Hairy crown loosestrife (Lysimachia pubiflora) from Hubei Province, China, similar to Lysimachia jinzhaiensis

NEWS - Hairy crown loosestrife (Lysimachia pubiflora Q.L.Gan, Z.Y.Li & H.Xu, sp. nov.) from western Hubei Province, China is similar to Lysimachia jinzhaiensis S. B. Zhou & Kun Liu 2014, but can be distinguished from all other species in Subgenus Lysimachia and Sect. Lysimachia nummularia by its pubescent and woody corolla.

Lysimachia L. in Primulaceae (sensu lato) comprises about 180 species distributed mostly in temperate and subtropical regions of the Northern Hemisphere with a few species in Africa, Latin America and Oceania. “Flora of China” records 138 species in China distributed mostly in the southwestern Karst region.

About 20 new endemic species have been discovered in China, mainly in the vast mountainous region south of the Huai River highlighting Central China as a hotspot for Lysimachia diversity. In June 2014, during an expedition in Fang County, western Hubei Province, Qi-Liang Gan discovered a specimen of Lysimachia that is new to science.

L. pubiflora is most similar to L. jinzhaiensis in several characteristics, including a quadrangular stem, glandular streaks on leaves, petals, and corollas, and the presence of a single axillary flower with unequal petal lobes. It also has a yellow corolla with an orange-red base.

However, L. pubiflora has flagella on the stem (vs. none in L. jinzhaiensis), hairy young stems and calyx lobes (vs. glabrous), calyx lobes 4.5–5 mm long (vs. 6–8.5 mm), and anthers 1.1–1.3 mm long (vs. ca. 1.5 mm). The new species can be easily distinguished from all other species in Sect. Nummularia by its serrated and pubescent corolla.

The new species flowers from late May to early July and fruits from mid-July to late August. L. pubiflora is endemic to two small towns in Fang County, confined to a narrow limestone valley located between the neighboring villages of Tanjiawan and Nantang. It grows along roadsides, water ditches, sparse shrubs on hillsides, at the edge of sparse forests at elevations of 690-712 meters.

The main companion plant species include trees such as Populus adenopoda Maxim., Quercus serrate var. brevipetiolata (A. DC.) Nakai, Platycarya strobilacea Sieb. & Zucc., Broussonetia papyrifera (L.) L’Hér. ex Vent., Vernicia fordii (Hemsl.) Airy Shaw, Pinus massoniana Lamb.

Shrubs such as Cotinus coggygria var. pubescens Engl., Mallotus apelta (Lour.) Müll. Arg., Buddleja officinalis Maxim., Pyracantha fortuneane (Maxim.) Li, Zanthoxylum armatum DC., Coriaria nepalensis Wall., Rhus chinensis Mill., Salix wallichiana Anderss., Indigofera bungeana Walp., Ficus heteromorpha Hemsl., Lindera glauca (Sieb. & Zucc.) Bl., Rosa banksiae var. normalist Regel.

The herbs consist of Miscanthus floridulus (Lab.) Warb. Schum's ex. & Laut., Anemone hupehensis Lem., Geum japonicum var. chinense F. Bolle, Agrimonia pilosa Ledeb., Duchesnea indica (Andr.) Focke, Aster albescens (DC.) Hand.-Mazz., Leersia japonica (Makino) Honda, Pteridium aquilinum var. latiusculum (Desv.) Underw. ex A. Heller, Pteris vittata L., Cyrtomium tsinglingense Ching & K. H. Shing ex K. H. Shing, and others.

Climbing plants include Clematis armandii Franch., Biancaea decapetala (Roth) O. Deg., Dalbergia mimosoides Franch., and Smilax glauco-china Warb.

The ecosystem is highly vulnerable to human activities. Discovered in 2014, the species has shown significant population fragmentation due to road construction, deforestation for agriculture and livestock grazing. The population size is estimated at around a thousand individuals. The researchers propose to classify it as ‘Endangered’.

DESCRIPTION

Herbs perennial. Rhizome horizontal, below-ground, 5–12 cm long, with adventitious roots at the nodes; stems usually 3–5 caespitose, 50–120 cm long, quadrangular, pubescent, at least when young, with a spreading habit, distal parts of stems and branches usually slender and smaller leaved, forming the flagelliform runners that usually root at the 1–3 distal nodes. Leaves opposite, rarely 3-whorled in the upper section of stems; petioles 0.5–2.5 cm long, adaxial sides shallowly grooved, abaxial sides rounded, narrowly winged, margins pilose, amplexicaul at the base; leaf blades broadly ovate to deltoid-ovate, 1.5–9.5 cm long, 1–6.5 cm wide, with acute or subobtuse apices, broadly cordate, subrounded or truncate, rarely cuneate at the base (on the runners), margins entire or slightly undulate, densely scattered with transparent glandular striations that sometimes turn purple when dry, glabrous adaxially, and abaxially sparsely pubescent along the midrib when young, becoming glabrate with age; lateral veins in 4–6 pairs, with the lowest 1–2 pairs arising from the base, the others alternating, midrib and lateral veins impressed adaxially, raised adaxially, veinlets inconspicuous. Flowers solitary in axils of leaves; pedicel 1.1–2.5 cm long, usually shorter than subtending leaves, sparsely pubescent. Calyx 5–5.5 mm long, 5–parted almost to the base, connate part ca. 0.5 mm, lobes elliptic or elliptic-lanceolate, unequal, 4.5–5 × 1.5–2 mm, densely transparent glandular striate, the stripes becoming purple when dry, sparsely pilose outside; corolla yellow, with an orange or orange-red base, rotate, 2–2.3 cm in diam., 5-parted, tube 1–1.5 mm long, lobes narrowly lanceolate, 10–12 mm long, 2.5–3 mm wide, sparsely transparent glandular striate, the stripes becoming black-purple when dry, glabrous inside, glandular-pubescent outside and along margins; stamens 5, adnate to the base of the corolla tube, erect, yellow, glabrous, filaments basally connate into a tube ca. 2 mm long, free parts 4–6 mm long, anthers basifixed, oblong, 1.1–1.3 mm long, open by lateral slits; pistil glabrous, ovary globose, ca. 1.5 mm in diameter, the style filiform, 7–8 mm long, stigma obtuse, slightly wider than the style. Capsule subglobose, 3–4 mm in diam., glabrous. Seeds dark brown, rhombic, 0.5–1 mm long, 3–4 angled, glabrous.

Original research

Xu H, Xu S-Z, Gan Q-L, Li Z-Y (2024). Lysimachia pubiflora (Primulaceae), a new species from Hubei, China. PhytoKeys 249: 269-275, DOI:10.3897/phytokeys.249.137900

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