— 247 — 



in the dunes of North- Jutland, are purely female, and these specimens 

 always stand on very dry places and were, taken as a whole, 

 smaller than the common hermaphrodite ones. Further a patch 

 of H. pilosella in a dry lawn in the Botanical Garden gave only 

 female flower-heads in the last autumn ; one of these heads has 

 been figured on the Plate (fig. 8) and will show, that, it is smaller 

 and paler than a head of the normal H, pilosella (fig. 3). 



It is likely from the cases here mentioned, that the sexuality 

 of some Hieraciiim-species under certain external circumstances 

 can be weakened. And perhaps it may be supposed that the apo- 

 gamy is a provision against this accident. Were the suppression 

 of the pollen-grains has become normal (f. i. H. excellens), the plant 

 has been able to produce at least a great many of its fruits 

 without fertilisation. A fact which may be of some interest is, 

 that both H. excellens and H. roxolanicum originate from Galizia, 

 and that I last year in Hungary (Herculesbad) collected seeds of 

 two Piloselloidea, which now, when flowering, show, that they 

 are both female; the one is a form of H. magyaricum, the other 

 belongs to the species with so-called dichotomous scapes; it then 

 seems as if the female forms were more common in the S. E. part 

 of Central-Europe. 



The report given here will, it is to be hoped, show, that the 

 Hieracia offer a great many interesting problems, and that some of 

 them bear an interest reaching far beyond the genus, but it will 

 also show, that at present we are only in the mere beginning of 

 our knowledge about these phenomena. I hope in further reports 

 to be able to explain several questions which now are unsolved, 

 but there are more problems here than one single man can 

 take up. — 



I cannot end this paper without expressing my best thanks 

 to the Director of our Botanical Gardens, Professor, Dr. E. War- 

 ming, and to our Garden-inspector Mr. A. Lange for their kind- 

 ness in placing a part of the garden at my disposal for these 

 experiments and in helping me in all possible ways. And finally 

 I have to acknowlegde my debt of gratitude to Professor W. 

 Bateson, of Cambridge, who has kindly corrected the grammar 

 and vocabulary of the English. 



Copenhagen, July 1906. 



