392 Reporr or THE HorricuutruRaAL DEPARTMENT OF THH 
LABORATORY STUDY OF POLLEN. 
At the same time that these observations were being made 
the pollen itself was being studied to determine if possible its 
status as a factor bearing on fertilization. This part of the 
work was wholly of a laboratory and microscopic nature, the 
only portion which took place in the field being the gathering 
of the blossoms. For this purpose the following varieties were 
selected for examination and comparison. 
TABLE I.—VARIETIES OF GRAPES SELECTED FOR COMPARISON OF 









POLLEN. 
SELF-STERILE VARIETIES. SELF-STERILE VARITIES. 
PERCENTAGE. | sd ele: 
| No. Variety. Class.! | No. Variety. | Class.1 
| 
a — 
pare. (xk. ee ee | TP Cleveners. 2. 40091) Clinton , 57 ae. 2 
Rinaria rp Siw pale Nei ed NE ATLOTE LE of 3 dines). danesyille: wae ae 1 
PUPAL Een 4c ee RAVIDEO Rc. cae o 4]. 3 | Berckmans.. 77 7. 1 
Labrusca x....... | 4 | Aminia.......] 4 | 4 | Agawam........ 2 
DLA DOTIA te haces ee» | 5 | Grein Golden.. | 4 5 | Missouri Reisling; 2 
Datmused ass SVM vi "ON Darryn. > staee 4 6 | Rogers No. 32.... 2 
Labrusca) Xtina | 7 | Wyoming.....| + yf, dalagiles <p, ieee ae 1 
LaOTUSCS. xs ye 8 | Black Eagle... 4 8) Triamphii? sits 2 
Labruses} mcf 677.48 | 9 | Massasoit:.... 4 ie 9ypiBrilliankte. 70% 2 
Labrusca Xai. a4 | Lt): eer Oes ost an. 4-1 -10-) Lindmar, . fi. ne 2 
PGCeOrnit ee <. Se Pil’) fexamer >, .* ti Batiey.- cae nae 2 




Here we have a comparison, in each instance, of two varieties 
blooming at the same or nearly the same time, with similar par- 
entage, but one variety being self-sterile and the other self- 
fertile, the object being to eliminate so far as possible all differ- 
ences which might be due to species or strain. These investi- 
gations were along the two general lines: (1) Trial of the pollen 
in sugar solution to see if it would germinate; (2) examination 
of the pollen under a microscope to see if there were any con- 
stant morphological differences between that of the self-sterile 
and self-fertile varieties. 
1The numbers under “Class ” refer to classification given by Beach in Bulletin No. 157; 
Class 1 includes varieties in which sacked blossoms gave clusters varying from perfect to 
somewhat loose; Class 2, clusters marketable—moderately compact or loose; Class 3, clusters 
unmarketable; and Class 4, self-sterile—no fruit developed on covered clusters. 
