Elaeocarpus polystachyus Wall. ex Müll. Berol.
by Phoon Sook Ngoh
Elaeocarpus polystachyus Wall. ex Müll. Berol.
by Phoon Sook Ngoh

Elaeocarpus polystachyus is a medium-sized rainforest tree to 23 m tall that occurs from lowland to hill dipterocarp forest to 840 m altitude, including peat swamp and coastal forest, but rarely up to montane forest. This sun-loving species usually grows in small populations, on hill slopes and ridges but is more common in secondary forest than in primary forest.

The outer bark of E. polystachyus is grey-brown with pale brown inner bark and cream sapwood. The stipules are narrowly triangular, dark brown or black, and sometimes persist even after leaf maturity. The simple leaves are spirally arranged and loosely grouped towards the twig tips. The long petioles, which grow up to 18 cm long and are kneed at both ends, are one of the diagnostic characters for E. polystachyus. The leaf blades are elliptic to ovate, usually to 19.5 × 10 cm, with 6–12 pairs of lateral veins. The hairy racemose inflorescences bear many brownish yellow flowers with sometimes as many as 38 flowers per inflorescence. The flowers are 4-merous, but mutation in flower part number is recorded in two specimens: one from Slim Hills Forest Reserve, Perak (Whitmore FRI 717) has 5-merous flowers, and the other from Bukit Timah, Singapore (Samsuri Ahmad SA 1353) has a mixture of 4- and 5-merous flowers. The annular disc is hairy and weakly-developed, thus is structurally less obvious. The stamens are numerous, between 50–65 per flower, and are densely-arranged in multiple tiers; they are brown turning blackish brown after anthesis. The filaments are short, between 0.5–1 mm long. The anthers are a little longer, between 1.5–2 mm long, and are not awned. The 2-locular ovary is densely covered by yellowish brown hairs and each locule contains 10–12 ovules. The oblong or ellipsoid fruits are green and hairy when young, turn glabrescent and once were recorded as yellow when mature (Suppiah FRI 11360) instead of blue as in most Elaeocarpus fruits. Often only one seed is developed in each fruit and the seed is enclosed within a hard stone that develops from the inner mesocarp. The embryo is curved and the endosperm is ruminate.

Elaeocarpus polystachyus is endemic to Peninsular Malaysia and Singapore and is locally abundant in Bukit Timah Nature Reserve, Singapore, but becomes less common from Johor northwards to Kelantan and Perak. The species belongs to the Polystachyus group and the latter consists of five other West Malesian endemics, i.e. E. cupreus Merr., E. clementis Merr., E. multinervosus R.Knuth, E. polyanthus Ridl. and E. integripetalus Miq. Members of this group share high morphological similarities, particularly their floral characters, such as petals that are entire or very shallowly fimbriate with up to 6 divisions, the numerous stamens (35–80 per flower) densely-arranged in multiple tiers and anthers that are not awned (Coode 1996).

QR Code
Scan QR code for mobile experience

Other articles

Phaenicophaeus curvirostris (Shaw, 1810)

Nurfahana Binti Mo`in & Ms. Nur Aina Amira Binti Mahyudin   •   30 Nov 2023   •   110 views

Chrysopelea paradisi (Boie, 1827)

Ms. Noor Faradiana Binti Md Fauzi & Mr. Mohammad Shahfiz Azman   •   15 Nov 2023   •   547 views

Piper sarmentosum Roxb. (Piperaceae)

Ms. Nur Asma Fatin Umirah Binti Mahmud, Mrs. Sarah Nabila Binti Rosli & Ms. Nurfarhana Hizan Binti Hijas   •   31 Oct 2023   •   637 views

Begonia herveyana King

Mr. Tan Kok Kiat   •   16 Oct 2023   •   808 views

Pangium edule Reinw. (Achariaceae)

Mrs. Norzielawati Salleh   •   29 Sep 2023   •   427 views
Today, there are less than 200 Malayan tigers left in our country.
#SaveOurMalayanTiger. Visit
Malaysia Biodiversity Information System (MyBIS)   by   Malaysia Biodiversity Centre (MBC)

Copyright © 2023, Malaysia Biodiversity Centre (MBC), Ministry of Natural Resources, Environment and Climate Change (NRECC). All rights reserved. DISCLAIMER - The Malaysian Government, Ministry of Natural Resources, Environment and Climate Change (NRECC), Malaysia Biodiversity Centre (MBC) and Forest Research Institute Malaysia (FRIM) shall not be liable for any loss or damage caused by the usage of any information obtained from this website. By entering this site, you acknowledge and agree that no portion of this site, including but not limited to names, logos, trademarks, patents, sound, graphics, charts, text, audio, video, information or images are either MyBIS property or the property permitted by third-party and shall not be used without prior written approval from the owner(s).
Best viewed using latest Mozila Firefox, Google Chrome and Internet Explorer 10 with Resolution 1024 x 768px or above. Version 2.0 / 2016
Website Citation: MyBIS (2023). Malaysia Biodiversity Information System. Published on the Internet, Ministry of Natural Resources, Environment and Climate Change, Malaysia Biodiversity Centre & Forest Research Institute Malaysia. [Retrieved 04 December 2023].