LABIATAE 283 



South Tyrol and purplish-white in Lower Austria and Hungary; near Zurich, 

 however (according to Stadler), they are reddish or white with purple nectar-guides 

 on the lower lip. They are very fragrant and markedly protandrous, self-pollination 

 being therefore generally excluded. During dehiscence of the anthers, which are 

 situated in the upper part of the entrance of the flower and dehisce downwards, the 

 style is so short that the still immature stigma lies between the anthers of the short 

 stamens or slightly higher. As a rule it is only after dehiscence, or towards the end 

 of it, that the style elongates and curves slightly downwards in such a way that the 

 now mature stigma is brought under the anthers of the longer stamens or a little in 

 front of them. Bonnier asserts that this species possesses a reduced nectary, but 

 Schulz considers this view ill-founded. The latter describes the nectary as a slightly 

 C3'lindrical swelling under the ovary, rarely thickened in front, and secreting nectar so 

 very abundantly that the corolla-tube (25-35 ™n^- long) is filled with it to a height 

 of 7-10 mm. Stadler also found the nectary to be much more strongly developed 

 in front than elsewhere. There is a thick growth of hair serving as a nectar-cover. 

 As the corolla-tube is narrowed by two longitudinal folds, to which the filaments are 

 united, two narrow entrances are formed (and three in the mouth of the flower), 

 situated one above the other. Kerner describes this as characteristic of ' revolver 

 flowers ' (cf. e. g. Gentiana, p. 100, and Convolvulus, p. 143). 



Visitors. — These are humble-bees and hawk-moths. Hermann Miiller, junior, 

 observed Bombus hortorum L. Schulz says that long-tongued humble-bees need not 

 penetrate very far into the corolla to reach the nectar ; the short-tongued ones, on 

 the contrary, are obliged to probe very deeply, and even then do not quite reach the 

 bottom of it on account of the length of the corolla-tube. The white-flowered 

 variety albida Guss. seems specially adapted for fertilization by hawk-moths. Schulz 

 caught Deilephila euphorbiae Z., D. elpenor Z., and Sphinx convolvuH Z. at Bozen. 

 He also observed larger moths (Noctuids and Bombycids?), but was unable to 

 capture them. Beetles, flies, small hymenoptera and physopods occurred as useless 

 visitors. Schulz occasionally found the flowers perforated at the base. Stadler 

 observed Bombus terrester Z. as a nectar-thief. 



722. Lamium L. 



Red or white homogamous humble-bee or bee flowers ; with nectar secreted by 

 the fleshy base of the ovary, which is generally more strongly developed below, and 

 stored at the bottom of the corolla-tube. There is usually a nectar cover in the form 

 of a circle of hairs above the secretion. The galeate upper lip shelters the anthers, 

 and the lower lip forms a convenient alighting-platform for visitors. Schulz says that 

 the stamens of almost all the German species are now and then reduced. Sometimes 

 cleistogamy. 



2312. L. album L. (Sprengel, 'Entd. Geh.,' pp. 302-4; Herm. Miiller, 

 'Fertilisation,' pp. 493-5, ' Alpenblumen,' p. 311, ' Weit. Beob.,' HI, p. 64; Schulz, 

 'Beitrage,' II, p. 221 ; Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' p. 117; MacLeod, 

 Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 369; Kirchner, ' Flora v. Stuttgart,' p. 621 ; 

 Loew, ' Blutenbiol. Floristik,' pp. 391, 399.) — In the flowers of this species the white 

 (rarely pinkish) corolla possesses a pale yellow lower lip marked with olive-green 



