Rhapis excelsa (Thunberg)Henry

Henderson, Andrew, 2016, A revision of Rhapis (Arecaceae), Phytotaxa 258 (2), pp. 137-152 : 142

2. Rhapis excelsa (Thunberg)Henry in Rehder (1930: 153). Chamaerops excelsa Thunberg (1784:130) . Trachycarpus excelsus (Thunberg) Wendland in Gay (1861: 429). Lectotype (designated by Hastings 2003):— JAPAN. No locality, no date, C. Thunberg sheet number 24386 (lectotype UPS n.v., UPS image!)

Rhapis flabelliformis L’Héritier de Brutelle ex Aiton (1789: 473) . Type:—Cultivated plant in J. Gordon’s garden, no date, no collector

(holotype BM n.v., BM image!). Rhapis major Blume (1836: 55) . Type:—No locality, no date, C. Blume s.n. (holotype L n.v.). Rhapis javanica Blume (1836: 56) . Type:— INDONESIA. Java. No locality, no date, C. Blume s.n. (holotype L!). Rhapis divaricata Gagnepain (1937: 158) . Type:— VIETNAM. Tonkin, Sontay, jardin, 31 March 1918, A. Chevalier 37823 (holotype

P!).

Stems 2.3(0.5–4.0) m long, 0.9(0.4–1.4) cm diameter. Leaf ligules acute, soon disintegrating; petioles 29.5(5.7–63.0) cm long, 3.0(1.4–4.6) mm wide at the apex; abaxial hastula usually complete, a low ridge separating petiole apex from costa; segments 8(2–12) per leaf; central segments linear-lanceolate, usually multi-veined, not acuminate, the apices truncate, toothed, 27.6(13.7–39.5) cm long, 3.5(1.7–7.2) cm wide at midpoint, joined at the base, the non-split basal part 4.3(0.8–9.8) cm; lateral segments 24.3(14.0–35.0) cm long, 2.4(1.0–3.8) cm wide at midpoint, the non-split basal part 2.4(0.7–4.7) cm; abaxial surface of segments with minute, brown scales, not indumentose when first exposed. Inflorescences small to large, with the first branch almost as large as the rest of the inflorescence; prophyll and peduncular bract narrow, tubular, not or scarcely overlapping, the inflorescences exerted apically through the bracts on a curved peduncle; rachis 16.9(7.2–24.5) cm long; rachillae not filiform, glabrous; proximal rachilla 9.7(5.7–14.5) cm long, 1.1(0.8–1.6) mm wide; staminate and pistillate flowers sessile; staminate and pistillate corollas with well developed, erect, triangular apical lobes, these swollen internally; filaments keeled; fruits globose, color not recorded, 8.5(7.6–9.3) mm long, 7.0(6.1–7.7) mm diameter, borne on a swollen, persistent perianth.

Distribution and habitat:—Southern China (Guangdong, Hainan, Hong Kong) and northern and central Vietnam ( Fig. 2 ) in lowland rain forest at 211(5–800) m elevation.

Taxonomic notes:— Hastings (2003) designated a Thunberg specimen (sheet number 24386 at UPS), consisting of a single leaf, as lectotype of Rhapis excelsa . However, she then designated the same sheet as lectotype of Rhapis flabelliformis . This is superseded here. Rhapis flabelliformis is considered a synonym of R. excelsa , and although the plate by L’Héritier de Brutelle originally cited by Aiton (1789) has not been found ( Hastings 2003), another specimen was also cited and this is here considered the holotype.

Rhapis major was included as a synonym of R. excelsa by Hastings (2003) and this is followed here. Blume (1836) cited a specimen at L, but this was not found on a recent visit.

Rhapis javanica was included as a synonym of R. humilis by Hastings (2003), but the sterile type specimen, comprising two sheets at L, is clearly identifiable as R. excelsa based on the minute brown scales on the abaxial surface of the segments.

Rhapis divaricata was placed as a synonym of R. excelsa by Hastings (2003), and this is followed here. The type specimen agrees in all character states with R. excelsa .

Rhapis excelsa is one of the most widely and commonly cultivated palms, and has been in cultivation, particularly in Japan, for many years ( Bailey 1939, Yamaguchi & Barry 1974). It is not always clear if specimens are from wild or cultivated plants, but all specimens from Japan are likely to be based on cultivated plants. A specimen (Henry 10173 at NY) from China (Yunnan), identified by Hastings (2003) as R. excelsa is here included in R. humilis .

A specimen (Shiu Ying Hu 12934 from KUN) from a cultivated plant is recorded as having white fruits.

Subspecific variation:— Rhapis excelsa occurs in four areas; southern China, Hainan, northern Vietnam, and central Vietnam. Specimens from northern Vietnam are smaller than those from central Vietnam but not significantly so. Some specimens from Hong Kong are considerably smaller than others, but other ones from there are the more usual size. It is not clear if some of these smaller specimens are from cultivated plants or not.

Figures

FIGURE 2. Distribution maps of Rhapis evansii, R. excelsa, R. gracilis, and R. humilis.