348 



HUTCHINSON'S POPULAR BOTANY 



FIG. 427. COLUMBINE (Aquilegia 



vulgaris), 

 With each of the five petals ending in a spur. 



honey. This nectary is presented 

 to the humble-bee just like a spoon 

 as it sits on the lower lip. Directly 

 the bee goes, the lower lip snaps 

 to, and the nectary disappears from 

 view." The Calceolarias, indeed, 

 bring before us a new form of 

 corolla, the calceolate, or slipper- 

 shaped. They offer good illustra- 

 tions of special thickenings in 

 parts of flowers where the strain 

 caused by insects is most felt. 

 Calceolaria pavonii is a striking 

 example of this. Along each of 

 the upper edges of the curved 

 basal part of this flower that part 

 which carries the inflated end upon 



which the bee stands there is a thickened ridge, and this gives wonderful 

 strength to the support and prevents injury when the bee alights. 



The very cohesion of the petals, in this as in all flowers where cohesion 



takes place, is also a source of 

 strength ; and swellings and hollow 

 projections in particular places may 

 subserve a" similar end. The bulge 

 in the tubular part of the Foxglove 

 flower is evidently for this purpose ; 

 as in all probability are the curious 

 projections in many kinds of gibbous 

 or pouched corollas. The Great 

 Wild Valerian ( Valeriana officinalis, 

 fig. 418) offers a good example of 

 this form. The small pouch or 

 hump in this particular flower is 

 the nectary, in the green fleshy 

 floor of which the honey is secreted. 

 As the pouch is short and easily 

 accessible, the flower is largely 

 patronized by insects, and cross- 



mm 



FIG. 428. PAPILIONACEOUS COROLLA, 



With the parts separated, (v) Vexillum or standard 

 (a) Alee or wings, (c) Carina or keel. 



pollination regularly takes place. 



Returning for a moment to the 

 simpler kinds of gamopetalous 

 flowers, notice a familiar example 

 of the globose corolla (fig. 430). It is 

 the Fig wort (Scrophularia nodosa], 



