SOLANACEAE 



'55 



628. Nicandra Adans. 



Flowers wiih concealed nectar, secreted by the base of the ovary. 



2029. N. physaloides Gaertn. (Sprengel, 'Entd. Geh.,' p. 126; Kerner, 

 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 217.) — The whitish bell-shaped flowers of this 

 species possess a bright-blue corolla-limb. Kerner says they open about 11-12 

 in the morning, closing again about 3-4 p. m. The filaments bend into a 

 semicircular curve, bringing the anthers into contact with the stigma and thus 

 automatically effecting self-pollination. The stigma withers and turns brown an 

 hour after it is pollinated, the style falls off at the same time, and the corolla 

 fades. Sprengel states that the bases of the anthers are thickly clothed with hairs 

 serving as nectar-covers. The nectar-guides are in the form of five dark-blue 

 blotches at the base of the corolla, alternating with the filaments and situated 

 immediately above the nectar-covers. 



Visitors. — In the Garden of the Kiel Ober-Realschule I saw (10. 9. '97) 

 honey-bees which crawled completely into the flowers to suck the nectar, and 

 effected cross-pollination. 



629. Atropa L. 



Protogynous humble-bee flowers; with nectar secreted at the base of the 

 ovary, and concealed in the lowest contracted part of the bell-shaped corolla. 



2030. A. Belladonna L. (Herm. Miiller, ' Weit. Bcob.,' Ill, pp. 24-6 ; 

 Kirchner, ' Flora v. Stuttgart,' pp. 569-70 ; Knuth, ' Bloemenbiol. Bijdragen ' ; 

 Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 305.) — In 



this species the limb and ventricose part of the corolla 

 are coloured dirty-brown red, and its lower part dirty 

 yellow-green. The measurements of the beO correspond 

 in size and shape to a medium-sized humble-bee. The 

 flowers are directed obliquely downwards, horizontally, 

 or it may be upwards, so that their interior is not always 

 protected from rain. Small unbidden insect guests are 

 kept away from the nectar by strong erect hairs which 

 cover each filament for a length of 4 mm. At the same 

 level as the uppermost part of this barrier the corolla 

 is thickly lined by small stiff erect hairs. 



The stigma projects considerably beyond the stamens, 

 and is mature at the beginning of anthesis, while its position 

 is such that humble-bees creeping into the flower must at 

 once touch it, for the style is slightly bent downwards, and 

 its stigma-bearing end turns slightly upwards. The an- 

 thers are at this stage still closed. They lie within the corolla-tube, for the filaments 

 are curved inwards. Later on they dehisce and become covered all over with pollen, 

 while at the same time the filaments straighten to some extent. But they remain 

 more or less curved inwards, so that the stigma continues to project beyond them, 

 and is first touched by insect visitors. Cross-pollination is thus ensured. 



As the style with its stigma lies in the lower part of the bell, the latter is 



Fig. 28,v Atropa Belladonna, 

 L. (from nature). Flower after re- 

 moval of half the calyx and corolla, 

 fl, anthers; n, nectary; j, stigma. 



