Aspidistra viridiflora Vislobokov & Nuraliev, 2017

Vislobokov, Nikolay A., Kuznetsov, Andrey N., Kuznetsova, Svetlana P., Romanov, Mikhail S. & Nuraliev, Maxim S., 2017, Aspidistra viridiflora (Asparagaceae, Nolinoideae), a new species from Vietnam, Phytotaxa 313 (2), pp. 203-209 : 203-207

Aspidistra viridiflora Vislobokov & Nuraliev , sp. nov. ( Figs. 1 , 2 )

Diagnosis: Aspidistra viridiflora is morphologically similar to A. hainanensis species complex but differs in colour of the perigone (green vs. purple outside), stigma completely white above and anthers inserted at the middle of the perigone tube.

Type:— VIETNAM, Kon Tum province, Sa Thay district, Ro Koi municipality, Chu Mom Ray National Park, 33 km WNW of Kon Tum city, in the forest, 14° 29’ 04’’ N, 107° 42’ 52’’ E, elev. 980 m, collected in nature on 7 April 2015, M. S. Nuraliev, A. N. Kuznetsov, S. P. Kuznetsova 1280, the herbarium specimen prepared from the living cultivated plant on 17 February 2017 by N. A. Vislobokov and M. S. Romanov (holotype MW!).

Plant perennial, evergreen, herbaceous, rhizomatous, completely glabrous ( Figs. 1A, B ). Rhizome creeping, epigeous, with very short internodes, Ø 8.9 –16.6 mm. Roots grey, Ø 1.6 –3.3 mm. Rhizomes with regularly repeating units, each comprising distichously arranged phyllomes: 5–12 cataphylls followed by 2–3 foliage leaves ( Figs. 1C, D ). Cataphylls oblong, up to 12 cm long, 23–25 mm wide. Foliage leaves not divided into petiole and lamina, gradually narrowing towards base. Leaf base dark to light green, sulcate adaxially, 4.7–5.9 mm wide. Leaf blade dark to light green, linear, distally narrowly acuminate, 56–91.2 cm long, 1.3–3.6 cm wide, with small denticles along margin, with 1–2 secondary veins at each side of midvein. Midvein prominent abaxially ( Figs. 1E, F ). Peduncle (specialized reproductive shoot) whitish green, ca. 2.2 cm long, Ø 2.6 –2.9 mm, with 3 greenish, widely ovate, 6.1–8.8 mm long, 10 mm wide (being flattened) distichously arranged scale leaves. Flower solitary at top of peduncle, upright or slightly slanted. Perigone cup-shaped, 13.1–14.9 mm long, Ø 11.9 –12.9 mm; tube outside green to greenish white, smooth and lustrous, inside reddish purple with 6 white vertical stripes (in lower two thirds) at radii of stamens and also white at bottom, 8.6–9.8 mm long; lobes 6, outside whitish green, sometimes with purple spots at base along margin, smooth, inside green with purple spots gradually turning purple towards base, deltoid, 5.4–7.2 mm long, 5.9–6.7 mm wide, slightly curved outward, bearing 4 prominent longitudinal keels at adaxial side. Stamens 6, inserted at middle level of perigone tube considerably below stigma, at the same radii with tepals; filaments white, cylindrical, 0.5–1 mm long; anthers 1.3–2.3 mm long, 1.6–1.9 mm wide, introrse ( Fig. 2 ). Pistil table-shaped, 5.5–6.5 mm long; style white, cylindrical, ca. 4.3 mm long, Ø 1.8 –2.8 mm; stigma white above, white with purple spots along margin below, disk-shaped, slightly 6-lobed, ca. 1.8 mm thick, Ø 6.5 –7.3 mm, with 3 straight radial grooves and 3 bifurcated radial grooves. Ovary inconspicuous, superior, 3-locular. Young fruits green, spherical, Ø 11–13 mm ( Fig. 1G ); ripe fruits unknown.

Additional specimens examined:—Living plant cultivated in MBG RAS ; garden number: 2015. 11381; interim number in collection CMR15 AL01 ; collection number: 1280. Liquid collection of vegetative organs collected in type locality on 28 March 2015, M. S. Nuraliev, A. N. Kuznetsov, S. P. Kuznetsova 1201 .

Etymology:—The specific epithet refers to green colour of the perigone of the new species.

Distribution and ecology:—The new species is known only from Chu Mom Ray National Park, where it is rather common at the left terrace of the river at least within a 1.2 km radius. The forest stand at river terrace is characterized by height 24–32 m and the trunks 40–80 cm diameter at breast height (DBH).

Phenology: — Aspidistra viridiflora was flowering in December–March under cultivation. Aspidistra viridiflora was observed fruiting in the wild in March–April, most of the fruits were immature.

Shoot system: —Rhizome of A. viridiflora consists of regularly repeating units (elementary shoots). Each unit comprises several distichously arranged cataphylls followed by two or three foliage leaves ( Fig. 3A ). The rhizome is creeping and flattened in the plane of substrate. The orthostiches occupy lateral (left and right) positions. Though the number of cataphylls within a unit is usually even (most frequently 6 or 8), it varies from 5 to 12 including odd numbers ( Fig. 3C ). Sometimes, in the first elementary shoot after branching, cataphylls are followed by a single foliage leaf ( Fig. 3D ). Foliage leaves of at least five successive elementary shoots are present simultaneously on a shoot. New elementary shoots (and their foliage leaves) develop irrespectively to the seasons and asynchronously in different plants. Cataphylls enclose and protect young foliage leaves and usually disintegrate and abscise by the time the leaves are fully emerged. Both cataphylls and foliage leaves have wide bases. Each cataphyll is represented by open sheath whose left and right margins overlap each other at the side opposite to cataphyll midvein. Pattern of this overlapping makes the rhizome dorsoventral, as the physically lower margin (i.e., facing the substrate) is always the outer one. In the foliage leaves, the sheathing base is short, and its margins do not overlap. Foliage leaves also contribute to the dorsoventrality of the rhizome, as their petioles are displaced towards the physically upper side of the creeping shoot. Each cataphyll subtends an axillary bud, whereas the axils of foliage leaves lack visible buds. Within an elementary shoot, the proximal axillary buds are usually dormant, while a few (1–3) distal ones develop without a long delay ( Fig. 3B ); they are either reproductive (forming peduncles with a terminal flower) or vegetative (forming vegetative shoots of the next order). Thus, the peduncles occupy axillary position; they are observed in the axils of cataphylls of the two most recently developed elementary shoots. Our observations on A. viridiflora support the idea of monopodial architecture of vegetative shoots in the genus Aspidistra ( Vislobokov et al. 2014b) .

Taxonomic relationships: — Aspidistra viridiflora possesses linear leaves crowded into groups and trimerous flowers with table-shaped pistil. These features show that A. viridiflora is close to A. hainanensis Chun & How (1977: 533) species complex sensu Tillich & Averyanov (2012), but it differs in colour of the perigone (green vs. purple outside), stigma completely white above (vs. partly purple) and position of anthers, which are inserted at the middle (vs. bottom) of the perigone tube. Aspidistra viridiflora resembles A. lubae Averyanov & Tillich (2014: 755) in some floral features, but strongly differs in leaf and shoot morphology: the foliage leaves of A. viridiflora are not divided into petiole and lamina (vs. petiolate) and crowded into groups by three (vs. solitary), and the rhizome of A. viridiflora is creeping (vs. erect).

Figures

FIGURE 1. Aspidistra viridiflora in natural habitat. A, B. Habit of the plant. C. Rhizome, view from above; foliage leaves and roots cut off. D. Fragment of rhizome with one elementary shoot: eight scales followed by three foliage leaves. E. Foliage leaf, adaxial side. F. Foliage leaf, abaxial side. G. Young fruit.All photos by M.Nuraliev.

FIGURE 2. Aspidistra viridiflora, flower structure. A Flower, oblique view. B. Flower, top view. C. Flower, side view. D. Flower, longitudinal section. E. Flower, side view. F. Flower, longitudinal section. G. Flower, longitudinal section, oblique-top view. All photos made from holotype by M.Romanov.

FIGURE 3. Shoot system of Aspidistra viridiflora. A. Diagram of the rhizome. The diagram shows an entire elementary shoot (its phyllomes are green), five distal phyllomes of an elementary shoot of the previous generation (black) and two initial phyllomes of the subsequent elementary shoot (blue). Axillary buds (vegetative and generative) are shown as red ellipses. Each elementary shoot possesses several cataphylls (lines on the diagram) followed by foliage leaves (filled figures).The diagram shows physical orientation of the rhizome in relation to the ground (bottom side on the figure).B–D.Schemes of rhizomes.Each scheme shows distal part of a shoot, which comprises two completely developed elementary shoots (their phyllomes are black and green) and an undeveloped terminal elementary shoot (its phyllomes are blue). Elementary shoots of previous generation are shown in dotted lines. Cataphylls are shown as short claw-shaped figures and foliage leaves as long claw-shaped figures; axillary buds (vegetative and generative) are shown as red half-ellipses.Arrowhead indicates shoot apical meristem. B. Rhizome with cataphylls subtending the peduncles with anthetic flowers (red clavate structures) on the two most recently developed elementary shoots. C. Rhizome with elementary shoot (green) with odd number of cataphylls. D. Branched rhizome, first elementary shoot (black) possessing a single foliage leaf.