384 Eepokt of the Horticultural Department of the 



to have tne eame effect, but only one incomplete test was made 

 witli this material in this series. 



See also Series V. 



■Seines IV. — BordemiT mixture made as in Series ITT compared 

 with an aqueous solution of sugar cane alone. — Bordeaux mixture 

 made as for Series III and diluted to 100 parts in 10,000 of the 

 2 per ct, aqueous sugar solution wholly prevented the germina- 

 tion of rose pollen in culture 30 while in the corresponding 

 culture containing the sugar solution alone there were many 

 germinations. 



Series V. — Culture media as in Series TIT. — The media used in 

 Series III when tested on pollen of Virginia creeper, Ampelopsis 

 qtiinquefolia, showed a like effect in kind only to a slightly less 

 degree than with the blackberry pollen. In the cane sugar solu- 

 tion in water alone 75 per ct. of the pollen germinated; in the 

 aqueous solution of cane sugar with 2 parts in 10,000 of the 

 Bordeaux mixture C added, 67 per ct. germinated; with 50 parts 

 in 10,000 added, 4 per ct. germinated; with 100 parts and with 

 200 parts in 10,000 added there was no germination. The copper 

 arsenite and lime in culture 37 prevented germination as did also 

 lime alone in culture 36, 



Series VI. — 'Culture media of this Series duplicate those used in 

 Series ITT except culture 21. — Pollen of Japan ivy Ampelopsis 

 tricuspidata, tested in the media used in Series III and V showed 

 76 per ct. germination in the cane sugar solution alone; 93 per ct.^ 

 in the medium containing two parts of Bordeaux mixture O in 

 10,000; no germination took place in the media containing respec- 

 tively 50 parts, 100 parts and 200 parts of the Bordeaux mixture 

 C in 10,000. In the medium cointaining copper arsenite and lime 

 there was no germination. 



From these investigations it appears that if before pollination 

 occurs the stigmatic surface of the pistil should be covered either 



^This culture contained but 15 pollen grains while the cane sugar solu- 

 tion just mentioned contained 119 pollen grains. Judging from general 

 experience with these cultures it seems quite probable that had the former 

 culture contained an equal number of pollen grains the percentage of 

 germination would have been no higher than it was in the latter culture. 



