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 c. 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, and abundant caducous dark indumentum, spines shorter and sparser on distal sheaths; ocrea absent; knee absent; flagellum absent; petiole in distal leaves very short or absent, not exceeding c. 3 cm long, up to 2.5 cm wide; 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 x 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 the topmost many 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 0.20 cm diam., with a short beak to 0.2 x 0.2 cm and covered in c. 35 vertical rows of dull brown scales with smooth margins and non-spiny tips. Seed rounded, basally somewhat flattened, c. 1.2 cm diam.; endosperm homogeneous.
We follow Henderson (2009) in including P. 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 summarised as follows:
1. Bracts subtending male rachillae 19–40 mm long, male rachillae 8–19 mm long; bracts subtending female rachillae 25–40 mm long, female rachillae 12–20 mm long; mature fruit to 20 mm diam. P. pierreana
1. Bracts subtending male rachillae 40–50 mm long, male rachillae 25–35 mm long; bracts subtending female rachillae 40–50 mm long, female rachillae >20 mm long; mature fruit to 23 mm diam. P. kerriana
The possibility for overlap in all these characters suggests that P. 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.
Global — South China, Vietnam, Laos, Cambodia (type), Myanmar.
Thailand — NORTHERN: Chiang Mai, Tak; EASTERN: Nakhon Ratchasima; CENTRAL: Saraburi, Nakhon Nayok; PENINSULAR: Ranong.
Evergreen forest, often in light gaps, river banks and roadsides, to 1200 m altitude.
Produces a coarse cane of little value; inflorescence branches can be used as ornaments.