Stellaria nagae Sindhu Arya

Arya, Sindhu, Vishnu, Kalarikkal Walsan & Kumar, Venugopalan Nair Saradamma Anil, 2025, A new species of Stellaria (Caryophyllaceae) from North-East India, Phytotaxa 693 (4), pp. 270-276 : 271-274

Stellaria nagae Sindhu Arya & V.S.A Kumar sp. nov.

Type: — INDIA. Nagaland: Kohima, 25.6751 N, 94. 1086 E, 30 December 2022, Arya & Vishnu 1294 (holotype: UCBD!, isotype: UCBD!).

Diagnosis: — Stellaria nagae is similar to S. sikkimensis Hooker filius (1874: 230) from which differs with respect to shape and length of bract (linear, more than 4 mm in S. nagae vs. ovate-lanceolate, up to 8 mm in S. sikkimensis ), shape and length of sepal (oblong exceeding the length of petals vs. ovate to lanceolate equal or shorter than length of petal), petals (not fused at the base vs. fused till mid region of the petal), number of stamens (5 vs. 8–10), shape and size of capsule (oblong-ovoid, 1.2 cm long vs. ovate, less than 6 mm long), seed surface architecture (tubercles spinulose with few papillae vs. tubercles short flat topped with abundant papillae), pollen morphology (visible frequency of pores 19, ektexinous bodies fused vs. visible frequency of pores 14, ektexinous bodies free)

Description (micromorphology):— Perennial herb, up to 0.6 m high, stem terete, purplish-green glabrous. Leaves opposite, obovate-lanceolate, sessile on the apex and petiolate on the basal part of the stem; leaves 1.7–2.4 × 1.0– 1.7 cm, petiole ca 5 mm terete, glabrous, base rounded, sometimes cuneate, margins entire or slightly wavy, apex shortly acuminate, surfaces glabrous or sparsely pubescent with simple cilia, mainly on veins, dark green above, pale beneath. Flowers white, 5-merous, 6–8 mm long, as across, in few- to many-flowered panicle of terminal and axillary; sessile flowers ca. 5 mm are seen on the nodes of the plant, peduncles simple, ciliate; bracteoles linear-lanceolate 2–4 mm, acute to acuminate apex; bract foliaceous linear ca 2.5–3.7× 0.5–0.7 mm; Sepals 5, linear-lanceolate to lanceolate, 5–6 × 1.2–1.3 mm, base cordate, apex narrowly acuminate to aciculate, margins broadly scarious, both surfaces glabrous, glossy. Petals 5, exceeding to sepals, sometimes lobes oblong-elliptic, 7–8 × 0.3–0.6 mm, 2-lobes from the mid region till the base, apex round, white. Stamens 4 arrangement in an alternate manner, 1–1.5 mm; filaments white, nectar at base, anther brown-black or even white. Ovary green, narrowly ovoid, 1.8–2.5 mm; styles 3, white, 2.5–3 mm long, apex curved outwardly. Capsule yellow-brown, narrowly ovoid to elliptcal, 1/2 shorter than persistent sepals, 1.0– 1.5 mm, 8- valved; valves narrowly lanceolate, acute apex. Seeds 4–10, brown-black, orbicular to suborbicular, 0.7–0.8 mm.

Description (macromorphology):— Pollen grains are spheroidal, pantoporate with ca. 11.28–12.14 µm with 19– 20 visible pores. Pore margin or aperture is well demarcated. Size of pore 3.5–4.6 µm. The surface is micro-echinate. Echines blunt or appear like dots that join to form a reticulate appearance. Ektexinous bodies present inside the pore, minute, numerous and fused.

Seeds are reniform with base circular measuring 0.763 –0.872 × 0.872 –0.930 mm. Margin wavy, tubercles with spinulose appearance scattered uniformly in the marginal and central zone. Papillae are concentrated on the arms of the tubercles, appears like dots. Scattered mammilate ornamentation is observed throughout the tubercles.

Etymology:— The specific epithet ‘Nagae’ honours the Naga tribe of the state Nagaland from where the specimen was collected for the first time.

Phenology:— Flowering and fruiting from August to December.

Habitat and distribution:— It is found in moist and shady places along the muddy slopes at an elevation above 2330 m a.s.l. It is known currently only from Kohima area of Nagaland, India.

Conservation status:— Stellaria nagae is known from only Nagaland Kohima district at an elevation of 2330 m a.s.l.. It grows along the muddy slopes with 10–30 scattered individuals per population. However, we are not sure of its occurrence in the other region of Northeast India, Hence, in the absence of thorough study, we prefer to assess S. nagae as DD (Data deficient) (IUCN 2012).

Taxonomic notes:— Stellaria nagae belongs to the Stellaria patens group, which comprises of ten taxa ( Kafle et al. 2024). The Stellaria patens group is characterized by leaves linear to linear-lanceolate, bract foliaceaous or scaly, and sepals 1/4 longer than petals. S. nagae has foliaceous bract, a trait shared by S. sikkimensis , S. decumbens var. polyantha Hooker filius (1874: 235), and S. mainlingensis Zhou (1983: 693) S. nagae differs from S. polyantha in terms of pedicle length (1–4 mm in S. polyantha vs. 6–10 mm in S. nagae ) leaves (villose vs. glabrous), petals (shorter than sepals vs. exceeding the sepals); and differs from S. mainlingensis in terms of peduncle (5–30 mm long in S. mainlingensis vs. 6–10 mm long in S. nagae ) and petals (slightly longer than sepals vs. exceeding the sepals). The differences between these four species are summarized in Table 1.

sikkimensis .

Additional specimens examined:— INDIA. Nagaland Kohima district 25.6751 N, 94. 1086 E, 31 December

2022, Arya & Vishnu 1287 ( UCBD).