Helonias leucantha (Koidz.) Tanaka (1998a: 107)

Tanaka, Noriyuki, 2019, Taxonomy, evolution and phylogeography of the genus Helonias (Melanthiaceae) revisited, Phytotaxa 390 (1), pp. 448-450 : 448-450

publication ID

https://doi.org/ 10.11646/phytotaxa.390.1.1

persistent identifier

https://treatment.plazi.org/id/03E5713A-FF88-9149-4099-FA1FD68C3724

treatment provided by

Felipe

scientific name

Helonias leucantha (Koidz.) Tanaka (1998a: 107)
status

 

8. Helonias leucantha (Koidz.) Tanaka (1998a: 107) View in CoL ( Figs. 18–20 View FIGURE 18 View FIGURE 19 View FIGURE 20 ).

Sugerokia leucantha Koidzumi (1937: 46) View in CoL . Type:― JAPAN. Loochoo [Ryûkyû, Okinawa Pref. ]. Insula Utchina View in CoL [Okinawa I.]; Kunchan, Hetona, Abagawa, Yonagawa, Katena, Taniwadake, Ajagawa, T. Sonohara (Syntype in KYO; photo of a syntype from Abagawa in TNS-320909!). ≡ Heloniopsis leucantha Koidzumi (1937: 46) View in CoL . ≡ Hexonix leucantha (Koidz.) Wang & Tang (1949: 114) View in CoL .

Japanese name:―Ô-shiro-shôjôbakama ( Koidzumi 1937).

Description:―Rhizome subcylindrical, stout, to 2 cm long, 1.5 cm in diam. Roots filiform, ca. 1 mm in diam., white. Leaves persistent for 1–2 years, narrowly oblanceolate or spatulate, 10–31 cm long, 2–4 cm wide, base cuneate, apex acuminate or acute, with apiculus 0.7–2 mm long, somewhat thick in texture, glossy, abaxial midvein slightly raised, adaxially veins indistinct. Flowering stem to 27 cm long (incl. inflorescence); peduncle fistular, 5–25 cm long, 3–8 mm in diam. in middle, light green; scale-like leaves on peduncle usually 5–12 (excl. basal ones), narrowly lanceolate or subulate, to 3.8 cm long, becoming smaller upward, acute, involute, whitish or pale green, submembranous; inflorescence a short compact raceme, rachis to ca. 3.5 cm long, often slightly drooping distally; pedicels decurved at anthesis, 6-ribbed, to 11 mm long at anthesis, to 20 mm long in fruit, white, ebracteate. Flowers 4–36, often secund, nodding, (tubular-)campanulate, odorless or sometimes faintly fragrant, protogynous. Tepals 6, narrowly oblong or narrowly elliptic-oblong, 9.5–16.5 mm long, 2–6.5 mm wide, apex acute, recurved distally, silky white, sometimes pale lilaceous, turning pale pink with progression of anthesis, adaxially canaliculate toward base, proximal submarginal portions raised, proximal margins narrowly and slightly revolute, often slightly imbricate, basal nectary saccate adaxially; abaxial base slightly gibbous; base of tepal affixed to receptacle (apex of pedicel) for ca. 1–1.2 mm in length. Stamens 6, usually exserted beyond tepals; filaments from adaxial rim of nectary of opposing tepal, filiform-subulate, 4.4–18.5 mm long, base slightly dilated and complanate, white or pale lilaceous; anthers narrowly ovoid or ellipsoid, 1–2.5(–3.3) mm long, base sagittate, apex obtuse, virtually bilocular, with vestigial apical confluence between thecae, basifixed adaxially, extrorse, pale to dark (bluish) purple; pollen whitish. Pistil 1, usually exceeding stamens and tepals; ovary globose or obovoid, slightly trilobed, 2.5–3 mm long, 3–3.7 mm across, apex emarginate-concave, yellowish green, dull dark purple, or dull dark purplish green, often with short stipe (gynophore) to 0.6 mm long; style terete, strict, 4.5–14.5 mm long, pale purple or purplish pink; stigma densely papillulate, discoid, depressed capitate or hemispheric, often obtusely trigonous or slightly trilobed, 1.3–2.2 mm across, 0.7–1.2 mm thick, white, light purple or dark purplish pink; ovules numerous, multiseriate on central axile placentae. Capsules obpyramidal, obcordate in lateral aspect, apex depressed in center, tripartite, 8–9 mm long, 8–12 mm across, lobes mitriform, divergently protruding subdistally. Seeds sublinear or narrowly fusiform, testa whitish, proximally caudate, distally acicular, 4.5–5.8 mm long, 0.25–0.3 mm wide; body of seed oblong-fusiform, 1–1.5 mm long, 0.2 mm wide, (dark) brown.

Additional specimens examined (see also Tanaka 1998a):― JAPAN. Okinawa. Okinawa Pref. Okinawa Isl. : Kunigami-gun, Ôgimi-son, 16 August 1951, T. Amano 6331 (TNS-129705); Haneji-son, Makiya-ku, 29 November 1954, M. Nakamine 322 (RYU-41828; TNS-116547, 116548). Iriomote Isl.: Urauchi Riv., 150 m, 13 June 1971, T. Yamazaki (TI). Ishigaki Isl.: August 1958, Y. Niiro (RYU-19301).

Distribution:―SW Japan, Nansei Islands (incl. Ryûkyû Isl.). Kagoshima Pref.: Tokunoshima Isl. ( Hatusima 1986). Okinawa Pref. : N Okinawa, Ishigaki, and Iriomote Isl. ( Fig. 29-L View FIGURE29 ).

Habitat:―Shady moist rocks and slopes near or along streams in forests at elevations 120–400 m.

Conservation status:―Assessed by the Environment Agency of Japan (2000) as EN on the basis of the criterion E in IUCN (1994). Deforestation and dam construction are regarded as main threats to the species.

Flowering:―Late December–mid March.

Ripening:―April–May.

Remarks:― Helonias leucantha is most closely allied to H. umbellata (e.g. Figs. 21 View FIGURE 21 , 22 View FIGURE 22 ), from which it differs by its usually larger leaves ( Fig. 18D View FIGURE 18 ), nodding tubular-campanulate flowers ( Figs. 18A–D View FIGURE 18 , 19A View FIGURE 19 ), narrowly oblong-elliptic tepals imbricate proximally ( Figs. 19A, D View FIGURE 19 ), and somewhat smaller anthers ( Fig. 19A, D View FIGURE 19 ). The tepals are usually white, but turn pale pink or purplish pink as flowering proceeds. Flowering of Helonias leucantha slightly precedes ser. Heloniopsis , and this may be due to the warm, maritime climate of the Nansei Islands where it occurs. Cernuous, campanulate, often scarcely fragrant flowers of Helonias leucantha are supposed to have originated in response to pollinators ( Tanaka 1997d).

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Helonias

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Sugerokia

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Apidae

Genus

Nomada

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Heloniopsis

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Hexonix

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Helonias

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Helonias

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Helonias

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Apidae

Genus

Nomada

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hymenoptera

Family

Apidae

Genus

Nomada

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Liliales

Family

Melanthiaceae

Genus

Helonias

Loc

Helonias leucantha (Koidz.) Tanaka (1998a: 107)

Tanaka, Noriyuki 2019
2019
Loc

Sugerokia leucantha

Wang F. T. & Tang, T. 1949: )
Koidzumi, G. 1937: )
Koidzumi, G. 1937: )
1937
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