i6o ANGIOSPERMAE—DICOTYLEDONES 



during the day. They close in dull weather by folding the funnel-shaped 

 corolla. As night flowers they possess no nectar-guides, and are generally quite 

 white in colour, sometimes with a reddish or bluish tinge. The corolla-tube is 

 55 to 65 mm. long, and broadens out into a limb. The lower parts of the 

 filaments are fused with the corolla-tube by their narrow posterior edges, and 

 their anterior margins are broadened out in such a way that their edges touch. 

 In this way are bounded five long tubular nectar-passages. (' Revolver flowers.') 

 The inner sides of the filaments are beset with short upwardly directed hairs. 

 Stigma and anthers are at about the same level. As the flowers are tolerably 

 upright, automatic self-pollination can take place if insect-visits fail, and when the 

 corolla closes this is inevitable. Schulz states, however, that the stigma sometimes 

 projects beyond the anthers. He was unable to detect nectar in the flowers. 



Warnstorf describes the pollen-grains as white in colour, of irregular rounded 

 polyhedral shape, and on an average 56 /x in diameter. 



Visitors. — I observed only the beetle Meligethes, freq. 



638. Nierembergia Ruiz et Pav. 



2043. N. linariaefolia R. Grab. (=N. filicaulis Li7idl.). (Francke, Inaug.- 

 Dissert., Halle, 1883.) — Francke describes this species as protogynous. The 

 anthers roof over the stigma. 



639. Saracha Ruiz et Pav. 



2044. S. viscosa Link. (Francke, Inaug.-Dissert., Halle, 1883.) — Francke 

 describes this species as protogynous, but autogamy is ultimately possible. 



LXXIV. ORDER SCROPHULARINEAE R. BR. 



Literature. — Herm. Miiller, 'Fertilisation,' pp. 429-65, ' Alpenblumen,' 

 pp. 303-7 ; Knuth, ' Grundriss d. Blutenbiol.,' p. 79 ; R. von Wettstein, ' Scrophula- 

 riaceae,' in Engler and Prantl's ' D. nat. Pflanzenfam.,' IV, 3 b, pp. 46-7. 



In this corner the brightly coloured corolla makes the flowers conspicuous, and 

 this is enhanced by their aggregation into racemose inflorescences. Yellow and red 

 predominate, while many tropical species are scarlet. Variations of colour are found 

 in some instances, most strikingly in Linaria. The flowers of L. virgata Desf., for 

 example, are generally purple, and those of L. reflexa Desf. yellow, but in the 

 mountains these are white (Wettstein). Most species of Verbascum bear pollen 

 flowers, in those of the remaining genera nectar is secreted at the base of the 

 ovary, or in Pentstemon at the bases of the filaments. With reference to 

 concealment of nectar the following flower classes are represented in the order. — 

 C (Veronica) ; H (Digitalis, Linaria, Euphrasia, Rhinanthus, Melampyrum, Bartsia, 

 Pedicularis) ; L (Rhinanthus alpinus KocK) ; F (Tozzia alpina Z.). 



Hermann Miiller distinguishes the following four groups. — 



(r) Short-tubed open flowers (Verbascum, Veronica), with freely projecting 

 stamens and pistil, which insect visitors usually touch at random. The stigma 

 generally matures, however, before the anthers. The pollinators are bees and flies. 



