Skip to main content

Shrink teacost (Isodon attenuatus), Gongshan teacost (Isodon gongshanensis) and Su-Kung teacost (Isodon sukungii)

Shrink teacost (Isodon attenuatus), Gongshan teacost (Isodon gongshanensis) and Su-Kung teacost (Isodon sukungii)

NEWS - Three new species of Isodon (Schrad. ex Benth.) Spach (Ocimeae, Nepetoideae, Lamiaceae) are reported based on the latest morphology and phylogenomics of shrink teacost (Isodon attenuatus), Gongshan teacost (Isodon gongshanensis) and Su-Kung teacost (Isodon sukungii) from Mount Fanjing and Hengdua Mountains in China.

Isodon is a genus with about 140 species and is mostly distributed in subtropical to tropical Asia with two separate species endemic to Africa. The genus is most diverse in southwest China especially in the dry valleys of the Hengduan Mountains.

The genus can be distinguished from other genera of the family Ocimeae by petioles and bracteolates, calyces slightly or very 2-lipped (3/2), very 2-lipped (4/1) corollas and free filaments inserted at the base of the corolla tube. DNA loci or plastome sequencing are difficult due to the rapid radiation of the genus.

Recently, researchers from the Kunming Institute of Botany in Kunming and The Royal Botanic Gardens in Richmond reconstructed a robust phylogeny for 126 Isodon taxa using transcriptome and genome re-sequencing data.

Except for four clades (Clade I–Clade IV) found consistently in previous molecular phylogenetic studies, four subclades (Clade IVa–Clade IVd) were further recognized within the largest Clade IV that includes about 80% of the species of the genus. Meanwhile, three specimens collected during 2018–2020 are new species.

I. attenuatus is most closely related to I. villosus, but differs in having a subglabrous lamina (vs. densely to sparsely villous) with a descending base (vs. not descending), densely pubescent and glandularly pubescent inflorescences (vs. densely villous and glandularly pubescent), longer pedicels (4-6 mm vs. 2.5-4 mm), triangular calyx teeth (vs. oval) and a corolla tube that tapers towards the throat (vs. not tapers).

This species is known only from the Fanjing Mountains in Guizhou Province, China, and grows in evergreen broadleaf forests at elevations of 1600-2000 m. The specific epithet refers to the corolla tube that tapers towards the throat. The Chinese name is jiàn xiá xiāng chá cài (渐狭香茶菜).

I. gongshanensis is similar to I. rosthornii, but differs in having lanceolate (vs. triangular) and longer (c. 1 mm vs. c. 0.5 mm) teeth on the posterior petal lip, longer corolla (6-7 mm vs. c. 5 mm) with a pink posterior lip (vs. white), but without spots (vs. with reddish-purple spots) and an ovary without glands (vs. with glands).

This species is known only from Gongshan County in southwest China's Yunnan Province and occurs in mixed coniferous and broadleaf forests at elevations of 2700-2900 meters. The specific epithet is derived from the location of the new species, Gongshan County. The Chinese name is gòng shān xiāng chá cài (贡山香茶菜).

I. sukungii is similar to I. tenuifolius but differs by having longer laminae (1-4 cm vs. 0.5-1 cm long) with serrated margins (vs. entire), panicle-forming sympes (vs. single sympes not forming thirsus or panicles) and longer corollas (6-7 mm vs. 4 mm long) with straight anterior lip (vs. strongly folded).

This species is widely distributed in dry valleys along the Min River, a tributary of the Yangtze River, in Sichuan Province, southwest China and grows on dry open slopes with savanna vegetation at elevations of 1600-2700 meters. Specific name according to the late Prof. Su-Kung Wu. Chinese name is sù gōng xiāng chá cài (素功香茶菜).

Original research

Chen Y-P, Peng H, Paton AJ, Xiang C-L (2024). Three new species of Isodon (Nepetoideae, Lamiaceae) from China. PhytoKeys 246: 283-293, DOI:10.3897/phytokeys.246.130432

Dlium theDlium
Labels:

Popular Posts

Purple nutsedge (Cyperus rotundus)

Teki or purple nutsedge ( Cyperus rotundus ) is a species of plant in the Cyperaceae, an erect annual growing to a height of up to 140 cm, the leaves sprout in rows of three from the base to a length of 5-20 cm, ribbon-shaped, pointed tip and green in color. The inflorescence has a stalk with a triangular cross section and is green. The inflorescence has three to eight unequal spikes. The flower is bisexual, has 3 stamina and the pistil has three stigmas. The fruit is achene and triangular. Teki prefers dry places, but will tolerate moist soil and often grows in wastelands and in crop fields. Tubers are an important source of nutrition for migratory cranes. Source of carbohydrates in the tropics in times of famine. The initial stage forms a white fleshy rhizome, 25 mm long and in chains. Some of the rhizomes grow upright above the ground, then form a tuber-like structure from which new shoots and roots grow, new roots and new rhizomes grow. Other rhizomes grow horizontally or down...
Read more

Twoleaf nightshade (Solanum diphyllum)

Twoleaf nightshade ( Solanum diphyllum ) is a species of plants in Solanaceae, upright shrubs grow in shade, 1-2 m tall, rounded stems, dense, green-purple brown, short hairy, stopping cells, cornered young twigs and widely cultivated as plants decorate with bright yellow ripe fruit. S. diphyllum has leaves that are alternating, solitary or paired in twigs with generative organs. Some are stemmed for 1-1.5 cm. The leaves are oval to oblique round eggs, dynamic base, flat or wavy edges, tapered or rounded edges, 1-14.5 cm long, 0.5-4 cm wide and have short hair. Flowers facing leaves 5-25 mm long. Has a 2 mm handle, brownish purple, straight and unbranched. Hook 5-10 mm, greenish to brown and curved. The petals have five ears, resembling kupula, pale green, 1-5 mm long and short haired. Flowers have five crowns, coincide, star-shaped, yellowish white, 2-5 mm long. Has five stamens, free and facing the crown. Short and yellowish green pistil. The stigma is yellow, attached to the...
Read more

Limestone beads (Jacquemontia paniculata)

Limestone beads ( Jacquemontia paniculata ) is a species of plant in the Convolvulaceae. It is a herbaceous, twining climbing plant with cylindrical, branched, green stems. It grows in shrubs, teak forest floors, agricultural lands, roadsides, and abandoned areas. J. paniculata has arrow-shaped, green leaves with a central main vein and numerous pinnate minor veins. The leaves are up to 9 cm long, 7 cm wide, and have stalks up to 5 cm long. The flowers are star-shaped, about 1 cm in diameter, and bluish-white. TAXON Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Solanales Family: Convolvulaceae Subfamily: Dichondroideae Tribe: Jacquemontieae Genus: Jacquemontia Choisy in Mém. Soc. Phys. Genève 6: 476 (1833 publ. 1834) Species: Jacquemontia paniculata (Burm.f.) Hallier f. in Bot. Jahrb. Syst. 18: 95 (1893) Variety: Jacquemontia paniculata var. grandiflora Ooststr., Jacquemontia paniculata var. lanceolata S.H.Huang, Jacquemontia paniculata v...
Read more