Meconopsis autumnalis P.Egan, 2011

Egan, Paul A., 2011, Meconopsis autumnalis and M. manasluensis (Papaveraceae), two new species of Himalayan poppy endemic to central Nepal with sympatric congeners, Phytotaxa 20 (1), pp. 47-56 : 48-50

Meconopsis autumnalis P.Egan , sp. nov. (series Robustae Prain) ( Fig. 1 . & Fig. 3a .)

Meconopsis autumnalis a speciebus floribus flavis seriei Robustae florescentia multo postea differt.

Type:— NEPAL. Central Nepal , Ganesh Himal ( Rasuwa District ), Tulo Bhera Kharka – Jaisuli Kund, 28°12’N, 85°13’E, 4160 m, Miyamoto et al. 9440053 (holotype E!, 2 sheets [ E00107717 , E00107665 ], isotypes KATH!, TI) .

Erect monocarpic herbs, 110–160 cm. Stem 2.2–3.1 cm in diameter at base; taproot elongated, to 3 cm wide, yellow-orange lactiferous. Indumentum densely puberulent with scattered 5–9 mm pale fawn to orange barbellate bristles. Basal leaves in large rosettes, pubescent throughout, though glabrous at maturity, leaving only slender capillary bristles (to 10 mm) on the margins; petioles 11–25(–31) cm; lamina distinctly pinnatisect at base, pinnatifid only shortly from leaf apex, broadly oblong, 33–55 × 8–16 cm; segments noticeably parted in 3–5 opposite to sub-opposite pairs, oblong or ovate, to 4.0 × 2.2 cm, pinnatilobate at the margin, the lobes acute to obtuse. Cauline leaves with indumentum similar to basal leaves; petioles present in lower cauline leaves, sessile in upper; lamina progressively smaller upwards, deflexed on stem and semiamplexicaul attached, with large auricles prominent at the base, narrow-oblong, pinnatilobate to pinnatifid, the lobes entire and broadly rounded or subacute. Inflorescence densely paniculate and markedly columnar in outline, 50–250 flowered; cymules laterally branched, 3–8(–12)-flowered, the uppermost flowers solitary. Flowers bowl to saucer-shaped, semi-nutant to lateral-facing. Bracts leaf-like, at base of peduncles and pedicles. Peduncles 11–21 cm, widely spreading during anthesis, elongating to 15–29 cm and ascending in fruit. Pedicels 6–17 cm. Buds broadly ellipsoidal to ovoid, sparsely covered with ascending, barbellate bristles. Petals 4(–6), pale yellow, obovate to suborbicular, 4.3–5.6 × 4.1–5.5 cm, occasionally widely spaced, only overlapping a short distance from the base. Filaments pale yellow, anthers yellow-orange. Ovary obviously stipitate and with large receptacle, densely covered with orange ascending bristles. Style 8–25 mm, stout. Stigma yellow, capitate, (3–) 5–8 mm, 6–8-lobed. Capsule ovoid to ellipsoidal, 1.5–2.7 × 0.9–1.4 cm, dehiscing by 6–8 valves; indumentum moderately dense, spreading to ascending.

Flowering: —Late July–September.

Ecology: —Sub-alpine pastures, stream margins and grassy alpine slopes on edges and in openings of Abies forest, in association with Rumex , Arisaema , Stellaria , Nepeta , Persicaria , Aster , Swertia , and dwarf shrubs such as Berberis , Rhododendron and Juniperus , in stony, humus-rich soils. Locally abundant.

Elevational range: — 3300–4200 m.

Distribution: —Restricted to southeast Ganesh Himal, central Nepal.

Etymology: —Named for its autumn flowering.

Additional specimen seen (paratype): — NEPAL. Central Nepal , Ganesh Himal ( Rasuwa District ), Jaisuli Kund (Jagesor Kund), 28°14’N, 85°11’E, 3965 m (13,000 ft), Stainton 4028 ( BM!, 4 sheets) .

Meconopsis autumnalis is a member of the series Robustae Prain, which is characterised by long, branched inflorescences, large overwintering rosettes, and a monocarpic-perennial habit in which flowering usually only occurs after 3–5 years. Unlike most other series of Meconopsis that have centres of distribution in south- western China ( Chuang 1981), series Robustae is almost exclusively Indo-Himalayan ( Table 1.) and seems to represent a monophyletic lineage ( Yuan et al. 2002) of 12 species, seven of which are endemic to Nepal. In the aggregate of yellow-flowered species of the series, M. autumnalis is morphologically intermediate between M. napaulensis De Candolle (1824: 121) (sensu Grey-Wilson 2006b) and M. paniculata (D.Don) Prain (1896: 316) , but clearly differs from the former by its significantly taller stature, larger flowers, both wider and longer leaves, larger capsules and orange pubescence (fawn in M. napaulensis ), and from the latter in its smaller size (and subsequent greater density of the inflorescence), yellow-green stigmas, narrower capsules with spreading as opposed to densely appressed pubescence, and in its largely auriculate, deflexed cauline leaves (usually lateral-facing in M. paniculata ). Meconopsis autumnalis differs from both M. napaulensis and M. paniculata in its distinctly larger stigmas and longer pedicels (a mean of 10 cm in M. autumnalis during anthesis, and 7 cm and 6 cm in M. napaulensis and M. paniculata respectively).

Delimitation of M. autumnalis has required particularly careful examination of the morphological relationship with the closely related M. paniculata ; a partially sympatric and highly variable species widely distributed over a large geographic area ( Giri & Lal 1989, Kingdon-Ward 1930), as listed in Table 1. However, despite the reputation of M. paniculata as one of the most polymorphic species of Meconopsis , surprisingly few infraspecific taxa have been delimited. Only M. paniculata var. elata Prain (1896: 316) has been described, although this was not maintained in a subsequent monograph ( Taylor 1934). Leaves vary considerably in M. paniculata , while pubescence and stigma characters are much less variable and are diagnostic of the species ( Cobb 1989, Grey Wilson 2006b). In the field it was observed that these characters were sufficiently distinct even in sympatric populations to consistently separate the two species. Furthermore, the upper inflorescence of M. autumnalis retains wide laterally-branched peduncles with long pedicels, which render a distinctly columnar outline ( Fig. 3a .), whereas that of M. paniculata is much less branched and shortly pedicellate. Meconopsis autumnalis and M. paniculata scarcely overlap in their respective flowering times, allowing an ecological differentiation to be made between the two species (as further discussed below).

The field notes for Stainton 4028 (reproduced in part in Grey-Wilson 2006b) separate M. paniculata from what was noted as a second ‘easily distinguishable’ species of Meconopsis subsequently collected in the Ganesh Himal, and, when growing together, ‘no intermediate forms were seen’. Despite suggestion as to its novelty, the specimen (which now refers to M. autumnalis ) remained as ‘ Meconopsis sp. ’ without formal status afforded, though two later determinations included M. longipetiolata G. Taylor (1932: 41) . However, neotypification of M. longipetiolata by Debnath & Nayar (1987) placed this species type locality as Langtang valley, Rasuwa district; thereby justifying synonymy under M. napaulensis (sensu Grey-Wilson 2006b) after the complex surrounding the latter was clarified (see Table 1.).

Figures

FIGURE 1. Meconopsis autumnalis P.Egan A. Basal (rosette) leaf. B. Lower cauline leaf. C. Deflexed upper cauline leaves. D. Peduncle and flower section. E. Flower showing widely spaced petals. F. Gynoecium, with large receptacle. Scale: 4 cm. Illustration credit: S. Bradley.

FIGURE 3. A. Habit of M. autumnalis (photo taken 17 August 2008, credit: P. Egan). B. Habit of M. manasluensis (photo taken 8 August 2008, credit: M. Watson). Scale: 30 cm.