1981 Western States Botanical Expedition

Overview

1981 Western States Botanical Expedition

Thuja plicata (western arborvitae), 1474-81*C, grown from seed collected by Rob Nicholson in Lowell, Idaho. Photograph by Kyle Port.

Thuja plicata (western arborvitae), 1474-81*C, grown from seed collected by Rob Nicholson in Lowell, Idaho. Photograph by Kyle Port.

In September 1981, Rob Nicholson spent three weeks collecting in the Great Basin region of the Rocky Mountains. He was searching specifically for disjunct populations (small, distinct populations of plants occurring outside of their native range), in order to compare them to the larger populations of the same species. Not only can disjunct populations provide clues about a species’ historical range, but often times, members of a disjunct population will have traits which differ slightly from the main population, such as increased winter hardiness.

He covered over 5,000 miles of road in these few weeks, snaking through central Colorado to southern Colorado, Utah, and northern Arizona. He primarily sought out conifers (including the Englemann spruce, Picea englemannii) from distinct forest populations which are isolated on mountains among these desert regions. He then went to Idaho to seek out a famous disjunct population of pacific dogwood (Cornus nuttalli) which grows far outside its normal coastal range. He was surprised and excited to also find Oregon maple (Acer macrophyllum) in Idaho, also far outside of its native range. Nicholson hoped that seed from this maple would be hardier in the Boston climate than ones which had been previously tried. Arboretum records report that while this accession survived out-of-doors for a few years, it eventually perished.

Additional Resources Nicholson, Robert. “Collecting in the West.” Arnoldia 42(4) [pdf].