154 ANGIOSPERMAE—DICOTYLEDONES 



times even to only such of these as possess a very long proboscis (hawk-moths). 

 The flowers therefore belong to class L. Many species are gynomonoecious or 

 gynodioecious. 



381. D. deltoides L. (Herm. Muller, 'Fertilisation,' pp. 125-6, ' Weit. Beob.,' 

 II, p. 230; Kirchner, 'Flora v. Stuttgart,' p. 244; Knuth, 'Bloemenbiol. Bij- 

 dragen.') — This species bears protandrous butterfly flowers. Hermann Muller 

 (op. cit., p. 125) says that — 'The stamens and petals spring from an annular ridge 

 of the receptacle encircling the stalk of the ovary. This ridge bears on its inner 

 border a yellow fleshy cushion which secretes honey.' As the calyx tube is 12- 

 14 mm. long, the passage to the nectar is of the same length, while it is only 

 2 mm. in diameter. At the beginning of anthesis this passage is made so narrow- 

 by the live inner stamens it encloses as to leave only enough room for the intro- 

 duction of a butterfly's proboscis. The path to the nectar is indicated by a nectar- 

 guide on the rose-red corolla, of which the whitish centre is surrounded by a 

 purple-red ring with whitish spots. Of the ten stamens, the five outer ones first 

 elongate so that their anthers project from the corolla-tube when they have dehisced. 

 After the outer stamens have withered the other five behave similarly. When all 

 ihe pollen is shed the two styles — which have so far been twisted together within 

 the corolla-tube — elongate, and their stigma-bearing ends project from the flower, 

 dominating its entrance. When the styles separate they remain spirally twisted, 

 so that the proboscis of a butterfly approaching the flower from any side must 

 necessarily touch some of the stigmatic papillae, effecting cross-pollination if the 

 insect has previously visited a younger flower. 



Visitors. — The following were observed by Herm. Muller (H. M.) in Westphalia, 

 and myself (Kn.) in Schleswig-Holstein. — 



Lepidoptera. {a) Bomhycidae: i. Gnophria quadra Z., skg. (?) (H. M.). 

 (/■) Tineidae: 2. Nemotois metallicus /"o^/a (H. IM.). {c) Rhopalocera : 3. Hesperia 

 lineola C, very freq., skg. (H. M.); 4. H. thaumas Hfn., skg. (H. M.); 5. Lycaena 

 icarus Roit., skg. (Kn., H. I\I.) ; 6. Pieris napi Z., skg. (H. M.) ; 7. P. rapae Z., skg. 

 (H. M.); 8. P. sp., skg. (H. M.); 9. Polyommaius phlaeas Z. skg. (Kn.); 10. Rho- 

 docera rhamni Z., skg. (Kn.); 11. Epinephele janira Z. (H. M.). 



I saw in Thuringia, as a useless visitor, the small bee Halictus morio F. }, vainly 

 trying to suck nectar, and afterwards po-cltg. 



Loew noticed the following in Silesia (' Beitrage,' p. 33). — 



A. Diptera. Syrphidae: i. Volucella bombylans Z., trying to suck. B. Lepi- 

 doptera. Rhopalocera : 2. Argynnis pandora S. I'., skg.; 3. Pieris brassicae Z. ; 

 4. Rhodocera rhamni Z., skg. 



382. D. superbus L. (Sprengel, ' Entd. Geh.,' p. 248; Herm. Muller, 'Fer- 

 tilisation,' p. 127, ' Alpenblumen,' pp. 202-4.) — The fragrant protandrous diurnal 

 hawk-moth flowers are red in colour, and elegant in appearance, owing to the 

 delicately dissected petals. Their mechanism agrees with that of the last species, 

 though the nectar is so deeply concealed (20-25 mm.), and the access to it so 

 narrow, that even butterflies cannot reach it, but only the diurnal hawk-moths 

 (species of Macroglossa). Self-pollination is excluded. Besides hermaphrodite 

 flowers, infrequent female ones have been observed, which are smaller than the 



