Aspidistra revoluta H.Zhou, S.R.Yi & Q.Gao, 2016

Zhou, Hao, Yi, Si-Rong, Gao, Qi, Huang, Jie & Wei, Yu-Jing, 2016, Aspidistra revoluta, a new species from limestone areas in Chongqing, China, Phytotaxa 257 (3), pp. 280-286 : 281-284

Aspidistra revoluta H.Zhou, S.R.Yi & Q.Gao sp. nov. ( Figs. 1 , 2 )

It can be distinguished from the other Aspidistra species by its unique umbrella-like pistil with large revolute stigma lobes that bent down and touch the base of the perigone.

Type: — CHINA. Chongqing Municipality: Nanchuan District, Jinfoshan Mt., from the plant cultivated at the Institute of Medicine Plantation of Chongqing, 25 March 2015, Hao Zhou, Si-Rong Yi & Qi Gao QG 784 (Holotype IMC!).

Herbs perennial, evergreen, rhizomatous. Rhizome creeping, subterete, ca. 10 mm in diam., covered with scales, nodes dense. Leaf solitary or paired, 2–4 cm apart; petiole stiff, upright, 12–26(–69) cm long; blade dark green, sublinear, 64– 86(–146) × 1.2–2.8 cm, base cuneate, margin entire, apex acuminate. Peduncle erect or decumbent, 1–3 cm long, with 3–5 bracts, with the two largest bracts at perianth base, broadly ovate. Flowers solitary; perigone widely campanulate to nearly bowl shaped, 6 (rarely 7)-lobed; lobes 6, red-purple, slightly recurved, subequal, triangular-ovate, 8–15 × 7–14 mm, margin pink-white to yellowish-green, with a structure similar to paracorolla at the adjoining lobes, and one keel in the apical portion, which splits into two keels running downwards to the base of the tube; tube purple, ca. 13 × 20 mm. Stamens 6 (rarely 7, matching lobe number), opposite to lobes, inserted at base of the perianth tube; filament 0.5–2 mm long; anthers yellow, elliptic, 3 × 2 mm. Pistil umbrella-like shaped, 8–12 × 15 mm; ovary inconspicuous; style short; stigma white on the upper side and red-purple down side, enlarged, margin deep 6(–7)-incised, lobes 6–7, subequal, 9 mm long, 8 mm wide at base, revolute and bent downwards touching the base of the perigone, located between two stamens. Fruit and seeds unknown. Flowering March–April.

Taxonomic relationships:— It can be distinguished from the other Aspidistra species by its unique umbrella-like pistil with large revolute stigma lobes that bent downwards and touch the base of the perigone. Aspidistra nanchuanensis Tillich (2006: 139) is also found in the same mountain that A. revoluta , but they are differentiated by the perigone (widely campanulate to nearly bowl shaped vs. widely funnel shaped) and the stigma (convex with deep incisions as well as large revolute lobes that bent downwards and touch the base of the perigone vs. flat with small incisions and small lobes that bent downwards and are in contact with the lateral tube wall). The new species is also similar to A. carnosa Tillich (2005: 318) , but can be easily distinguished by the petiole (long vs. sessile), the perigone lobes (slightly recurved vs. erect) and the stigma (umbrella-like shaped, with deep incisions vs. conoid, without incisions). A detailed morphological comparison among A. revoluta , A. nanchuanensis and A. carnosa is shown in Table1.

Etymology:— The name of the new species relates to the large revolute stigma lobes that bent downwards and touch the base of the perigone.

Distribution:— This new species is only known from Jinfoshan Mt. in southern Chongqing, China. It is also currently cultivated at the Institute of Medicine Plantation of Chongqing and the experimental garden of Guangxi Institute of Botany in Guilin, Guangxi.

Pollen morphology:— The pollen grains are subspherical, (25–)28.11(–32.97) × (32.1–)34.28(–36.57) μm and inaperturate ( Fig. 3a ). Verrucous exine sculpture occurs in this species ( Fig. 3b ). So far, the pollen morphology of 35 Aspidistra species has been reported as spherical/subspherical and inaperturate, with three types of exine sculpture, i.e. regulate, verrucous and gemmate exine ( Huang & Hong 1996, Wang et al. 2001a, 2002, Vislobokov et al. 2013, 2014, Gao 2014).

Karyotypic analysis:— The chromosome number of Aspidistra revoluta is counted to be 2 n = 38 ( Fig. 4a ), and the karyotype is formulated as 2 n = 22m + 6sm + 10st ( Fig. 4b ). The first and largest pair of chromosomes is median centromeric. Chromosomes from the II to VIII pairs are large, of which the II and III pairs are submedian centromeric while the others are subterminal centromeric. The IX pair is median-size and submedian centromeric. The remaining chromosomes are smaller and median centromeric ( Fig. 3b ). The average length of chromosome complement is 4.50 μm, and the karyotype asymmetry indexes A 1 and A 2 are respectively 0.37±0.03 and 0.49±0.01.

The majority of the Aspidistra species have a chromosome number of 2 n = 36 or 38, except A. xilinensis Y.Wan & Xiao H.Lu in Wan (1987: 397) (2 n = 72), A. cruciformis Y.Wan & Xiao H.Lu in Wan & Huang (1987: 217) (2 n = 72) and A. sutepensis Larsen (1961: 41) (2 n = 114) ( Wang et al. 2001b, Gao et al. 2015). The karyotypes of Aspidistra species with 2 n = 38 are similar to each other, commonly consisting of one pair of the first and largest pair of m chromosomes, seven (rarely six) large pairs of sm or st chromosomes, one (rarely two) medium-sized pair(s) of sm (and st) and ten small pairs of m or sm chromosomes, except of A. flaviflora Lang & Zhu (1982: 485) with one pair of the first and largest pair of sm chromosomes ( Hong et al. 1986, Li 2004, Qiao et al. 2008, Liu et al. 2011, Liu et al. 2012, Meng & Gao 2014). The constant karyotype also occurs in this new species.

Additional specimen studied (paratype):— CHINA. Chongqing Municipality: Nanchuan District, Jinfoshan Mt., from the plant cultivated in the Institute of Medicine Plantation of Chongqing, 25 March 2015, Hao Zhou, Si-Rong Yi & Qi Gao QG785 (IMC!).

Figures

FIGURE 1. Aspidistra revoluta H.Zhou, S.R.Yi & Q.Gao. a, Habit. b, Flowers. c, Flower in side view. d, Perigone opened in side view, showing stamens and the convex stigma with deep incisions and large lobes that bent downwards and touch perigone base. e, Perigone opened in side view, showing stamens and perigone keels. f, Stigma in upper view. g, Stigma in lower view. h, Stigma in side view.

FIGURE 2. Aspidistra revoluta. a, Plants. b, Flowers. c, Flower in upper view, showing stigma and lobes. d, Flower in side view. e, Flower dissected in side view. f, Perigone opened in side view, showing stamens and the convex stigma with deep incisions and large lobes that bent downwards and touch perigone base. g, Perigone opened in side view, showing stamens and perigone keels. h, Stigma in upper view. i, Stigma in lower view. Scale bar = 1 cm.

FIGURE 3. SEM of pollen morphology in Aspidistra revoluta. a, Pollen grain, scale bar = 8 μm. b, Verrucate exine sculpture, scale bar = 2 μm.

FIGURE 4. Somatic Chromosome at mitotic metaphase in Aspidistra revoluta. a, Photomicrograph of metaphase chromosome of 2n = 38. b, Karyotype formulated as 2n = 22m + 6sm + 10st. Scale bar = 10 μm.