Pinanga declinata 學問
Stems clustered, to 5 m tall, 3–5.5 cm diameter, densely covered with reddish-brown scales. Leaves 5–7; sheaths closed, forming crownshafts, 43–57 cm long, yellowish with reddish-brown scales; petioles 19–52 cm long, yellowish; rachis 105–111 cm long; pinnae linear, contracted at the bases, 20–21 per side of rachis, middle pinna 38–69 cm long, 3.5–5 cm wide at the middle, apical pinna 6.5–21 cm long, 3.5–5 cm wide at the middle, lobed; veins prominent adaxially. Inflorescences infrafoliar, spreading; peduncles 2.5–3 cm long, 0.5–1 wide; prophylls 14–17 cm long; rachis 3.5–4 cm long; rachillae 4–8, 15–22 cm long, glabrous, triangular in cross-section, with one flat surface with no triads, the triads arranged along the other two surfaces; triads distichously arranged, occasionally spirally arranged; staminate flowers not known; pistillate flowers 2 mm long; sepals 3, 2 mm long, imbricate, the margins ciliate, acuminate; petals 3, 2 mm long, imbricate, the margins ciliate, not acuminate; ovary 2.5 mm long; fruits 1.5–2 cm long, 0.5–0.7 cm diameter, narrowly ellipsoid, color unknown; endosperm ruminate.
A new species described in 2008 form south-central to south-eastern Vietnam. Pinanga declinata is similar to P. sylvestris but differs in its yellow (versus green) sheaths and petioles and pinnae which are strongly contracted at the bases. It can be distinguished from the similar P. annamensis by its 20–21 linear (versus 8–12 falcate) pinnae which are contracted at the bases (versus not contracted), and spreading (versus pendulous) rachillae.