Matricaria discoidea
 
Pineapple Weed

Flower Head Bottom/Side

Regina
27-June-2020

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Answers to key questions in Vascular Flora of Alberta: An Illustrated Guide leading to this genus (and species). 
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juice usually watery; NOT [juice milky]

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lowest leaves not triangular-egg-shaped to kidney shaped, not white-woolly beneath

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flower heads small to large, 1-few (rarely many) in round- to flat-topped clusters; NOT [flower heads usually small and numerous, in elongated clusters]

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involucres neither nut/bur-like nor with hooked prickles (sometimes with straight spines); NOT [involucres with short, hooked prickles, or nut/bur-like and spiny]

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receptacles hemispheric to cone-shaped; NOT [receptacles flat or +/- convex]

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involucral bracts in >= 2 rows, not enfolding the achenes; NOT [involucral bracts in 1 row, equal, each enfolding an achene]

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involucres usually with  >6 bracts; NOT [involucres with about 4-5 bracts]

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receptacles naked or with 1 row of  papery scales between the ray and disc florets; NOT [receptacles covered with bristles or scales (a few central florets sometimes bractless)]

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flower heads discoid, with disc florets only.

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pappus a minute crown or absent; NOT [pappus of short, distinct bristles or scales], NOT [pappus of hair-like or feathery bristles (at least in part)]