Chrysosplenium fallax Koldaeva, 2021

Koldaeva, Marina N., 2021, Chrysosplenium fallax (Saxifragaceae), a new species from the Russian Far East, Phytotaxa 491 (1), pp. 35-46 : 39-43

Chrysosplenium fallax Koldaeva , sp. nov. ( Fig. 1–4 ).

Diagnosis:— Unlike C. villosum , C. fallax forms a plagiotropic rhizome with long internodes and specialized underground stolons. The vegetative shoots do not take root by the end of the growing season, and are with acervate leaves on the top. Chrysosplenium fallax differs from C. pilosum by vegetative shoots lacking branching in the distal part, with larger acervate leaves on the top, which are pubescent on the abaxial side of the leaf blade.

Type: — RUSSIAN FEDERATION. Primorsky Krai, Vladivostoksky Urban Okrug, Muravyev-Amursky Peninsula, Malaya Pionerskaya River valley , edge of a coniferous-broadleaved forest, moist habitat, 12 May 2017, M.N. Koldaeva 0115 (holotype LE!, isotypes LE!, VLA!, VBGI!) .

Description of the new species:—Perennial herb, pulpy, pubescent with long, white hairs, reddish when dry. Leaves opposite. Stems and early leaves are reddish below. Rhizome 1.2–5 cm long, underground, plagiotropic, with 2–5 elongated internodes. Flowering stem single, erect, 14–20(–24) cm tall, middle part sparsely pubescent, and base and apical part almost glabrous. Cauline leaves in 2–4 pairs. Leaf blade subflabellate or flabellate-rounded, 0.3–1.3 × 0.4–1.9 cm, base cuneate or broadly cuneate, adaxial surface glabrous, abaxial surface glabrous or with single hairs along veins at base, often with red specks; margin ciliate, with 5–7–9 smoothed-serrated crenates; petiole 0.3–0.9 cm in length. Cymes compact, 6–16 flowered, surrounded by large, greenish-yellow bracts. Inflorescence branches and bracteal petioles with solitary long hairs. Flowers goblet-shaped, yellow, sometimes with red specks; pedicels short (0.8–3 mm). Sepals 4, erect, convex outside, with the tip slightly bent outward; external almost rounded 2.2 × 2.1 mm; internal ovoid 1.8 × 1.5 mm, shorter than external ones. Stamens 8, equal to calyx; anthers yellow. Ovary subsuperior. Styles erect, slightly divergent. Nectary not prominent, green. Capsule 6–8 mm, ca. 2–2.5 times longer than calyx. Carpels 2, slightly unequal, divergent, arcuately curved. Seeds suborbicular, 0.7–0.8 × 0.6–0.7 mm, brown, minutely papillose, with 18–23 longitudinal rows of large, densely located tubercles. Tubercles almost cylindrical, with one, rarely two papillae. Vegetative shoots above-ground (sterile) and underground (stolons). Above-ground shoots orthotropic (axial and lateral), prostrate and repent, stolon-like, pubescent with long hairs, most densely aggregated at apical part. Orthotropic shoots not evenly leafed; leaves highly unequal, with largest ones acervate to resemble a rosette at the apex but without forming a true rosette; apical part not rooted. Axial sterile shoots up to 21 cm long, with branches or non-branching. Leaves 4–9(–11) pairs; distal 2–3 pairs largest, 2.1–5.6 × 2.0– 3.7 cm (except the uppermost one), with short internodes (0.2–0.5 cm); blade rounded, rounded-ovate or elliptical; base cuneate; margin undulate-crenate, crenate-sinuate or almost smooth, ciliate, with 5–7 crenates on each side. Lateral sterile shoots up to 16 cm long, with basal internode elongated; leaves (1–)2–3 pairs, acervate to resemble a rosette at the apex. Pubescence of leaf abaxial side along main veins appears on 1 st or 2 nd pairs of lateral shoots or in 2 nd to 5 th pairs of axial shoots; in upper pairs, pubescence becomes denser. Blade adaxial side glabrous or with solitary hairs at the periphery, sometimes with silvery dots. Petioles sparsely pilose on both sides. Above-ground prostrate shoots with rising apex or flagelliform, evenly leafed; leaves highly unequal, with largest ones located in the third quarter from shoot base. Repent stolon-like shoots 1–2, evenly leafed; leaves 5–6 pairs, similar, small. Underground stolons 1–3(–4), up to 48 cm long, 1.5–2 mm in diameter, unbranched or weakly branched in distal part, white. An approximately 10-cm-long distal portion of stolon remains by the end of the growing season. In the population, most shoots are sterile axial; flowering shoots are single.

Distribution:— Chrysosplenium fallax is known only from southern Primorsky Krai, Russian Federation ( Fig. 5 ). It is most frequently found in Shkotovsky District, as well as in Ussuriysky and Vladivostoksky (except islands) Urban Okrugs. In other areas, where plants of this species were collected, it is rare and has populations on small areas and with few individuals.

Habitat:—The new species grows in broad-leaved forests on moist and damp parts of gentle slopes, along river valleys and streams, at an elevation of 20–380 m.

Phenology:—The flowering season of C. fallax is the first and second ten days of May; the fruiting season, the first and second ten days of June.

Etymology:—The name of this species means that in its different phenological states C. fallax becomes similar to one species of Chrysosplenium and then to another, which previously led to the misidentification of its specimens and confusion with other species, and, therefore, it has long remained undiscovered.

Relationships:— Chrysosplenium fallax belongs to the ser. Pilosa , being closest to C. pilosum and C. villosum . A list of differences from the species for which it is usually mistaken are presented in Table 2.

Figures

FIGURE 1. Chrysosplenium fallax. A. Habitat. B. Flowering plant.

FIGURE 2. Chrysosplenium fallax. A–B. Branching of a generative plant. C. Structure of generative and vegetative plants. D. Structure of the shoot system. E. A vegetative plant with slanting axial shoot: (a) generative shoot; (b) lateral above-ground vegetative shoots; (c) axial above-ground vegetative shoot; (d) rhizome; (e) underground stolons; (f) above-ground repent stolon-like shoot.

FIGURE 3. Axial vegetative shoot of Chrysosplenium fallax. A. Apical part of a shoot at the beginning of growth. B. Apical part of a growing shoot. C. Apical part of a shoot at the end of growth. D. Shoot in the late growing season. E. Prostrate shoot with rising apex.

FIGURE 4. Chrysosplenium fallax.A. Flower. B. Inflorescence. C. Capsules (side view). D. Capsules (top view). E. Seed. F. Seed surface structure.

FIGURE 5. Distribution of Chrysosplenium fallax. Red dots indicate localities of herbarium specimens; green dots are localities of author’s specimens.