LABIATAE 309 



2368. S. alpina L. (MacLeod, < Pyreneenbl.,' pp. 58-61.) The flower 

 mechanism of this species agrees essentially with that of S. galericulata. Here again 

 the upper Hp can be bent back on a hinge-joint. When the pressure of the insect 

 visitor is removed, the lip resumes its original position and encloses stigma and 

 anthers. The narrow upper opening of the tip of the upper lip again forms a 

 Lepidopterid door. A humble-bee can insert its head 5-6 mm. deep in the upper 

 and widened part of the corolla-tube, and it is then only 10-12 mm. from the nectar- 

 bearing base of the flower. The nectary is situated on the front side of the base of 

 the ovary. 



The flowers are blue-violet in the Alps, and the orange-coloured nectar-guide on 

 the swelling of the lower lip is larger than that of the darker flowers in the Pyrenees. 

 Visitors. MacLeod observed a humble-bee, apparently Bombus hortorum Z. 5. 



2369. S. peregrina L. 



Visitors. Loew (Berlin Botanic Garden) observed the humble-bee Bombus 

 hortorum Z. ^, its head thickly covered with pollen. 



2370. S. albida L. 



Visitors. Loew observed the following in the Berlin Botanic Garden. 

 Hymenoptera. {a) Apidae: allskg. : i. Bombus cognatus 6"/^/^. 5 ; 2. B. 



terrester Z. 5 ; 3. Osmia aenea Z. 5. {b) Tenthredinidae : 4. Athalia rosae Z., 



settling on the outside of the flowers. 



2371. S. altissima L. 



Visitors. Loew (BerHn Botanic Garden) observed the bee Chelostoma 

 nigricorne Nyl. j, creeping right into the flowers and skg. 



733. Prunella L. 



Protandrous or homogamous bee flowers ; with nectar secreted and concealed 

 as usual. Sometimes gynomonoecism or gynodioecism. 



2372. P. vulgaris L. (Sprengel, 'Entd. Geh.,' p. 312; Herm. Miiller, 

 'Fertilisation,' pp. 489-91, * Alpenblumen,' p. 315, *Weit. Beob.,' Ill, pp. 51-2; 

 Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896; MacLeod, Bot. Centralbl., Cassel, 

 xxix, 1887, Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 377-8; Kirchner, 'Neue 

 Beob.,' p. 58, ' Flora v. Stuttgart,' p. 635 ; Knuth, ' Blutenbiol. Beob. a. d. nordfr. 

 Ins,,' pp. 118, 166, ' Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,* p. 239; Ogle, 

 Pop. Sci. Rev., London, ix, 1870; Schulz, 'Beitrage,' I, p. 85; Loew, 'Blutenbiol. 

 Floristik,' p. 394.) The flowers of this species are violet in colour. The corolla- 

 tube of the large-flowered hermaphrodites is 7-8 mm. long. The anthers are situated 

 in two rows, one behind the other, below the upper lip. The longer filaments possess 

 a sharp tooth below the anthers, directed outwards, its free end resting against the 

 arched surface of the upper lip. Ogle and Hermann Miiller consider that this is an 

 arrangement for keeping the downwardly dehiscing anthers at the side of the median 

 stigmatic branches, a position in which they are most exposed to contact with visitors. 

 Each of the shorter filaments possesses a similar tooth, serving the same purpose, but 

 much less developed. The flowers are partly homogamous, and partly, according to 

 Schulz, feebly or strongly protandrous. The back of a humble-bee first touches the 

 papillae of the projecting lower stigmatic branch, and then becomes dusted with pollen. 



