Circaea L., 1753

Luo, Yike & Xie, Lei, 2023, A checklist of Onagraceae in the Pan-Himalaya region, Phytotaxa 597 (4), pp. 245-268 : 250

publication ID	https://doi.org/10.11646/phytotaxa.597.4.1
DOI	https://doi.org/10.5281/zenodo.7958616
persistent identifier	https://treatment.plazi.org/id/03FD5F66-FFE1-E154-3DCD-BAECFA114D7C
treatment provided by	Plazi (2023-05-22 21:28:14, last updated 2024-11-26 00:29:35)
scientific name	Circaea L.
status

Treatment

2. Circaea L. View in CoL View at ENA

Lectotype (designated by Britton & Brown 1913):— Circaea lutetiana Linnaeus (1753: 9) View in CoL .

Erect perennial herbs. Stems usually cespitose. Leaves opposite and decussate, with long petiolate. Inflorescence simple or branched racemes. Flowers 2-merous; floral tube, ca. 2.4 mm long; ovary unilocular or bilocular, 1 seed per locule; petal 2, alternate, white or pink, notched at the apex; stamens 2, opposite the sepals; filaments as same color as the petals; nectary completely within and filling the lower part of the floral tube, or elongated and protrude above the opening of the floral tube as a disc. Indehiscent capsule covered with uncinate hairs. Seed smooth, firmly inset to the inner ovary wall. Chromosome number, n = 11 ( Boufford 1982).

Circaea comprises eight species (14 taxa) ( Boufford 1982), and six species (eight taxa including subspecies) in the Pan-Himalaya region. The genus is distinctive with other genera in Onagraceae by having 2-merous flowers and indehiscent fruits covered with hooked hairs ( Boufford et al. 1990). The sister relationship between Fuchsia Linnaeus (1753: 1191) and Circaea has been confirmed by molecular phylogenetic studies ( Berry et al. 2004, Wagner et al. 2007, Xie et al. 2009).

Key to species of Circaea View in CoL View at ENA in the Pan-Himalaya region

1 Ovaries and fruits unilocular; rhizomes terminated by tubers............................................................................................................2

- Ovaries and fruits bilocular; rhizomes without tubers .......................................................................................................................3

2 Apical notch 1/2 or more length of petal; pedicels glandular pubescent; leaves with 9–15 secondary veins; combined length of mature fruit and pedicel 7.5–15 mm .............................................................................................................................. 2.6. C. repens View in CoL

- Apical notch 1/2 or less length of petal; pedicels glabrous; leaves with 4–10 secondary veins; combined length of mature fruit and pedicel 3.5–7.8 mm ........................................................................................................................................................2.1. C. alpina View in CoL

3 Nectary wholly included within the floral tube..................................................................................................................................4

- Nectary exserted beyond the floral tube.............................................................................................................................................5

4 Axis of inflorescence with glandular and nonglandular hairs.......................................................................................2.2. C. cordata View in CoL

- Axis of inflorescence glabrous or with only glandular hairs................................................................................. 2.4. C. glabrescens View in CoL

5 Stem glabrous; petal apical notch to more than 1/10–1/5 their length ................................................................... 2.3. C. erubescens View in CoL

- Stem pubescent with falcately recurved hairs; petal apical notch to more than 1/4–1/2 their length ............................ 2.5. C. mollis View in CoL

References

Berry, P. E., Hahn, W. J., Sytsma, K. J., Hall, J. C. & Mast, A. (2004) Phylogenetic relationships and biogeography of Fuchsia (Onagraceae) based on noncoding nuclear and chloroplast DNA data. American Journal of Botany 91 (4): 601 - 614. https: // doi. org / 10.3732 / ajb. 91.4.601

Boufford, D. E. (1982) The systematics and evolution of Circaea (Onagraceae). Annals of the Missouri Botanical Garden 69 (4): 804 - 994. https: // doi. org / 10.2307 / 2398997

Boufford, D. E., Crisci, J. V., Tobe, H. & Hoch, P. C. (1990) A cladistic analysis of Circaea (Onagraceae). Cladistics 6: 171 - 182. https: // doi. org / 10.1111 / j. 1096 - 0031.1990. tb 00534. x

Britton, N. L. & Brown, A. (1913) An Illustrated Flora of the Northern United States, Canada and the British Possessions, vol. 1. C. Scribner's sons, New York, 680 pp.

Linnaeus, C. (1753) Species Plantarum. Laurentii Salvii, Stockholm, 1200 pp.

Wagner, W. L., Hoch, P. C. & Raven, P. H. (2007) Revised classification of the Onagraceae. Systematic Botany, Monographs 83: 1 - 240.

Xie, L., Wagner, W. L., Ree, R. H., Berry, P. E. & Wen, J. (2009) Molecular phylogeny, divergence time estimates, and historical biogeography of Circaea (Onagraceae) in the Northern Hemisphere. Molecular Phylogenetics and Evolution 53: 995 - 1009. https: // doi. org / 10.1016 / j. ympev. 2009.09.009