290 



ANGIOSPERMAE—DICOTYLEDONES 



cm. in diameter at the top, and about 2^ cm. 



oblique funnel, 2^3 cm. long, 2-2 



deep. Its margin is beset with five small spines. The other parts of the flower are 



thus well protected from rain, injurious insects, and perforating nectar-thieves. 



The arched upper lip, slightly cleft in the middle, is pale pink outside, and 

 brighter pink inside ; its length is about the same as that of the longer stamens, so 

 that only the extreme tips of the anthers of these project beyond it. The lower lip 

 is of considerable length (12-13 mm.), and lies on the lower, inner surface of the 

 calyx, which provides the necessary foothold for insect visitors. The large yellowish- 

 white central lobe of the lower lip is rather deeply cleft, and provided with a longi- 

 tudinal median groove, which is prolonged into the nectar-bearing base of the flower. 

 The lateral lobes are small and triangular. Both lips are marked internally with dark 

 rose-coloured nectar-guides. 



The corolla-tube is 8 mm. long, so that only long-tongued humble-bees can 

 suck all the nectar secreted by the base of the ovary. It is further protected by 



F^G. 335. Molitcella laevis, L. (from nature). (i) Flower seen from the front. (2) Do., from the 

 side, after removal from the calyx. {Natural size.) (3) Tips of the reproductive organs, from the side : 



a and a\ anthers of the shorter and longer stamens ; j, stigma (x 3). {4) The pistil : «, nectary ( x 2J). 



a gibbosity 3 mm. from the bottom of the corolla-tube, from which a fold of membrane 

 runs inwards to serve as a nectar-cover. 



The flowers are homogamous. The stigma is situated between the anthers of 

 the two longer stamens, frequently projecting far beyond them, and the two stigmatic 

 branches curve away from each other above and below. The lower branch is first 

 touched by an insect visitor and dusted with foreign pollen, the upper side of the 

 proboscis or the head of the visitor being then sprinkled with fresh pollen. Should 

 insect-visits fail, automatic self-pollination by the longer stamens is effected. 



Visitors. — Knuth (Kiel Botanic Garden, 26. 8. '97) observed 2 humble-bees 

 with proboscis long enough to suck all the nectar — Bombus agrorum F. S (prob. 

 lo-ii mm.), and B. lapidarius Z. S (prob. 8-10 mm.). 



724. Galeopsis L. 



Homogamous, rarely feebly protandrous bee flowers. The galeate upper lip 

 serves as a protecting roof for the anthers in bad weather, while the lower lip forms 

 a platform and possesses two lateral, hollow teeth which guide the head of a bee 

 visitor. As usual the base of the ovary serves as a nectary, which broadens consider- 



