54 ANGIOSPERMAE—DICOTYLEDONES 



III. ORDER MAGNOLIACEAE DC. 



26. niicium L. 



111. I. religiosum L. — According to Delpino ('Applicaz. d. teor. Darwin ai 

 fiori ed agli insetti visit, d. fiori,' Boll. Soc. Entom., Firenze, ii, 1870, p. 10), there 

 are small juicy glands like stigmatic papillae in the middle of the flower that probably 

 serve to attract beetles (Cetoniae), which while licking nectar effect pollination. 



27. Magnolia L. 



112. M. Yulan Desf. — This species is a native of China. The erect white 

 lily-like blossoms are odorous, and — according to Delpino (' Ult. Oss.,' Atti Soc. ital. 

 sc. nat,, Milano), they are protogynous bee flowers. In the first (female) stage 

 of anthesis, the bees that visit them are not able to climb up the smooth petals, 

 nor to free themselves from the short erect carpels occupying the middle of the 

 flower, and therefore remain prisoners till the second (male) stage, in which the 

 anthers dehisce. They are then able to leave the flower, and being dusted with 

 pollen, may transfer this to the stigmas of another flower which is still in the 

 first stage. 



113. M. grandiflora L. — This species is indigenous to Florida. According 

 to Delpino (op. cit., pp. 233-5), the white odorous protogynous flowers are visited 

 and pollinated by beetles (Cetoniae). During the first stage of anthesis, these insects 

 find under the three inner petals, which arch over the carpels, a warm nectar- 

 containing shelter, that they only leave when the petals are shed at the time 

 of dehiscence of the anthers. Dusted with pollen they then betake themselves 

 to another flower in the first stage, the mature stigmas of which they necessarily 

 pollinate. Self-pollination is prevented by the pronounced protogyny. 



Visitors. — Cetonia aurata L., and Oxythyrea funesta Poda (= C. stictica Z.). 



IV. ORDER ANONACEAE JUSS. 



28. Asimina Adans. 



114. A. triloba Dunal. — Delpino states (op. cit., p. 231) that the stamens 

 project in the centre of the pendulous protogynous flower as a hemispherical mass, 

 from the middle of which a few styles with their stigmas project. In the first 

 (female) stage of anthesis the three inner petals lie so close to the stamens that 

 insect visitors (flies) cannot suck the nectar secreted at the bases of the former 

 without touching the already mature stigmas. In the second (male) stage the 

 stigmas have dried up and the inner petals have raised themselves, so that the 

 anthers — now covered with pollen — are touched by insects on their way to the 

 nectar. Cross-pollination of the younger flowers is therefore efiected by trans- 

 ference from the older ones. 



Visitors. — Delpino observed the following seven Muscidae, which were deter- 

 mined by Rondani. — 



I. Calliphora erythrocephala Mg.; 2. Lucilia sericata Mg.; 3. Cyrtoneura 

 pascuorum Mg.; 4. C. stabulans Fall.; 5. C. assimilis Fall.; 6. Homalomyia 

 prostrata Rossi: 7. Megaglossa umbrarum Mg. 



