SOLANACEAE 



159 



Cross-pollination by insects is only favoured in the feebly protogynous flowers, 

 or in homogamous ones when the stigma projects beyond the anthers. Automatic 

 self-pollination is easily possible and generally inevitable. Kerner found that 

 autogamy was eifected, as in Hyoscyamus, by elongation of the corolla for 

 almost ^ cm. 



Visitors. In the Kiel Botanic Garden I observed (29. 8. '96) the hawk-moth 

 Macroglossa stellatarum L., skg. Also, in the Garden of the Kiel Ober-Realschule, 

 several honey-bees creeping into the flowers and remaining there for some seconds, 

 so that they probably were able to suck some nectar, and might have effected 

 cross-pollination. 



2040. N. rustica L. (Sprengel, 'Entd. Geh.,' p, 125; Kirchner, 'Flora v. 

 Stuttgart,' p. 573; Focke, Kosmos, Leipzig, vi, 1879-80, p. 473; Comes, 'Ult. 

 stud.') The corolla of this species is yellowish-green with a short tube. The 

 filaments bend over the ovary to the style, but diverge from it higher up. Their 

 lower parts are clothed with soft hairs, which protect the nectar from rain, and 

 leave only five narrow passages to it. Comes describes the species as self-fertile. 



Focke observed that humble-bees visited the hybrid N. rustica x N. paniculata, 

 stealing the nectar by perforating the corolla, but they took no notice of the parent 

 species N. rustica. 



636. Physochlaina G. Don. 



2041. P. orientalis G. Don. (Loew, ' Bliitenbiol. Beitrage,' II, pp. 50-2.) 

 The dull-violet net-veined corolla of this species is a gradually widening tube of 

 1 8-20 mm. long, 4 mm. broad below, and 12 mm. above. The anthers protrude 

 from its throat, and the style projects 6 mm. beyond them. Nectar is secreted by 

 a swelling at the base of the ovary. The length of the style and the marked 

 protogyny ensure crossing by insect visitors. 



Visitors. Loew (Berlin Botanic Garden) observed 2 bees, po-cltg. Apis 

 mellifica Z. 5, and Halictus cylindricus F. 9. 



637. Datura L. 



Homogamous moth flowers ; with 

 nectar secreted by the base of the ovary, 

 and concealed between the roots of the 

 filaments. 



2042. D, Stramonium L. 



(Sprengel, ' Entd. Geh.,' pp. 122-3; 



Schulz, 'Beitrage,' I, pp. 73-4; Ker- Fig. 285. Datura stramonium, L. (from nature). 



ner ' Nat Hist PI ' Fne* Fd T TT Flower partly dissected from the side, and somewhat 

 ' ' ' ') & > J reduced. 



pp. 212-13; Warnstorf,Verh. bot.Ver., 



Berlin, xxxviii, 1896; Kirchner, ' Flora v. Stuttgart,' pp. 571-2; Knuth, 'Bloemen- 

 biol. Bijdragen.') Kerner states that the flowers of this species close periodically, 

 and open between 7 and 8 p.m. According to Kirchner, anthesis lasts for 

 only one day. The flowers possess a well-marked, disagreeable musky odour, 

 and when they are freshly opened this is stronger in the evening than 



