones (see fig. 246 '), and as all the stamens are held together outside by a 

 whorl of erect, stiff, spoon-shaped leaves (see fig. 246 °) — all these channels form, as 

 it were, many small, closed, nectar-cavities only to be opened by powerful insects. 



