| 词条 | Helenium microcephalum |
| 释义 |
| image = Helenium microcephalum1.jpg | regnum = Plantae | unranked_divisio = Angiosperms | unranked_classis = Eudicots | unranked_ordo = Asterids | ordo = Asterales | familia = Asteraceae | tribus = Helenieae | genus = Helenium | species = H. microcephalum | binomial = Helenium microcephalum | binomial_authority = DC. 1836 | synonyms_ref = [1][2] | synonyms = *Helenium oöclinium A.Gray, syn of var. ooclinium
}}Helenium microcephalum is a North American perennial plant in the sunflower family, commonly known as smallhead sneezeweed.[3] It is found in the southwestern and south-central United States and northern Mexico.[3][4]Helenium microcephalum is an annual herb up to {{convert|120|cm|ft|abbr=on}} tall, with wings running down the sides of the stems. Leaves are narrow and elliptical. One plant can have 300 or more small spherical or egg-shaped flower heads, generally no more than 12 mm (half an inch) in diameter. Each head can have 400 or more minuscule disc flowers {{convert|1.2|–|2.4|mm|in|abbr=on}} across, each yellow or yellow-green toward the bottom but brown or red toward the tip. There are also 7-13 red or yellow ray flowers.[5]
References1. ^The Plant List, Helenium microcephalum DC. {{Taxonbar|from=Q15548108}}{{Asteroideae-stub}}2. ^International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) see section 60.6 3. ^Biota of North America Program 2014 county distribution map 4. ^1 Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100 5. ^1 2 Flora of North America, Helenium microcephalum de Candolle, 1836. Smallhead sneezeweed 4 : Flora of the United States|Plants described in 1836|Helenium|Flora of Mexico |
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