mentioned table in Kerner's " Pflanzenleljen," and indeed to ob- 

 servations on the period of anthesis as far back as the famous 

 "floral clock" of Linnaeus. In compiling this list no attention 

 seems to have been given to the time which elapsed between the 

 beginning of anthesis and pollination, and no distiction was made 

 between pollinated and unpollinated flowers. Thus for native 

 European species, most of which would be accessible to their nor- 

 mal insect visitors, a short period of anthesis is as a rule recorded, 

 while the exotic orchids are credited with periods of several 

 weeks — 60 da\'s in the case of Oncidium cnientum, 70 for Cypri- 

 pediitm villosiitn, 80 for Odontoglossum Rossii, etc. We know 

 from the work of Fitting* that the corollas of orchids (at least 

 those which do not turn green after fertilization) fall very soon 

 after pollination, and this irrespective of the period which has 

 elapsed since they first came into flower. Hence we may safely 

 assume that the orchids for which Kerner records the long periods 

 had not been pollinated. The problem of how the presence of the 

 pollen affects the corolla, often at a considerable distance, has not 

 been solved. We know from much recent work that stimuli are 

 transmitted through the plant body by means of hormones, which 

 either diffuse through the tissues, or are more rapidly carried in 

 the transpiration stream. However, there is at present no con- 

 clusive evidence that such plant hormones are active in bringing 

 about postfloration changes in flowers, although we may assume 

 this to be the case. 



A morphological peculiarity worthy of notice in H. Moscheutos 

 and some allied species is the elevation of the leaf-like bracts 

 upon the pedicels which are axillary to them. In other words, 

 the leaf, which is normally situated upon the main stem, and 

 from the axil of which the pedicel springs, appears in the examples 

 in question to grow from the lower side of the pedicel at a 

 considerable distance from the stem. There is great variability 

 in regard to this feature even between the different pedicels of 

 the same inflorescence. In some the bracts are situated upon the 

 main axis in the normal position, while in others they are seated 

 upon the pedicel 2 cm. above its connection with the stem, and 

 all intermediate conditions occur. A similar situation may be 

 observed with more regularity in the water pimpernel {Saniolus 



* Fitting, Hans, Die Beeinflussung der Orchideenbliiten durch die Bestau- 

 bung und durch andere Umstande. Zeitschrift fiir Botanik, Bd. I, S. i, 1909. 



