ALLUREMENTS OF ANIMALS FOR THE DISPERSION OF POLLEN. 



181 



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

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

 aceae, Primulaceae, Boraginaceae, and Campanulacese (Nicandra, 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 ^ ; finally in the Mammillarias, belonging to the 

 Cactaceae (see fig. 246 ^). 



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



y 



Fig. 251.— Concealment of Honey. 



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

 from above. 3 Flower of Phygelius cape7isis ; the front half cut away. * Flower of Trici/rtes 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 Uypecouin grandiflorum 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, stifl*, 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. 



