IRIDEAE 425 



4. Podalirius acervorumZ.; 5. P. retusus Z., var. meridionalis Per.; 6. Xylocopa 

 violacea Z. 



855. Gladiolus L. 



Protandrous humble-bee flowers. Treviranus says that autogamy finally take 

 place by the bending back of the style. 



2672. G. segetum Ker-Gawl. (Delpino, ' Ult. oss.,' p. 384 ; Kerner, ' Nat. 

 Hist. PI.,' Eng. Ed. i, II, pp. 279, 282, 297; Loew, ' Bliitenbiol. Floristik,' 

 pp. 347-8; Grassmann, ' D. Septaldrusen ' ; Urban, Ber. D. bot. Ges., Berlin, iii, 

 1885; K. F. Jordan, Inaug.-Diss., Halle, 1886.) — The purple-red flowers of this 

 species possess, like those of the following one, a nectar-guide on the three lower 

 perianth lobes in the form of white streaks edged with purple-red. The flower is 

 35-45 mm. long. Loew says that the perianth lobes split a little at the edges, and 

 project more on the lower side than on the upper. The slightly bent flowers, with 

 perianth tube about 10 mm. long and 3 mm. broad, are adapted by form and size for 

 pollination by humble-bees, which find them conveniently large. In flowers in the 

 first stage of anthesis, these visitors brush off the pollen from the anthers situated 

 below the roof-shaped upper perianth lobes with their backs, and transfer it to 

 flowers in which the stigmas have been brought into the line of access by elongation 

 of the style ; these are membranous, strongly papillose, and expanded downwards 

 and forwards. Grassmann describes the accesses to the nectar secreted by the ovary 

 as being right and left openings bounded by the filaments. Jordan says that the two 

 lateral stamens twist round their pollen-covered sides towards these two openings. 

 The anterior stamen is also at first turned outwards, but later on bends over back- 

 wards, so that the style is pressed against the posterior perianth lobe. Urban has 

 given detailed descriptions of the latter torsion of the flowers, and the relation of their 

 position to insect-visits. 



Besides hermaphrodite flowers, Delpino observed purely female ones. 

 Visitors. — Loew (Berlin Botanic Garden) observed humble-bees, skg. normally 

 and effecting pollinations ; also smaller bees (Apis, Andrena sp.) as useless guests. 



2673. ^- triphyllos Sibth. et Sm. — 



Visitors. — Loew (Berlin Botanic Gardens) observed the honey-bee, vainly skg. 



2674. G. Gandavensis Van Houtte (= G. cardinalis Curl., and G. psittacinus 

 Hook.). — This hybrid is pollinated by long-tongued humble-bees, which remove 

 pollen on their backs and transfer it to the stigma (Magoscsy-Dietz, 'A novenbiologia 

 KoreboU '). 



2675. G. palustris Gaud. (Herm. Miiller, 'Weit. Beob.,' I, p. 283; Knuth, 

 ' Bloemenbiol. Bijdragen.')— This species possesses the same flower mechanism as 

 G. segetum. 



Visitors. — Borgstette (Tecklenburg) and Knuth (Gardens at Kiel) observed the 

 humble-bee Bombus hortorum Z. 5, skg. 



2676. G. communis L. (Herm. Miiller, loc. cit.) — 



Visitors. — Buddeberg (Nassau) observed 2 bees(Osmia rufaZ. 5, and O. adunca 

 Ltr. S, skg.), and Schletterer (Tyrol), 2 bees (Bombus argillaceus Scop., and 

 Xylocopa violacea Z.). 



