356 ANGIOSPERMAE—DICOTYLEDONES 



curved so far outwards and downwards that the stigmas aie isolated in the middle 

 of the flower, and must inevitably be touched by any insect visitors. In the second 

 stage the flower is wide open, the six stamens of the inner whorl erect themselves and 

 stand quite close to the stigmas, each stamen being brought between two of these, 

 and the anthers dehisce extrorsely. Automatic self-pollination may now be easily 

 effected, in consequence of the downwardly directed position of the flower ; the 

 spinose processes of the outer stamens also project beyond the stigmas, so that these 

 are much less likely to be touched by visitors. Finally, the inner stamens erect 

 themselves in succession and become inserted between the outer ones. They are 

 somewhat shorter than the latter, their anthers being therefore situated exactly below 

 the six still receptive stigmas. The mealy pollen falls into the flower in the form 

 of yellow dust. 



Visitors. — In spite of repeated prolonged watching in the Kiel Botanic Garden, 

 Knuth only once observed a carrion-fly (Lucilia caesar Z.), casually alighting. 



2500. A. canadense L. (Delpino, op. cit.) — The flower mechanism of this 

 species agrees with that of the preceding one. 



2501. A. albivenium Kegel (= Heterotropa asaroides Morr. el Becne.). 

 (Delpino, op. cit.) — As regards the construction and mechanism of the flower, 

 this species comes between Arum and Aristolochia. Delpino supposes that the 

 inwardly curved margin of the perianth forms a temporary prison for the visitors, 

 which are probably flies. 



XCI. ORDER L A URINE A E VENT. 

 773. Laurus L. 



2502. L. nobilis L. — 



Visitors. — The following were recorded by the observers, and for the localities 

 stated. — 



Schletterer (Pola), the bee Halictus calceatus Scop., var. obovatus K., and the 

 ichneumon-fly Bassus laetatorius F. Alfken (Bozen), the honey-bee Apis mellifica 

 L. 5, very freq., skg., the wasp Polistes gallicus L. 5 and S, freq., the Sphegid Cerceris 

 quinquefasciatus Rossi, freq., and the hover-fly Helophilus floreus L., very treq., skg. 

 and po-dvg. 



XCII. ORDER PROTEACEAE JUSS. 



Delpino (' Ult. oss.') says that species belonging to this order are protandrous. 

 Self-pollination is undoubtedly excluded, for the pollen is generally removed by 

 insect visitors before the stigmas are mature. Delpino supposes that various kinds 

 of honey-sucking birds are visitors. 



XCIII. ORDER THYMELAEACEAE JUSS. 

 774. Daphne Toum. 



Flowers homogamous, with nectar secreted and concealed in the base of the 

 corolla-tube, and accessible to flies, bees, or Lepidoptera only according to the length 

 of the latter. They thus belong to classes C to L. 



