''Oclemena'' is a small genus of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

n flowering plants in the tribe

Astereae Astereae is a tribe of plants in the family Asteraceae that includes annuals, biennials, perennials, subshrubs, shrubs, and trees. They are found primarily in temperate regions of the world. Plants within the tribe are present nearly worldwide di ...

within the family Asteraceae. It is native to northeastern

, found in wet or dry woodlands, and sometimes in clearings in the woods, or in acid bogs and peat.Flora of North America Vol. 20 Page 78 ''Oclemena'' Greene
/ref> The finely woolly

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

grows in a zig-zag fashion to a height . It may be red at its base. The lanceolate

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

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. 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

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s consist of narrow

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...

ous bands, tinted with purple along the midrib. The stipitate ovaries are generally compressed and show on the surface minute, cylindrical

gland In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

s. The fruit is a glandular

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

with a double pappus of two bristled whorls. The chromosome base number is x=9. The Kew databas
Vascular Plant Families and Genera
categorizes ''Oclamena'' under the genus ''Aster'' L. But taxonomically, ''Oclemena'' belongs to the North American

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of the tribe Astereae, as a basal member of one of the main branches. ; SpeciesBiota of North America Program 2013 county distribution maps
/ref> File:Oclemena-acuminata01.jpg, Whorled Wood Aster (''Oclemena acuminata'') File:Oclemena-nemoralis01.jpg, Bog Aster (''Oclemena nemoralis'') * '' Oclemena acuminata'' (Michx.) Greene: Whorled wood aster, sharpleaf aster, white wood aster GA TN NC WV VA OH PA NJ DE NY CT RI MA VT NH ME NS NB QUE ONT

NFL The National Football League (NFL) is a professional American football league that consists of 32 teams, divided equally between the American Football Conference (AFC) and the National Football Conference (NFC). The NFL is one of the major ...

LAB Lab most often refers to: * Laboratory, a facility to conduct scientific research Lab or LAB may also refer to: Places * Láb, a village near Bratislava in western Slovakia * Lab (river), in north-eastern Kosovo People * ISO 639 code for the an ...

* '' Oclemena × blakei'' (Porter) G.L.Nesom (''O. acuminata'' × ''O. nemoralis'') : Blake's aster MI PA NJ NY CT RI MA VT NH ME NS NB QUE ONT * ''

Oclemena nemoralis ''Oclemena nemoralis'', common names bog aster or bog nodding aster, is a plant native to the northeastern United States. Its range extends into southeastern Canada. Conservation status It is listed as endangered in Connecticut and Pennsylvani ...

'' (Ait.) Greene: bog aster, bog nodding aster. MI DE MD PA NJ NY CT RI MA VT NH ME NS NB QUE ONT * ''

Oclemena reticulata ''Oclemena'' is a small genus of North American flowering plants in the tribe Astereae within the family Asteraceae. It is native to northeastern North America, found in wet or dry woodlands, and sometimes in clearings in the woods, or in acid b ...

'' (Pursh) G.L.Nesom: pinebarren whitetop aster. FL GA AL SC

References

* Semple, J. C., S. Heard and Chunsheng Xiang, 1996. The Asters of Ontario (Compositae: Astereae): ''Diplactis'' Raf., ''Oclemena'' Greene, ''Doellingeria'' Nees and ''Aster'' L. (including ''Canadanthus'' Nesom, ''Symphyotrichum'' Nees and ''Virgulus'' Raf.). ''University of Waterloo Biology Series'' No. 30: 1-88. * Semple, J. C., S. B. Heard and L. Brouillet. 2002. Cultivated and native asters of Ontario (Compositae: Astereae): ''Aster'' L. (including ''Asteromoea'' Blume, ''Diplactis'' Raf. and ''Kalimeris'' (Cass.) Cass.), ''Callistephus'' Cass., ''Galatella'' Cass., ''Doellingeria'' Nees, ''Oclemena'' E.L. Greene, ''Eurybia'' (Cass.) S.F. Gray, ''Canadanthus'' Nesom, and ''Symphyotrichum'' Nees (including ''Virgulus'' Raf.). University of Waterloo Biology Series No. 41: 1-134. * {{Taxonbar, from=Q7076565 Astereae Asteraceae genera Flora of North America