Leafl. Bot. Observ. Crit.1: 4. 1903
e North America.
Species 4 (4, including 1 hybrid, in the flora).
G. L. Nesom (1994b) summarized the taxonomic history, composition, and affinities of Oclemena, which he considered a monophyletic group. He suggested affinity to the eastern North American Doellingeria. Differences with Doellingeria include heads nodding in bud, 1-nerved, acute phyllaries not proximally indurate, triangular disc corolla lobes, fusiform and slightly compressed cypselae shorter than involucres, with 5–8 non-resinous nerves, and faces with sessile glandular hairs. Xiang C. and J. C. Semple (1996), using RFLPs on cpDNA data, showed O. reticulata associated with Doellingeria instead of Oclemena. The current composition of Oclemena is supported by phylogenetic analysis of ITS data (Semple et al. 2002). Oclemena appears to be among the basal lineages of the North American clade of Astereae. Genetic proximity between these basal lineages is illustrated further by the discovery of an F1 hybrid between O. nemoralis and D. umbellata in upper Michigan (L. B. Gerdes 1998; Nesom 2001b). This suggests that these genera have preserved the symplesiomorphic ability to hybridize. Their relative morphologic conservatism may have facilitated survival of the F1 progeny. Given its frequent occurrence in northeastern North America and occasional confusion with other taxa (e.g., Eurybia radula), the hybrid O. ×blakei also is described below.
|1||Leaves 12–30 or 11–18, some subpetiolate to short-petiolate, blades elliptic-oblong, oblanceolate, obovate, obovate-elliptic, or ovate-elliptic, (2–)10–45(–50) mm wide; heads or (1–)5–46(–67+); rays white to pinkish||> 2|
|1||Leaves 20–100+, sessile, blades oblanceolate to oblong or linear to linear-lanceolate, 1–8 or 4–16 mm wide; rays pink to pale pink, seldom white; heads borne singly or 2–35+||> 3|
|2||Stems straight; leaf margins revolute, scabrous, entire or sometimes serrate (teeth coarse, ± obtuse); rootstocks woody caudices, rhizomes deep under surface; array branches ascending, angles with stems acute; disc corollas funnelform; cypselae 6–8-ribbed, strigillose||Oclemena reticulata|
|2||Stems flexuous; leaf margins flat, ciliate, serrate (teeth sharp, acuminate); rootstocks herbaceous, white rhizomes near surface; array branches arched-ascending, initially ± right-angled relative to stems; disc corollas narrowly campanulate; cypselae 3–5-ribbed, glabrate to sparsely strigose||Oclemena acuminata|
|3||Leaves crowded, blades linear to linear-lanceolate, 10–60 × 1–8 mm, margins strongly revolute; heads borne singly or in loose corymbiform arrays; rays pale to deep pink (seldom white)||Oclemena nemoralis|
|3||Leaves crowded to dispersed, blades oblanceolate to oblong, 20–80 × 4–16 mm, margins flat to slightly revolute; heads usually in corymbiform arrays, sometimes borne singly; rays white to pink||Oclemena ×blakei|
|Author||Luc Brouillet +|
|Common name||Aster +|
|Etymology||Derivation unknown +|
|Illustrator||Yevonn Wilson-Ramsey +|
|Synonym||Aster Acuminati +, Aster Nemorali +, Aster Orthomeris + and Galatella Calianthus +|
|Taxon name||Oclemena +|
|Taxon parent||Asteraceae tribe Astereae +|
|Taxon rank||genus +|
|Volume||Volume 20 +|