— 239 — 



praeterea ^ parce glandulosa pilis longioribus basi nigricantibus 

 intermixes; squamae lineari-lanceolatae, albo marginatae; ligulae 

 luteae concolores. Floret ineunte Junio. 



Statio: Rasztowce pr. Skalat (Galiciae orientalis polonicae), 

 in silvis, solo calcareo; in horto botanico Hauniensi ab anno 1889 

 culta." 



H. Zahn (1904, p. 171, note) says, that H. excellens is a 

 subspecies of the H. umbelliferum N. & P. (= cymosum-magyaricum), 

 i. e. belonging to a species which is supposed to have originated 

 from a cross between H. cymosum (sectio Cymosina) and H. 

 magyaricum (sectio Praealtina), but that does not agree with 

 Blocki's statement above, that his H. excellens belongs to the 

 section Praealtina. H. Dahlstedt of Stockholm who has seen 

 dried specimens of the cultivated plant, writes that it "belongs to 

 an intermediate group between Florentina and Glomerata" ; it is 

 also cultivated in the botanical garden, Bergielund, near Stock- 

 holm. Whatever the systematic position of the plant in question 

 may be, it is certain, that it is near H. magyaricum N. & P. (H. 

 Bauhini Bess.), and that it has the same long epiterrean stolons, 

 which mostly are only leaf-bearing, but sometimes turn out to bear 

 a terminal corymb of flower-heads. For my purpose the most 

 interesting point in the characters of the form is its aborted pollen. 

 I have later found another species, H. roxolanicum Rehmann, 

 growing in the Hieracium-plot in our Garden, in which also the 

 anthers were quite empty, but hitherto I have used only H. excellens 

 for my experiments, and in this summer (1906) H. roxolanicum 

 has died. 



The experiments with H. excellens have been carried out in 

 the following way: 



Series III (H. excellens x aurantiacum). 



In the first days of June 1904 a specimen was planted in a 

 pot and placed in a window facing NE. June 15 th ; all the opened 

 flower-heads were cut off; of the two remaining corymbs the one 



(A) was shut within a cylindrical glass and the opening was closed 

 with wadding; before that some of the unopened flow T er-heads 

 moreover had been castrated (No. 45), the others were intact (No. 44). 

 June 16 th — 17 th ; the newly-opened flower-heads of the other corymb 



(B) were fertilized with the pollen of H. aurantiacum growing in the 

 Medical Quarter of the Garden (No. 46); the flower-heads of H. 



