Bolick M R
University of Nebraska State Museum, Lincoln 68588-0514.
Nebr Med J. 1991 Jun;76(6):175-7.
Pollen counts in 1988, 1989, and 1990 revealed the presence of grass pollen from April through October. Grass pollen counts begin to rise in late May and early June and peak in the middle of that month. Counts fall in July but rise again to a lower peak in August and early September.
1988年、1989年和1990年的花粉计数显示，从4月到10月都有草花粉存在。草花粉计数在5月下旬和6月初开始上升，并在该月中旬达到峰值。7月计数下降，但在8月和9月初再次上升至较低峰值。
