| 词条 | Helenium thurberi |
| 释义 |
| image = | regnum = Plantae | unranked_divisio = Angiosperms | unranked_classis = Eudicots | unranked_ordo = Asterids | ordo = Asterales | familia = Asteraceae | tribus = Helenieae | genus = Helenium | species = H. thurberi | binomial = Helenium thurberi | binomial_authority = A.Gray 1883 }}Helenium thurberi is a North American plant in the sunflower family, commonly known as Thurber’s sneezeweed.[1] It is native to Mexico (Baja California Sur, Sinaloa, Nayarit, Chihuahua) and the southwestern United States (Arizona).[1][2]Helenium thurberi is an annual herb up to {{convert|100|cm|in|round=0.5|abbr=on}} tall, with small wings running down the sides of the stems. Leaves are lance-shaped. One plant can produce up to 120 flower heads, in a branching array. Each head has an egg-shaped or conical disc that may contain 500 or more minuscule disc flowers each {{convert|1.0|–|1.3|mm|in|abbr=on}} across, each yellow toward the bottom but brown or reddish-brown toward the tip. There are no ray flowers.[3] References1. ^Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100 {{Taxonbar|from=Q15559459}}{{Asteroideae-stub}}2. ^Biota of North America Program 2014 county distribution map 3. ^1 Flora of North America, Helenium thurberi A. Gray, 1883. Thurber’s sneezeweed 4 : Flora of Mexico|Plants described in 1883|Flora of Arizona|Helenium |
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