Volume 11 > Part 3 > Year 2013 > Page 477 > Arecaceae > Plectocomia

3. Plectocomia pierreana Becc.wfo-0000275175

Webbia 3: 236. 1910; Evans et al., A Field Guide to the Rattans of Lao PDR: 76. 2001. Fig. 23.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Moderately robust, clustering rattan. Stems climbing to 35 m long, without sheaths 0.5–4 cm diam., with sheaths 1–9 cm diam., internodes up to ca 30 cm long, the stem generally very slender near the ground, much more robust distally, particularly just before flowering. Leaves cirrate; sheaths mid green, armed with scattered, golden, needle-like spines, 1–2 cm long, sometimes arranged in horizontal combs of no more than 5 spines, abundant caducous dark indumentum, spines shorter, sparser on distal sheaths; ocrea absent; knee absent; flagellum absent; petiole in distal leaves very short or absent, not exceeding ca 3 by up to 2.5 cm; rachis to 3 m long; cirrus to 1 m long; leaflets up to 40 on each side of the rachis, irregularly arranged in groups and fanned within the groups, the largest 40–55 by 3.5–4 cm, adaxially shiny dark green, abaxially with a fugacious layer of white indumentum, usually conspicuous on newly emerged leaves, sometimes long persistent, the leaflets generally lacking bristles. Inflorescences male and female superficially similar, produced simultaneously from many topmost nodes (up to 15 or more) the basalmost to 1.5 m long, decreasing in length towards the stem tip, the longest with up to 15 pendulous first order branches; first order branches bearing conspicuous pale yellowish-green, reddish-brown tipped bracts, tubular at first, soon splitting along their length, each subtending a short rachilla, bracts in male inflorescences 1.9–4 cm long, male rachillae 0.8–1.9 cm long, bracts in female inflorescence 2.5–4 cm long, female rachillae 1.2–2 cm long, all bracts becoming chestnut brown with age and persisting to fruiting. Fruit at maturity rounded, to 2 cm diam., with a short beak to 0.2 by 0.2 cm and covered in ca 35 vertical rows of dull brown scales with smooth margins and non-spiny tips. Seed rounded, basally somewhat flattened, ca 1.2 cm diam.; endosperm homogeneous.

Thailand : NORTHERN: Chiang Mai, Tak; EASTERN: Nakhon Ratchasima; CENTRAL: Saraburi, Nakhon Nayok; PENINSULAR: Ranong.

Distribution : South China, Vietnam, Laos, Cambodia (type), Myanmar.

Ecology : Evergreen forests, often in light gaps, river banks and roadsides, to 1,200 m alt.

Vernacular : Not recorded.

Uses: Produces a coarse cane of little value; inflorescence branches can be used as ornaments.

Conservation Status: Not threatened.

Notes: We follow Henderson (2009) in including Plectocomia kerriana in synonymy with P. pierreana. The former is still known only from the type collection from Doi Suthep. Evans et al. (2002) discussed the differences between the two species in detail and they can be summarized as follows:

1. Bracts subtending male rachillae 1.9–4 cm long, male rachillae 0.8–1.9 cm long; bracts subtending female rachillae 2.5–4 cm long, female rachillae 1.2–2 cm long; mature fruit to 2 cm diam. Plectocomia pierreana

1. Bracts subtending male rachillae 4–5 cm long, male rachillae 2.5–3.5 cm long; bracts subtending female rachillae 4–5 cm long, female rachillae >2 cm long; mature fruit to 2.3 cm diam. Plectocomia kerriana

The possibility for overlap in all these characters suggests that Plectocomia kerriana may be merely a very robust form of P. pierreana. In the past leaflet indumentum was regarded as an important distinguishing character but we now know that this feature varies not only within and between populations but also between juvenile and adult stems of the same individual, where clustering.