284 



ANGIOSPERMAE—DICOTYLEDONES 



dots. The nectary, which is situated below the ovary, broadens out below into 

 a fleshy lobe surrounding the lower half of the anterior part of the ovary. Nectar 

 collects in the lowest, narrowest part of the corolla-tube, which is 10 mm. long, and 

 is covered by a dense circlet of hairs. Above this the corolla-tube suddenly widens 

 out, and instead of running obliquely becomes vertical. On account of the length of 

 the corolla-tube the nectar is only accessible to long-tongued humble-bees and bees. 

 These touch first the lower stigmatic branch and then the anthers, which mature 

 simultaneously. One of the stigmatic branches continues the direction as the 

 style, and lies therefore between or above the anthers; the other bends down 

 between them in the middle, so that its tip projects below the anthers and is therefore 

 first touched by hymenopterous visitors. If insect-visits fail, automatic self-pollination 

 takes place in consequence of the simultaneous maturation and relative position of 

 stigma and anthers ; this method is, however, seldom made use of, on account of the 



frequency of insect-visits. Warn- 

 storf describes the pollen-grains 

 as pale yellow in colour, ellipsoidal, 

 delicately tuberculate, 41 /x long 

 and 27 /i wide. 



Visitors. — These are long- 

 tongued hymenoptera, particu- 

 larly humble-bees : the visitor's 

 head is conveniently inserted 

 between two upright lobes lying 

 between the corolla-tube and the 

 lower lip, and continuing its side 

 walls. While sucking the bee 

 clings to the base of the lower lip 

 with its forelegs, and with its 

 middle and hind ones to the two lobes of this lip, so that a proboscis of not less than 

 10 mm. long can reach the nectar-bearing base of the flower. Meanwhile the thorax, 

 and in the case of smaller workers the base of the abdomen also, fill up the space 

 between upper and lower lips so accurately that the former closely surrounds the 

 upper side of the visitor, and the stigma and anthers are pressed tightly against 

 its back. 



Humble-bees with proboscides too short to reach the nectar (e. g. Bombus 

 terrester L.) perforate the corolla-tube and steal it. Short-tongued bees (including 

 the honey-bee) suck nectar through the holes made by B. terrester. 



Visitors. — Herm. Miiller gives the following list. — 



A. Diptera. Syrphidae: i. Rhingia rostrata L., skg. and po-dvg. B. Hy- 

 menoptera. Apidae: 2. Andrena albicans TJ/i//. 5, po-cltg. ; 3. K. n\i\d,a. Fourc. ^, 

 skg. through holes made by Bombus terrester; 4. Anthidium manicatum L. 5 

 and S, skg. (Strasburg) ; 5. Anthophora personata III. 5 and S, do. (Strasburg) ; 

 6. A. pilipes F. } and $, do.; 7. Apis mellifica L. $, skg. through holes made by 

 Bombus terrester ; 8. Bombus agrorum F. 5 and 5, skg. and transferring pollen 

 from the upper side to its baskets; 9. B. hortorum L. 5 and 5, do.; 10. B. lapi- 

 darius L. 5 and j, do.; 11. B. muscorum F. 5, as B. agrorum; 12. B. pratorum 



Fig. 334. Lamiufn album, L. (after Hcrrn. Miiller). 

 (1) Flower seen from the side. (j) Du., after removal of the 

 calyx. (3) Ovary and nectary (X 7). (4) End of the style 

 ( X 7). a, nectary \ b, lower lip ; c, lateral lobes, between which 

 the heads of humble-bees are pushed; d^ useless appendages: 

 e, upper lip (sheltering; rool) ; _/, stamens ; ^, lower stigmatic 

 branch. 



