298 ANGIOSPERMAE DICOTYLEDON ES 



length. The lowest of these altered flowers still retain the five calyx-teeth, but all the 

 other parts have become aborted. The higher the flowers on the inflorescence, the 

 feebler are the calyx-teeth ; the uppermost flowers are only represented by thick 

 skittle-shaped stalks, somewhat curved, and without a trace of leaves. 



The observations of L. Glaab confirm those of Warming, and were made inde- 

 pendently. In its first stage the capitulum possesses 3-5 fully formed corollas. 

 While these are fading, the axis of the inflorescence turns downwards, and elongates 

 till at last it reaches the ground, into which it presses the fruits till they sometimes 

 appear half-buried in the soiL Those heads which are more or less surrounded by 

 earth produce the greatest number of fruits and vestigial flowers, as well as the most 

 numerous (3-4) and largest seeds ; while those which encounter obstacles, e. g. 

 stones, are relatively retarded in their development. 



705. T. pannonicum L. 



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

 1. Andrena dorsata K. $, po-cltg. ; 2. Anthophora parietina F. & skg., 5 skg. 



and po-cltg. ; 3. Bombus hortorum Z. , skg. ; 4. Megachile centuncularis L. 5, 

 skg. and po-cltg. 



208. Anthyllis L. 



Yellow nectar-producing bee flowers with a pumping arrangement, extruding 

 threads of pollen. The tips of all ten filaments are clavate. 



706. A. Vulneraria L. (Delpino, 'Ult. oss.,' p. 45; Herm. Muller, 'Fertili- 

 sation,' pp. 172-3, ' Alpenblumen,' pp. 248-9; Knuth, 'Bl. u. Insekt. a. d. nordfr. 

 Ins.,' pp. 58, 152 ; Kerner, ' Nat. Hist PI.,' Eng. Ed. 1, II ; Frey, ' Lepidopteren der 

 Schweiz,' pp. 16, 20; Schulz, 'Beitrage,' II, p. 208.) The flower mechanism of 

 this species was first described by Delpino, and afterwards more fully by Hermann 

 Muller, who gives the following account of it. The greatly elongated claws of the 

 petals are enclosed by a calyx 9-10 mm. long, and somewhat dilated in the middle. 

 From this the vexillum, which is expanded and flat at the end, projects as much as 

 6-7 mm. It extends somewhat beyond the alae, embracing these above with the 

 grooved base of its limb, while at the same time it grasps and almost completely 

 enfolds them from below by means of two rounded lobes, one on either side of its 

 base. The alae ensheath the carina, with which they are so closely united that it 

 is depressed along with them during insect-visits. The union of these parts is 

 effected in three ways: (1) A narrow, deep groove on the upper side of each ala, 

 near its base, fits into a fold of the carina below it. (2) A pointed triangular tooth, 

 projecting from the outside of this carinal fold fits into the space behind the alar 

 groove. (3) Two internal folds, one from the upper margin of each ala, fairly far 

 forwards, hold these petals firmly together above the carina. The tip of the carina 

 projects immediately in front of these folds, and opens by a slit when the alae are 

 depressed. Behind this slit the upper edges of the carinal petals are fused. The 

 pressure of a bee visiting the flower squeezes out a string of pollen from the slit, 

 pushed from behind by the thickened ends of the ten stamens. The pollen is 

 stored up in the tip of the carina while the flower is still unopened. When the 

 pressure on the alae and carina is removed, these return to their former position, 

 and when the pressure is renewed fresh pollen masses are extruded. At a later 





