1913] MARTIN—POLLEN OF TRIFOLIUM PRATENSE 117 
TABLE 1l—Continued 





Solution phe T. pratense T. hybridum T. repens 
’ Maltose...| 1.1695\| Bursting a bursting; 25 | No bursting; 25 
1.3989 er cent germi-| per cent germi- 
1.4619 Gatien ion 


Percentages of maltose and dextrose mixed gave about the same results 






Lactose...| 0.5848 | Bursting Bursting Bursting 
ae ies ae fa gens i 50 | ee — — 50 per cent germi- 
tio tion; som 
res ‘co bursting 
vi 0.8772 " 50 per pe germi-| 50 per cent germi- 
nation; som nation; some 
ursting : burstin 
= 1.0233 . 50 per cent germi-| 50 per cent germi- 
1.1695 nation; noburst-| nation; no bars t- 
iv3247 | ing ing 
4619 
Arabinose 1.9743 : Bursting Bursting : 
a 55 3 . | 50 per cent germi-) 50 per cent germi- 
nation; some nation; some 
bursting bursting : 
4 1.9999 . | 50 per cent germi-| 50 per cent germi- 
nation; noburst-| nation; no burst- 
ing ing 

carbon dioxide showed that the supply of these gases was not the 
limiting factor. Small dishes made by cutting off glass shells 
about one-half inch from the bottom and containing the pollen 
in very shallow depths of sucrose and levulose solutions, which did 
not permit bursting, were placed in wide-mouthed bottles and 
attached to oxygen and carbon dioxide tanks. No germination 
resulted from a three-hour exposure to an increased pressure of 
these gases. In table III the results obtained with other media 
are given. 
Results obtained by use of parchment paper and animal mem- 
brane with pollen of Trifolium pratense and 
T. hybridum 
Small squares of parchment paper were soaked in distilled 
water and in 0.5848, 0.731, and 0.8772 volume-normal sucrose 
solutions and then dried on filter paper until surplus moisture was 
removed, mounted on slides, and after application of pollen placed 
