Cremanthodium gracillimum Smith (1917: 27)

Wang, Long, 2020, Resurrection of Cremanthodium gracillimum and C. wardii (Asteraceae, Senecioneae), with notes on the genus in Myanmar, Phytotaxa 446 (3), pp. 183-198 : 183-185

1. Cremanthodium gracillimum Smith (1917: 27) . Figs. 1A, B , 2 .

Type:— MYANMAR. Kachin: ridge of Naung Chaung-Nmai divide, on moss-covered rocks and on granite cliffs in shade of dwarf Rhododendron , 15 July 1914, F. Kingdon-Ward 1783 (holotype E!). Fig. 1A .

Perennial herbs, 15−20 cm tall. Stems solitary or 2, erect, 1−1.5 mm in diam. at base, proximally glabrous, distally sparsely yellowish arachnoid. Basal leaves 2−4, petiolate; petiole 10−14 cm long, slender, base sheathed; leaf blade reniform, 1.1−1.8 cm long, 1.3−2.8 cm wide, both surfaces initially thinly arachnoid, base cordate, margin regularly denticulate, apex shallowly mucronulate; palmate veins prominent abaxially. Proximal stem leaf absent or 1, petiolate, base slightly sheathed; leaf blade reniform, smaller than basal leaves. Distal stem leaf absent or 1, sessile, linear, bracteal. Capitula solitary, nodding. Involucre campanulate, 1.1−1.3 cm high, 1.8−2.9 cm in diam., outside glabrescent; phyllaries 12−15, nearly in 1 row, narrowly oblong to oblong, 1.5−3 mm wide, apex acute, margin narrowly to broadly membranous, apex acute; bracts few, subulate, 2−3 mm long, ca. 1 mm wide, apex acute, subtending the head. Ray florets dull crimson, 7−12; lamina broadly oblanceolate, 1.9−2.5 cm long, 0.6−0.8 cm wide, apex truncate, deeply 3- lobed; tube ca. 5 mm long. Tubular florets numerous, purplish red, 8 mm long; tube 2 mm long; limb 6 mm long; style 1 cm long. Achenes 2 mm long, obovoid. Pappus dirty white, ca. 7 mm long, as long as tubular corolla.

Distribution and habitat:—Known only from northeastern Myanmar ( Fig. 2 ), growing on granite cliffs at altitudes of 3600−4200 m a.s.l.

Phenology:—Flowering in July.

Additional specimens examined:— MYANMAR. Kachin: Imaw Bum, F. Kingdon-Ward 3361 (E).

Notes:— Smith (1917) described Cremanthodium gracillimum on the basis of a single collection, F. Kingdon-Ward 1783 (E; Fig. 1A ), from northeastern Myanmar. In the protologue, the author stated that it was similar to C. decaisnei Clarke (1876: 168) , but differed by the very slender habit and the crimson ray florets. Good (1929), Koyama (1968) and Kress et al. (2003) all recognized C. gracillimum as a separate species, and Good (1929) further referred to it another collection, F. Kingdon-Ward 3361 (E; Fig. 1B ), from northeastern Myanmar. Liu (1989), however, pointed out that C. gracillimum , with the ray florets first purple and then becoming white and the tubular florets 10−15 mm long, was not essentially different from C. rhodocephalum Diels (1912: 190) . He thus reduced C. gracillimum to the synonymy of C. rhodocephalum , a treatment accepted by Min (2004) and Liu & Illarionova (2011). It seems that Liu (1989) did not see any material of C. gracillimum but based his treatment only on the original description of this species.

Comparison of herbarium specimens (including type material) of Cremanthodium gracillimum ( Fig.1A, B ) and C. rhodocephalum ( Fig. 1C, D ), together with observations on several populations of the latter species in the field ( Figs. 3 , 4 ), indicate that the two species are readily distinguishable from each other and that the specific status of the former should be reinstated. Cremanthodium gracillimum differs immediately from C. rhodocephalum by the presence (vs. absence) of a basal leaf rosette, the fewer stem leaves (absent or 1−2 vs. 5−14), and the presence (vs. absence) of several subulate bracts below the involucres ( Fig. 1A, B ). Morphologically C. gracillimum most closely resembles C. thomsonii Clarke (1876: 169) in the slender habit, but differs by the dull crimson (vs. yellow) ray florets and the presence (vs. absence) of several subulate bracts below the involucres. A detailed comparison of C. gracillimum , C. rhodocephalum and C. thomsonii is given in Table 1.

Figures

FIGURE 1. Specimens of Cremanthodium gracillimum (A, B) and C. rhodocephalum (C, D). A. Myanmar, Kachin, Naung Chaung-Nmai divide, F. Kingdon-Ward 1783 (E; holotype). B. Myanmar, Kachin, Imaw Bum, F. Kingdon-Ward 3361 (E). C. China, Yunnan, Lijiang, G. Forrest 2665 (E; holotype). D. Same locality, G. Forrest 2665 (BM; isotype).

FIGURE 2. Distribution of Cremanthodium gracillimum (●).

FIGURE 3. Cremanthodium rhodocephalum in the wild (China, Yunnan, Shangri-la). A. Habitat. B, C. Habit. Photographs: Long Wang.

FIGURE 4. Cremanthodium rhodocephalum in the wild (China, Yunnan, Shangri-la).A. Portion of stem. B. Leaf blade (adaxial surface). C. Leaf blade (abaxial surface). D. Capitulum (top view). E. Capitulum (back view). F. Capitulum (side view), with some ray florets removed. G. Outer phyllaries (abaxial surface). H. Inner phyllaries (abaxial surface). I. Ray florets. J. Tubular florets. Photographs: Long Wang.