Hydrangea lingii G.Hoo — Narrowleaf hydrangea

Introduction

Narrowleaf hydrangea (Hydrangea lingii) is a woody shrub of southeastern China belonging to Hydrangea subg. Dichroa sect. Chinenses. In its narrow historical sense, it is a relatively small shrub with narrow elliptic foliage, short corymbose inflorescences lacking enlarged marginal sterile flowers, small pale-yellow fertile flowers, eight to ten stamens, three styles, and wingless reticulate seeds.

The modern concept is complicated because Flora of China and current global backbones combine several earlier species beneath H. lingii, most notably H. vinicolor Chun. The resulting broad description spans shrubs 0.7–2.5 m tall with leaves reaching 18 cm and calyx teeth varying from 0.5 to 2 mm—variation that partly reflects the merger of the old lingii and vinicolor concepts rather than necessarily variation within a single biological species.

Tree TSAR recognizes a narrower H. lingii. Its historical center is Fujian, where plants generally reach about 0.7–1.7 m and bear narrowly elliptic leaves around 5–9 × 1.5–2.5 cm, usually with five or six pairs of secondary veins. The flowers lack enlarged marginal sepals; fertile flowers have short ovate-triangular calyx lobes and relatively small pale-yellow broadly obovate petals. Older branches develop thin exfoliating bark, and the leaves commonly dry dark purple-red or dark brown.

The principal reason for narrowing the species is H. vinicolor. Yang et al. (2024) sampled material representing both concepts and specifically reported that H. vinicolor, although synonymized under H. lingii by Flora of China, did not form a monophyletic group with it in their plastid phylogeny. Their figure labels the vinicolor accession as H. lingii with an asterisk and explicitly identifies the starred sample as H. vinicolor.

Comparison with Hydrangea vinicolor

Character	**Hydrangea lingii**	**Hydrangea vinicolor**
Habit	Shrub ca. 0.7–1.7 m	Shrub ca. 1–2.5 m
Leaves	Narrowly elliptic, ca. 5–9 × 1.5–2.5 cm	Lanceolate to narrowly elliptic, ca. 8–15 × 2–4.5 cm, sometimes longer
Lateral veins	Usually 5–6 pairs	Usually 6–7 pairs
Leaf base	Cuneate	Broadly cuneate to obtuse, often decurrent
Petiole	Ca. 5–10 mm	Stouter, basally expanded and nearly stem-clasping
Calyx lobes	Ovate-triangular, ca. 0.5–0.7 mm	Lanceolate, ca. 1.5–2 mm, elongating in fruit
Petals	Pale yellow, broadly obovate, ca. 2.5–3 mm	White, narrowly elliptic, ca. 3.5–4.5(–5.5) mm
Historical geographic center	Primarily Fujian	Guangdong, Guangxi, Hunan, Jiangxi, and Guizhou
Yang et al. (2024)	Separate sampled lineage	Separate sampled lineage; did not group with H. lingii
Tree TSAR	Accepted	Accepted

The distinction is therefore supported by two independent historical evidence streams. Taxonomists originally recognized different morphological and geographic concepts, and a later molecular study—conducted for infrageneric classification rather than specifically to vindicate vinicolor—recovered the sampled plants separately. Tree TSAR consequently does not include H. vinicolor among the synonyms of H. lingii.

Two other names remain appropriately synonymized beneath H. lingii: Dichroa tristyla W.T.Wang & M.X.Nie and Hydrangea minnanica W.D.Han. Current POWO lists both alongside vinicolor, but Tree TSAR extracts only the latter from that synonymy.

The current evidence is still not equivalent to a nuclear population-genomic species-delimitation study. Plastid discordance can arise through introgression or chloroplast capture. The Tree TSAR treatment should therefore be understood as a testable species hypothesis: H. lingii and H. vinicolor are recognized separately unless future nuclear sampling demonstrates that their morphological and plastid distinctions occur within one freely interbreeding lineage.

Horticultural and Agricultural Uses

Narrowleaf hydrangea appears to have little established horticultural presence outside specialist collections. Its small stature, narrow glossy foliage, dark purple-brown shoots, and compact fertile-flowered inflorescences give it a subtler ornamental character than familiar lacecap hydrangeas.

Because H. vinicolor is widely synonymized beneath it, cultivated or germplasm material labelled H. lingii should be interpreted cautiously. Provenance from Fujian is particularly informative for the narrow Tree TSAR concept; material from Guangdong, Guangxi, Hunan, Jiangxi, or Guizhou should be checked against the vinicolor diagnosis rather than assumed to represent lingii.

No significant agricultural use was located.

Conservation Concerns

No formal IUCN assessment was located. POWO's automated angiosperm extinction-risk model currently predicts the broadly circumscribed H. lingii as “not threatened,” but that prediction uses a taxonomy that includes H. vinicolor and therefore should not be transferred directly to Tree TSAR's narrower species without qualification.

A useful conservation assessment will require authenticated population records under the narrower circumscription, especially in Fujian, followed by comparison with the geographically broader vinicolor lineage.

Additional Information

Flora of China — Hydrangea lingii (opens in a new tab): — Broad modern morphological treatment combining H. vinicolor with H. lingii.

Plants of the World Online — Hydrangea lingii (opens in a new tab): — Current accepted name and synonymy; differs from Tree TSAR by including H. vinicolor.

References and Further Reading

Hoo G (1951) Some new species and additional descriptions of Fukien plants. Acta Phytotaxonomica Sinica 1(2): 193–198. https://www.jse.ac.cn/EN/Y1951/V1/I2/193 (opens in a new tab)

Wei Z, Bartholomew B (2001) Hydrangea. In: Wu ZY, Raven PH (eds.) Flora of China, vol. 8. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis, pp. 411–422. https://www.iplant.cn/foc/pdf/Hydrangea.pdf (opens in a new tab)

Wei ZF (1994) A revision of the genus Hydrangea in China. Guihaia 14(2): 101–121. https://www.guihaia-journal.com/gxzwen/ch/reader/create_pdf.aspx?falg=1&file_no=199402002&quarter_id=2&year_id=1994 (opens in a new tab)

Yang X, Xue T, Gao T, Liang Y, Smets EF, Gadagkar SR, Yu S (2024) An updated infrageneric classification based on phylogenomics and character evolution in Hydrangea (Hydrangeaceae). Taxon 73(2): 503–518. https://doi.org/10.1002/tax.13158 (opens in a new tab)