taxonID	type	description	language	source
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	diagnosis	Diagnosis: The new species seems to be allied to Corydalis petrophila Franch. based on vegetative and floral morphology, but it can be differentiated very easily from the later based on having 1 – 2 - flowered racemes (vs. 2 – 9 - flowered); whitish flowers with yellow apex (vs. white or pale grayish purple); leaf margins entire (vs. bluntly dentate); lamina sparsely verrucose adaxially on veins (vs. glabrous on both surfaces); upper and lower bracts compound (vs. upper bract simple and lower bract sometimes compound); upper leaves with a pair of lanceolate stipules (vs. with auriculate membranous stipules); upper petal with acute lateral lobes (vs. short, obtuse lateral lobes) and spur conical (vs. cylindric, slightly tapering). Corydalis shiyomiensis also bears a resemblance to Corydalis leptocarpa Hook. f. & Thomson in leaf shape and vegetative habit, but differs considerably in floral characters. Corydalis shiyomiensis also bears a resemblance to C. leptocarpa Hook. f. & Thomson in leaf shape and vegetative habit, but differs clearly in reproductive and foliar characters. The new species has 1 – 2 - flowered racemes (vs. 2 – 9 - flowered); corolla white to cream with a yellowish apex (vs. purple or white); leaf margins entire (vs. coarsely crenate-dentate); lamina sparsely verrucose adaxially on veins (vs. glabrous); stipules lanceolate (vs. auriculate); sepals rounded, fimbriate-dentate (vs. rounded, peltate, finely dentate); capsule elliptic-obovoid (vs. linear). Additionally, the upper petal of C. shiyomiensis possesses acute lateral lobes (vs. obtuse lateral lobes in C. leptocarpa).	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	materials_examined	Type: — INDIA. Arunachal Pradesh: Shi Yomi, Tato, 28 ˚ 31´46 ̋ N / 94 ˚ 23´32 ̋ E, 1512 m, 06 April 2025, Madhusudhan Khanal 2105 A (holotype: ARUN), Madhusudhan Khanal 2105 B (isotype: G. B. Pant North East Regional Centre Herbarium).	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	description	Description: Perennial herb up to 25 cm tall. Rhizome 1 – 2 cm long, tuberous, fusiform, with an apical rosette of leaves; roots slender, long, arising from the surface of the rhizome, dense towards apex. Stems few to many, 1 – 2 branched with laxly arranged alternate compound leaves. Leaves subsimilar; petiole 4 – 8 cm long, vaginate at base; blade 3 – 5 × 3 – 6 cm, broadly ovate to oblong, biternate to triternate, glabrous on both surfaces, adaxially dark green and abaxially light green, abaxial surface often sparsely verrucose at veins; primary leaflets petiolulate, 0.6 – 3.2 cm long; secondary leaflets shortly petiolate to sessile, obovate to broadly ovate, base cuneate, deeply 3 - divided; segments obtuse, entire; uppermost leaf sometimes smaller, more shortly stalked and less divided; lamina ternate or rarely simple, with a pair of lanceolate membranous whitish stipules. Raceme lax, 1 – 2 flowered; lowermost bract often like uppermost leaf, upper less divided or subentire. Pedicel 0.5 – 1 cm long in flower, 0.8 – 1.3 cm long in fruit. Sepals rounded, 1 – 2 × 1 – 2 mm, fimbriate-dentate, membranous, whitish. Corolla white or creamy white with a yellowish apex. Outer petals yellowish at apex and whitish towards base. Upper petal 1 – 1.3 cm long excluding spur, broadly triangular with an obtuse to broadly acute apex and acute lateral lobes, dorsally with a 1 – 2 mm high short undulate crest that tapers towards the apex and towards the spur. Lower petal 1 – 1.2 × 0.3 – 0.4 cm, with broad claw and obtusely triangular limb, adaxially with a 0.5 – 1.5 mm wide crest at apex, saccate in lower 1 / 3 with an additional prominent pouch close to base. Spur 1.4 – 1.9 cm, conical, slightly downcurved in distal half; nectary ca. 1 / 2 as long as spur. Limb of inner petals 0.5 (– 0.6) cm, dorsally 3 - ribbed; apex obtuse; central rib low, slightly overtopping apex. Stigma square, with simple papillae along the apical margin and with geminate papillae in the basal corners and (submarginally) lateral. Capsule reflexed from straight erectopatent pedicel, dorsiventrally flattened, elliptic to obovoid, 1.2 – 1.5 × 0.3 – 0.4 cm, 15 – 20 seeded, biseriate; style 2.5 – 4 mm long. Seeds 1 – 1.5 mm, smooth, with lobed elaiosomes. (Fig: 1 – 2)	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	etymology	Etymology: The species is named after the type locality Shi Yomi district of Arunachal Pradesh, India.	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	biology_ecology	Phenology: Flowering: April – May, fruiting: May – June.	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	distribution	Distribution: Corydalis shiyomiensis is known only from Tato village, ShiYomi district of Arunachal Pradesh, India.	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	biology_ecology	Habitat: Found along the roadside growing on decaying leaf litter at 1512 m, associated with Terminalia myriocarpa, Alpinia sp, Ophiorrhiza rupicola, Begonia ziroensis etc. (Fig. 1)	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
8C588479FFB6DB49E49AFB6F8BB6FB4D.taxon	conservation	Conservation status: Corydalis shiyomiensis is known from a single site in Arunachal Pradesh, where 12 flowering individuals were observed. This site is located on the roadside near to a tribal village and the locals are dependent on the surrounding forests for their livelihood. As the highway extension project progresses, the habitat of the new species can be destroyed. The Area of Occupancy is calculated using GeoCAT following Bachman & Moat (2012) as 4 km 2. Plants were observed to set fruits but little is known about the species’ biology. Based on the limited known data related to occurrence, the species can be assessed as Critically Endangered [CR B 2 ab (iii)] following IUCN guidelines (IUCN Standards and Petitions Committee 2024). However, the habitat is vast and the chance of finding this species in adjoining areas can’t be ruled out. Plants are small and hides well among the shrubby undergrowth. More species-specific surveys are needed to understand the biology of this species.	en	Khanal, Madhusudhan, Sivaranjani, S., Singpho, Jaseng, Sarkar, Shuvadip, Kasaju, Saroj Kumar, Lidén, Magnus, Rai, Santosh Kumar, Kumar, Devendra (2025): Corydalis shiyomiensis (Papaveraceae), a new species from Arunachal Pradesh, India. Phytotaxa 721 (1): 87-92, DOI: 10.11646/phytotaxa.721.1.6, URL: https://doi.org/10.11646/phytotaxa.721.1.6
