Corydalis nanchuanensis S.R. Yi, 2021

Zhang, Bu-Yun, Xiao, Jin-Fei & Yi, Si-Rong, 2021, Corydalis nanchuanensis (Papaveraceae), a new species from Chongqing, China, Phytotaxa 510 (2), pp. 163-170 : 164-169

Corydalis nanchuanensis S.R. Yi , sp. nov. ( Figs. 1–4 A1–G1 ).

Type:— CHINA. Chongqing: Nanchuan district, Sanquan town , Dumatou , Jinfo Shan , 29°03′23″N, 107°12′14″E, in rocky crevices, elev. 950 m, 16 March 2019, YSR 8126 (holotype KUN; isotypes KUN, PE) .

Diagnosis: — Corydalis nanchuanensis is morphologically similar to C. sheareri Moore (1875: 225) , a species mainly distributed in south China and Vietnam in having tubers, divided lower bracts, conical corolla spurs, rounded stigmas, and larger elaiosomes (usually longer than seeds), but differs by having tapering-to-base (vs. uniformly sized) stems; entire (vs. usually crenate) leaf lobes, straight (vs. declined) pedicels in fruit, concave (vs. subacute) apices of outer petals, white (vs. usually purple) abaxial surface of inner petals, and reticulate (vs. tuberculate) seeds.A morphological comparison between C. nanchuanensis and C. sheareri in detail is given in Table 1.

Description: —Perennial herb. Newly formed tubers of seedlings subglobose or subellipsoid, subsequent tubers forming on old tubers, ellipsoid, constricted in the middle, 0.5–1.9 × 1.0– 2.9 cm, pale yellow; fibrous roots filamentous, slender, 5–10 cm long. Stems 1 or 2, arising from the top of tubers, green with pale purple spots, prismatic, juicy. Basal leaf usually 1, often gradually withering during anthesis, petiole 6–20 cm long, leaf blade triangular-ovate, 10–15 × 10–30 cm, 2–4-pinnate; petioles of primary pinnules 3–5 cm long; petioles of the second pinnules shorter and the third pinnules subsessile; ultimate pinnules entire or divided, cuneate at base, sometimes slightly concave at apex; cauline leaves 1 or 2, similar to basal leaves but smaller. Racemes 5–15 cm long, 8–20-flowered; lower bracts broadly obovate, palmately lobed, 1.5–2.3 × 1.5–2.5 cm; upper bracts obovate to elliptic, 4.5–6.0 × 3.2–3.6 mm, short-mucronate at apex, cuneate at base. Pedicles 8–15 mm long; elongating to 1.5–3.0 cm long in fruit. Sepals scaly, irregularly lobed, ca. 2 × 1 mm. Flowers greenish white; outer petal limbs entire to slightly sinuous with purplish red tips, slightly concave, mucronate, crest ca. 1 mm high; upper petals 2.7–3.0 cm long; corolla spurs tapering to tip, straight or slightly curved downward, 1.4–1.7 cm long; nectary extended through ca. 1/3 of spur, obtuse at apex; lower petals spatulate, 1.4–1.8 cm long, with a spurlet at base (ca. 0.5 mm long); inner petals pandurate, 5–7 mm long, crests exceeding apices by ca. 1 mm; pistil 1.2–1.5 cm long, ovary linear, 0.9–1.2 cm long, 0.8–1.1 mm in diam.; style ca. 3 mm long, stigma rounded, with 12 papillae (two pairs of papillae of the base commissural respectively). Capsule narrowly oblong, slightly flat, 2.5–3.5 cm long. Seeds up to 50 in 2 rows, obliquely ovate, 1.0–1.3 × 0.7–0.8 mm, reticulate, black, lustrous, slightly concave in ventral surface; elaiosome larger, 1.5–2.0 × 1.0– 1.4 mm.

Etymology: —The specific epithet of the new species refers to its type locality, i.e. Nanchuan district in Chongqing, China.

Phenology: —Flowering March to April; fruiting April to May.

Distribution and habitat: —The new species is currently known only from Nanchuan district in south-west Chongqing, China. It grows in rocky crevices at elevations between 900–1,600 m above sea level ( Fig. 5 ).

Common name (assigned here): —Nan Chuan Zi Jin (Chinese name: *川ĀƂ).

Additional specimens examined (paratypes): — CHINA. Chongqing: Nanchuan district, Sanquan town, Mazui , 29°03′14″N, 107°17′22″E, in rocky crevices, elev. 1,150 m, 23 March 2018, YSR 8004 ( KUN, PE) ; Chongqing: Nanchuan district, Sanquan town, Huangcaoping , 29°02′37″N, 107°11′15″E, in rocky crevices, elev. 1,370 m, 30 March 2018, YSR 8014 ( KUN, PE) ; Chongqing: Nanchuan district, Sanquan town, Huangcaoping , on moist rocks, elev. 960m, 27 February 2020, YSR 8014 ( KUN) ; Chongqing: Nanchuan district, Sanquan town, Huilongsi , 29°04′27″N, 107°12′14″E, in rocky crevices, elev. 1,170 m, 9 April 2020, YSR 842 3 ( KUN) ; Chongqing: Nanchuan district, Sanquan town, Huilongsi , 29°04′27″N, 107°12′14″E, in rocky crevices, elev. 1,170 m, 9 April 2020, YSR 8470 ( KUN) ; Chongqing: Nanchuan district, Delong Town , on rocks, elev. 1,300 m, 16 April 1980, Z. Y . Liu 0144-01 ( IMC), Z. Y . Liu 0144-02 ( IMC), Z. Y . Liu 0144-03 ( IMC), Z. Y . Liu 0144-04 ( IMC), Z. Y . Liu 0144-05 ( IMC) ; Chongqing: Nanchuan district , 13 April 1982, S . X. Tan , Z. L . Li & J. L . Zhang 3084 ( IMC) ; Chongqing: Nanchuan district, Sanquan Town, Jinfo Mountain , roadside, elev. 1,600 m, 12 March 1999, Z. Y . Liu 973488-01 ( IMC), Z. Y . Liu 973488-02 ( IMC), Z. Y . Liu 973488-03 ( IMC), Z. Y . Liu 973480 ( IMC) .

Notes:—Specimens of this new species were first collected by Zheng-Yu Liu in 1980 and deposited at IMC. They were identified as “ Corydalis nanchuanensis Z.Y. Liu ” by Zheng-Yu Liu and Bai-Quan Shi on the determination slips. Specimens of the new species were later collected also by other collectors.

Corydalis nanchuanensis may belong to Corydalis sect. Asterostigma Wu & Chuang (1999: 103) by having rounded stigmas and narrowly oblong capsules. However, its tapering-to-base stems and tubers with the new ones formed directly on old ones correspond to the characters of C. sect. Duplotuber Ryberg (1960: 223). Further studies are needed to confirm the sectional placement of this species.

Figures

FIGURE 1. Holotype sheet of Corydalis nanchuanensis.

FIGURE 2. Corydalis nanchuanensis. A. Habit. B. Flower with a lower bract. C1. Low bract. C2–C4. Upper bracts. D. Capsule. E. Stigma. F. Seed. Drawn from YSR 8423.

FIGURE 3. Corydalis nanchuanensis. A. Habitat. B. Leaf. C. Inflorescence. D. Tubers. E. Bracts, showing variation of size and shape. F. Stigma of unopened flower, showing lateral (F1) and frontal (F2) views; arrows indicate a pair of commissural papillae. G. Flowers, showing frontal (G1) and lateral views (G2), and lateral view of the dissected flower (G3). H. Spurlet (indicated by upward arrow) and sepal (indicated by the left arrow). I. Nectary. J. Capsule. K. Longitudinal section of capsule. L. Seed, with the white part being the elaiosome. M. Lateral view of seed under SEM. N. Seed surface ornamentation under SEM.

FIGURE 4. A1–G1. Corydalis nanchuanensis. A2–G2. C. sheareri. A. Inflorescences. B. Flowers, showing frontal (left) and lateral (right) views. C. Stigmas, showing lateral (left) and frontal (right) views.D. Seeds. E. Lower parts of plants. F. Leaves. G. Bracts, showing lower, middle and upper bracts from left to right.

FIGURE 5. Distribution of Corydalis nanchuanensis (●).