“All good abides with him who waiteth wisely.” Henry David Thoreau in A Week on the Concord and Merrimack Rivers.
Studies using herbarium specimens are increasingly used to investigate the effects of climate change on plant phenology. But such studies can be called into question if there are biases in how the specimens were collected.
In a study of blunt-lobed spicebush in East Asia using 88 herbarium specimens and photos, it was found that male plants flowered 25 earlier on average in comparison with female plants and there was surprisingly little overlap in when they flowered. Could male and female plants really have separate flowering times? If so, how could they cross-pollinate and produce seeds?
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| Specimens with male flowers were collected three weeks earlier than specimens with female flowers. |
It is likely that plants with male flowers were collected preferentially during the flowering season as male flowers are more conspicuous than female flowers. Plants with female flowers were likely sampled more frequently later in the season as female flowers are long persistent while male flowers quickly fall off.
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Male spicebush flowers are more conspicuous that female flowers. Researchers working with dioecious plants need to be aware of the biases of collectors in terms of favoring male plants during the flowering season. |
