Seed Study - Grindelia squarrosa

Grindelia squarrosa - Curlycup Gumweed
Grindelia squarrosa - Curlycup Gumweed

NPS Photo

Species: Grindelia squarrosa
Common name: curlycup gumweed

Seedling identification: Very similar to the Solidago genus; however, Grindelia seedlings are much more "toothy" and have glands at the base of the teeth. Leaves are lanceolate to spatulate and rough to the touch.


Grindelia squarrosa – curlycup gumweed
Average number of good seeds per gram bulk matter: 420; 314 (depending on where collected)
Average number of good seeds per gram cleaned: 600
Commercial estimates of seeds per gram: n.a.
Percent seed: n.a.
Percent live: n.m.
Collection dates: October 20 and 21
Collection effort: 57 grams in 3 person hours
Collection notes: Easy to collect in large amounts. Rubbing alcohol is useful for cleaning sticky sap off of clippers and fingers.
Cleaning notes: Seed in bulk measurement was only scraped out of the involucres while the clean seed measurement was hard seeds only.

Last updated: January 23, 2018

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