Monday, January 01, 2018

Dakota buckwheat (Eriogonum visheri)

Grand River National Grasslands, Perkins County, SD
Photos from August 2013 and 2014. 
Rare across its range. Limited to the western half of the northern Great Plains. 
Edaphic endemic, annual. Endemic means unique to a geographic area, in this case, the north-western plains. Edaphic means specific to a particular soil, in this case, exposed, often disturbed, badland claystones, mudstones, siltstones.  
These mobile, elusive populations shift across a given badland outcrop from year to year. It is our suspicion that the location of the following year's population is partly determined by the prevailing direction of the strongest winter winds and the direction of runoff during rains and snowmelt. 
Being an annual with such particular tastes, it is inherently at risk of extirpation. One bad stretch of weather, disturbance, or pathogen and the seed bank viability may have lapsed. This is the life of an annual in the wild. 
That being so, viabilty of the seeds in the seedbank is essential for the survival of this species. Apparently, it has innate dormancy, some seeds resisting germination despite ideal conditions, ensuring the survival of some seeds into the next year in the event that the current crop fails. It has been observed that Eriogonum annuum has one of the largest seed banks in the Nebraska Sand Hills, yet only 6% of the seeds germinate in any given year. 
As always, it is worth noting that there are several other species of Eriogonum out there that are very similar in appearance to E. visheri, such as E. gordonii, E. trichopes, E. corvilleanum, E. cernuum, E. rotundifolium, and E. gracile.

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