| 词条 | Oclemena | ||
| 释义 |
|name = Oclemena |image = Oclemena nemoralis, Pancake Bay PP.jpg |image_caption = Oclemena nemoralis (Bog-aster) |regnum = Plantae |unranked_divisio = Angiosperms |unranked_classis = Eudicots |unranked_ordo = Asterids |ordo = Asterales |familia = Asteraceae |tribus = Astereae |genus = Oclemena |genus_authority = E.L.Greene |synonyms_ref= |synonyms=
|}}Oclemena E.L.Greene, is a small genus of North American flowering plants in the aster tribe within the (sunflower family).[1][2] It is native to northeastern North America, found in wet or dry woodlands, and sometimes in clearings in the woods, or in acid bogs and peat.[3] The finely woolly stem grows in a zig-zag fashion to a height {{convert|30|-|100|cm|ft|0|abbr=on}}. It may be red at its base.[3] The lanceolate leaves are numerous, arranged in a spiral whorl around a single stem. They can be sharply toothed along the margin (as in O. acuminata) or smooth (as in O. nemoralis). The leaves contain sessile resin glands.[3] The flower heads consist of flat-topped pink to rose-violet ray florets and yellow disk florets. There are one to a few on a plant, growing on a slender peduncle. The disk flowers are abruptly expanded at the top. The scarious floral bracts consist of narrow chlorophyllous bands, tinted with purple along the midrib.[3] The stipitate ovaries are generally compressed and show on the surface minute, cylindrical glands. The fruit is a glandular achene with a double pappus of two bristled whorls.[3] The chromosome base number is x=9. The Kew database [https://web.archive.org/web/19971118034813/http://www.rbgkew.org.uk/cgi-bin/web.dbs/genlist.pl?COMPOSITAE Vascular Plant Families and Genera] categorizes Oclamena under the genus Aster L. But taxonomically, Oclemena belongs to the North American clade of the tribe Astereae, as a basal member of one of the main branches.[4]
References{{Commons category}}1. ^[https://www.biodiversitylibrary.org/page/396130#page/7/mode/1up Greene, Edward Lee. 1903. Leaflets of Botanical Observation and Criticism 1(1): 4–5] in English 2. ^Tropicos, Oclemena Greene 3. ^1 2 3 4 Flora of North America Vol. 20 Page 78 Oclemena Greene 4. ^Brouillet, L., G.A. Allen, J.C. Semple, and M. Ito. 2001. ITS phylogeny of North American asters (Asteraceae: Astereae). Abstract. Botany 2001, August 2001. Albuquerque, N.M. 5. ^Flann, C (ed) 2009+ Global Compositae Checklist 6. ^The Plant List, search for Oclemena 7. ^Biota of North America Program 2013 county distribution maps
3 : Astereae|Asteraceae genera|Flora of North America |
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