io6 Flowers and their Unbidden Guests. 



held together byan external whorl of upright rigid spoon- 

 shaped petals, the grooves at the base of the filaments 

 are converted into so many small closed nectar-cavities, 

 which are utterly inaccessible to the weaker insects, 

 and can only be forced open by strong humble-bees, who 

 thrust the closely packed stamens asunder. 



Thus far it has been some part either of the perianth 

 or of the androecium that has completely closed up the 

 nectar-cavity. The occlusion may, however, also be 

 effected by the gynaecium. In such cases the usual 

 arrangement is that the ovary plugs up the tubular 

 or funnel-shaped part of the perianth above the nec- 

 tariferous space. In Phygelius capensis^ for instance, 

 the extraordinarily abundant nectar that fills the gib- 

 bous base of the tubular corolla is completely shut in by 

 the contorted ovary, which comes into close contact with 

 the inner surface of the corolla-tube above the nectar- 

 cavity. (Plate II. fig. 53, longitudinal section of flower.) 

 In Tricyrtes pilosa (Plate II. fig. 45, longitudinal section 

 of flower) the three outer perianth-leaves have similar 

 gibbosities, full of nectar, at their base ; but above this 

 they are in close contact with the large triangular ovary. 

 Thus the ovary looks like a plug, stuck into the lower 



^ It is worth mentioning here that xery many plants of the Cape 

 flora are characterised by a remarkably abundant secretion of 

 nectar. The flora of any other region might be searched in vain to 

 find such copious nectar as that of Phygelius Capensis, of many 

 Mesembryanthacese and Amaryllidacese, and especially of Melianthus. 

 It is highly probable that this abundant nectar in the Cape flowers 

 is rifled chiefly by honey-birds. 



