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A Conservation SOS: Polygonum hickmanii 
Holly Forbes 
to get overlooked, even by some of the 
sharpest botanists. When a plant is only 
a few centimeters tall and flowers later in the 
season than its more eye-catching neighbors, it 
can be even easier to miss. The Scotts Valley 
polygonum (Polygonum hickmanii) is a case 
in point. This tiny species was first described 
in 1995 and was already very rare. It occurs 
in a limited urban area in Scotts Valley, near 
Santa Cruz, California, where it is under pres- 
sure from development. Only 2,100 plants were 
observed in 1997, and in 2003, the United States 
Fish and Wildlife Service listed it as endangered 
under the federal Endangered Species Act. 
As the curator of the University of California 
Botanical Garden at Berkeley, I work with the 
national Center for Plant Conservation and a 
Pes with less-than-showy flowers tend 
coalition called California Plant Rescue. Each 
year we make an ambitious plan for conserva- 
tion fieldwork in the greater San Francisco Bay 
Area, and for 2020, we planned a packed calen- 
dar. Most of our fieldwork was derailed by the 
restrictions put in place to limit the spread of 
COVID-19, especially given the timing of the 
restrictions. Annuals and herbaceous perenni- 
als on California’s Central Coast tend to have 
a short spring cycle of growth and seed set. By 
the time permission was given to be in the field 
for just day trips, seeds had already set and been 
dispersed for many species. 
Scotts Valley polygonum, in contrast, is 
an annual wildflower that typically starts to 
germinate in December, flower from May to 
August, and set seeds in August. The species 
is now known to occur on less than an acre of 
In recent years, the endangered Scotts Valley polygonum (above) has been observed in only one wild population. 
FORBES, H. 2021. A CONSERVATION SOS: POLYGONUM HICKMANII. ARNOLDIA, 78(3): 5-6 
DAVID GREENBERGER 
