328 ANGIOSPERMAE—DICOTYLEDONES 



LXXXIV. ORDER NYCTAGINEAE JUSS. 



740. Oxybaphus L'H^rit. 



2405. O. viscosus L'H^rit. (Heimerl, Verb. Zool.-Bot. Ges., Wien, xxxviii, 

 1888.) — Heimerl describes three stages of anthesis in this species: (i) The stigma 

 is receptive. (2) The anthers dehisce, and self-pollination becomes possible. (3) The 

 anthers, still covered with pollen, brush the stigma. 



741. Mirabilis Riv. 



2406. M. Jalapa L. (Heimerl, op. cit.; Kerner, ' Nat. Hist. PI.,' Eng. Ed. i, 

 II, pp. 212 and 357.) — Heimerl describes the mechanism of this species as agreeing 

 with that of the preceding one. Kerner says that the flowers open between 7-8 p.m. 

 The stigma is then receptive, while the anthers do not dehisce until 10—15 minutes 

 later : there is thus only a very short time between the two stages. Autogamy finally 

 takes place in this night flower, by the rolling up of the filaments and style; the 

 perianth, now becoming pulpy, forms a kind of cork over the tangle constituted by 

 the thread-like filaments and the style. 



Visitors. — Junger noticed especially the hawk-moth Sphinx convolvuli Z. 

 (Herm. MuUer, ' Weit. Beob.,' II, p. 223.) 



742. Acleisanthes A. Gray. 



2407. A. longiflora A. Gray (= Mirabilis longiflora Z.). — Heimerl says that 

 the flowers of this species are probably adapted for pollination by nocturnal hawk- 

 moths. Sprengel (' Entd. Geh.,' p. 121) concluded from the nectar-guides that they 

 were day flowers, but this is doubtful, on account of the fragrance perceptible at 

 night. 



2408. A. Wrightii A. Gray. (Heimerl, op. cit.) — This species bears cleisto- 

 gamous flowers. 



743. Ambronia L. 



2409. A. umbellata Lam. (Heimerl, op. cit.) — Flowers of this species are 

 capable of self-fertilization. 



744. Allionia Loefl. 



Kerner states ('Nat. Hist. PI.,' Eng. Ed. i, II, p. 304) that in species of this 

 genus the stigma is situated at first at the end of the outstretched projecting style in 

 front of the anthers, so that an insect visitor must first brush against it. Later on the 

 style bends to the side at an angle of 80-90°, removing the stigma from the line of 

 approach to the nectar, and thus enabling the visitor to touch the anthers. 



2410. A. violacea L. (= Oxybaphus violaceus Choisy). (Kerner, op. cit., II, 

 p. 357.) — The flowers of this species are protogynous, and autogamy occurs after 

 a few hours by the rolling up of the filaments and style. 



