Umbellatae N.Tanaka, 2019

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

Ser. 1. Umbellatae N.Tanaka , ser. nov.

Type:― Helonias umbellata (Baker) N.Tanaka (≡ Heloniopsis umbellata Baker ).

Japanese name:―Hime-shôjôbakama retsu.

Species included:―3; H. kawanoi , H. leucantha , H. umbellata .

Description:―Leaves thin to moderately thick, persisting for 1 to 2 years, margins entire or sometimes minutely undulate, apex prominently apiculate. Inflorescences racemose or (sub)umbellate; pedicels ebracteate, or bracteate

( H. kawanoi ). Flowers 1–many, funnelform or campanulate, nodding, or variously oriented, fragrant or sometimes odorless. Tepals pink or white, usually free to base, adaxial surface slightly to prominently canaliculate toward base, proximal submarginal portions more or less raised (or ridged), occasionally slightly connate with adjoining tepals ( H. umbellata ), nectary at adaxial base slightly or moderately concave, abaxial basal part slightly or moderately gibbous. Filaments free to base, positioned at or close to adaxial rim of nectary of opposing tepal. Anthers affixed adaxially to filament at or close to base of connective (i.e. basifixed or somewhat dorsi-basifixed), apparently bilocular with rudimentary apical confluence between thecae. Stigma discoid, sometimes slightly trilobed. Flowering January to March or late summer to autumn ( H. kawanoi ).

Distribution:―SW Japan (Nansei Isl., incl. Ryukyus), Taiwan ( Fig. 29 -Ka, -L, -U, 31-3, 32-3).

Remarks:―All the members of Helonias ser. Umbellatae are insular (e.g. Fig. 29 ), implying that they are relict descendants of ancestral populations that were once more widespread over land now under the sea. The seeds of Helonias can be dispersed by wind, but it is quite improbable that they disperse far beyond a vast sea or strait. Several characters of the three species of H. ser. Umbellatae are compared in Table 8; a key to distinguish the species is below.

Identification key to the species of H. ser. Umbellatae

1.

-.

2.

Figures

FIGURE29.Distributionofsixspeciesbelongingtotwoseriesofsubsect.HeloniopsisinEAsia.B:Heloniasbreviscapa.Ka:H.kawanoi.Ko: H.koreana.L:H.leucantha.O:H.orientalis.U:H.umbellata.Ser.UmbellataecomprisesKa,LandU.Ser.HeloniopsisconsistsofB,KoandO.