— 231 — 



Experiments carried out in 1904 (Series II). 

 In June of 1904 the castration experiments were continued in 

 exactly the samme manner as in 1903. 



(1) H. pilosella L. from the same clump as Series 1 4. June 

 11 th 1904; 4 heads were castrated; the seeds were ripe at July 1 st ; 

 sown 1 ) immediately; germinated; planted out in September 1904; 

 flowered and fruited copiously in June— July 1905; discarded (No. 51). 



(2) H. sabstoloniflorum, Näg. & Pet., f. longipilum (determ. 

 Dahlstedt), growing in a lawn in the Garden (near the Observa- 

 tory). June 11 th 1904; 15 heads were castrated; the seeds were 

 ripe at July 4 th , sown immediately; germinated; planted out in 

 September; flowered and fruited copiously in June— July 1905. 

 (No. 53). 



(3) H. flagellare Willd. (revis. Dahlstedt), growing together with 

 the foregoing. June 11 th 1904; 20 heads were castrated; some of 

 them did not develop; the seeds of the developed heads ripe July 

 4 th ; germinated and planted out as above; flowered and fruited 

 copiously in June— July 1905 (No. 52). 



(4) H. pilosella L., growing in a lawn near the Taxus-shrub- 

 bery in the Garden; the specimens bear ripe fruits, but some of 

 them are empty. June 1 l lh 1904; 10 heads were castrated, but did 

 not develop well; June 20 th , all faded. New castration gave no 

 result, as the grass of the lawn was cut. 



Experiments carried out in 1905 (Series VI). 



(1) H. venosum L. A specimen in our herbarium, collected 

 in Sayre, U. S. A., 1903 by Mr. W. C. Barbour, had ripe seeds, 

 which were sown in July 1904 and germinated; in May 1905 

 they were planted out and flowered copiously from the end of 

 June (No. 54). — July 2 nd 1905; 10 heads were castrated, but no 

 full seeds were developed. The heads which were intact, gave 

 ripe seeds (93 barren fruits to 91 full). Again in September a 

 good many heads were castrated, but with the same negative 

 result; at that time the intact heads gave more barren and fewer 

 full fruits (355 barren to 128 full). The full fruits have germi- 

 nated in 1906. 



(2) H. Gronovii Willd. ; seeds obtained from the Missouri Bo- 

 tanical Garden, sown in the spring of 1905, germinated, trans- 



1 ) Always in baked soil. 



