Chamaenerion Seguier 1754
Creators: name: Luo, Yike
name: Xie, Lei
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Onagraceae
Chamaenerion

description: 1. Chamaenerion Ség., pro parte.
Lectotype (designated by Pfeiffer 1873):— Chamaenerion angustifolium (Linnaeus 1753: 347) Scopoli (1772: 271).
≡ Epilobium angustifolium L.
= Epilobium subg. Chamerion Rafinesque (1818: 266). ≡ Chamerion (Raf.) Raf. ex Holub (1972: 85).
Type:— Epilobium amenum Rafinesque (1818: 266).
Herbs perennial, erect. Stems usually simple, rarely branched, glabrous or strigillose. Leaves subsessile, alternate, spirally arranged, rarely subopposite or subverticillate; the underground blades scalelike; the basal blades small, triangular-ovate to lanceolate; cauline blades linear to lanceolate to elliptic, often subcoriaceous. Inflorescence simple, raceme or spikelike, rarely branched. Flowers somewhat zygomorphic, 4-merous; floral tube absent, nectar at base of style and stamens; petals pink, purple, or rarely white, without a lobe; stamens 8, subequal; pollen in monads; style erect when stigma deflexed; stigma deeply 4-lobed, receptive on inner surfaces with multicellular papillae. Fruit capsulate, slender, 4-loculed, loculicidal. Seeds many, with terminal coma of silky hairs. 2 n = 36, 72, and 108 (Chen et al. 1992).
The genus Chamaenerion, comprising eight species (nine taxa), is divided into two sections (Tacik 1959), sect. Chamaenerion and sect. Rosmarinifolium Tacik (1959: 254). All species are restricted to the northern hemisphere, and four of them are in the Pan-Himalaya region. This genus was previously included in Epilobium. However, molecular analysis provided strong support (100% BS) for Chamaenerion as a monophyletic group sister to Epilobium (Baum et al. 1994). Therefore, taxonomists divided Epilobium s. l. into two genera, Epilobium and Chamerion (Chen et al. 1992, Wagner et al. 2007). Sennikov (2011) agreed this treatment but proposed that Chamerion was the later heterotypic synonym of Chamaenerion.
Key to species of Chamaenerion in the Pan-Himalaya region
1 Bracts much shorter than cauline leaves; leaves linear to lanceolate, submarginal vein distinctly; seeds with inconspicuous chalazal collar................................................................................................................................................................... 1.1. C. angustifolium
- Bracts about half the length of cauline leaves; leaves narrowly ovate or elliptic to lanceolate-elliptic, submarginal vein inconspicuous; seeds with distinct chalazal collar ......................................................................................................................................................2
2 Stems subglabrous to sparsely strigillose, only rarely densely strigillose; primary leaf veins obscure; seeds 1.2–2.1 mm; style glabrous .................................................................................................................................................................... 1.2. C. latifolium
- Stems densely strigillose; primary leaf veins distinct; seeds 1–1.3 mm; style pubescent on lower half ...........................................3
3 Secondary leaf veins conspicuously reticulate or anastomosing; plants 30–120 cm tall; sepals 11–15 mm; petals 8–14 mm ........... ...............................................................................................................................................................................1.4. C. conspersum
- Secondary leaf not conspicuously anastomosing; plants 20–45 cm tall; sepals 15–20 mm; petals 17–25 mm ...... 1.3. C. speciosum
description: Published as part of Luo, Yike & Xie, Lei, 2023, A checklist of Onagraceae in the Pan-Himalaya region, pp. 245-268 in Phytotaxa 597 (4) on page 247, DOI: 10.11646/phytotaxa.597.4.1, http://zenodo.org/record/7958600