SCROPHULARINEAE i6i 



(2) Shortly bell-shaped, widely opened, brownish flowers (Scrophularia), with 

 abundant easily visible nectar, in which stigma and stamens mature in succession, 

 and are touched by insect visitors from below. These are chiefly wasps. 



(3) Flowers with a long corolla-tube, open (Digitalis) or closed (Antirrhinum, 

 Linaria), into which visitors introduce themselves entirely or largely, and touch the 

 stamens and stigma with their upper-side. The pollinators are the larger bees. 



(4) Flowers with a narrow corolla-tube (Tozzia, Euphrasia, Rhinanthus, 

 Melampyrum, Pedicularis), with an upper lip sheltering the anthers, and a lower 

 lip serving as a platform for insect visitors, which are dusted with the smooth 

 powdery pollen. The forms with the shortest corolla -tubes are pollinated by 

 flies ; those with tubes of medium length by bees and flies ; and those with long 

 tubes almost exclusively by humble-bees. 



In all species the stigma is first touched by insect visitors, so that cross- 

 pollination is ensured, and this is rendered certain by dichogamy in many cases. 

 Automatic self-pollination often takes place should insect-visits fail. In some 

 species insect-visits and consequent crossing are so perfectly provided for that 

 autogamy does not take place. 



640. Verbascum Toum. 



Partly pollen flowers, partly flowers with nectar, sparingly secreted in small 

 drops on the inner sides of the petals. 



In my opinion the hairs on the filaments serve to increase the conspicuousness 

 of the flowers, at least when their colour differs from that of the petals. But, as 

 Delpino points out, that they also act as holdfasts for insects climbing over the 

 flowers. Kerner says they are devoured by insect visitors, and Hermann MuUer 

 that they are licked by these. 



In many cases conspicuousness is enhanced by the different colour of the 

 anthers. But this end is chiefly brought about by aggregation of the flowers into 

 elongated inflorescences. 



2045. V. thapsiforme Schrad. (Herm. Muller, ' Alpenblumen,' p. 267; 

 Kirchner, 'Flora v. Stuttgart,' p. 575; Schulz, 'Beitrage'; Maury, Bull. soc. bot., 

 Paris, xxxiii, 1886, pp. 529-36; Knuth, ' Bloemenbiol. Bijdragen'; Warnstorf, Verh. 

 bot. Ver., Berlin, xxxviii, 1896.) The golden-yellow flowers of this species are 

 ^gg^'^gated into elongated inflorescences, and are devoid of nectar and nectar- 

 guides. They vary from feebly protogynous to homogamous. The corolla remains 

 expanded even during rain, and its diameter is about 40 mm. Its lowest lobe serves 

 as an alighting platform, is larger than the four others, depressed in the middle, and 

 about 20 mm. broad. The three upper stamens are beset with white hairs and 

 somewhat bent upwards: the two lower ones project about 4 mm, more out of 

 the flower, and their anthers dehisce longitudinally on the side turned towards 

 the style. The flowers are nearly vertical, and the style is beneath all the five 

 stamens. Its end is somewhat bent upwards, and the stigma projects about 4 mm. 

 beyond the two lower stamens, so that it is first touched by the larger insect 

 visitors, and cross-pollination necessarily results. This is also favoured by feeble 

 protogyny, and Kirchner asserts that automatic self-pollination never takes place. 



