Explore the Beauty of Elaeocarpus rugosus Flowers: A Guide

The Elaeocarpus rugosus is a tree species belonging to the Elaeocarpaceae family, found within the genus Elaeocarpus. The tree features robust, cylindrical twigs with noticeable leaf and flower stalk scars.

Its leaves are either leathery or thinly leathery, clustered at the tip of the branches, and come in various shapes: inverted egg-shaped to lanceolate, violin-shaped, inverted egg-shaped to elliptical.

With 16-18 lateral veins, the upper surface has flattened central and lateral veins, and a conspicuous network of veins, while on the underside, the central, lateral, and network veins are all prominent.

The leaf stalks are bent at the top like a bent knee. The dense, racemose inflorescences grow in the axils of both fallen and growing leaves, with each bearing approximately 8-10 large flowers.

Elaeocarpus rugosus

The flower buds, pedicels, and inflorescence stalks are densely covered with rust-colored tomentum.

The flower buds are oblong with a sharp tip and a rounded base; sepals number 5-6, hairy on the outside and glabrous on the inside; petals also 5-6 with 15-20 small lobes; there are 45-51 stamens; the glandular disk is 5-lobed with each lobe bifurcated and hairy; the ovary is densely tomentose, the style is glabrous in the upper part and slightly longer than the stamens.

The drupe is ellipsoid, the outer skin is tomentose, and the inner skin has prominent nodular protrusions, with the pit being flattened and having two distinct edges.

This species is distributed across China, India, Myanmar, Bangladesh, Thailand, and the Malay Peninsula, thriving in the evergreen broadleaf forests of valleys and ravines at elevations of 500-800 meters.

In South China, the Rough-fruited Elaeocarpus is an important ornamental tree. It is commonly planted in groups on lawns, at intersections, and along forest edges in gardens.

It also serves as an excellent street tree and plays an important role in scenic forestry. Additionally, it is used as a landscaping tree in industrial areas.

The Rough-fruited Elaeocarpus is listed on the IUCN Red List of Threatened Species (version 3.1, 1998) as Vulnerable (VU).

I. Morphological Characteristics

The tree reaches up to 30 meters in height. Its twigs are robust, cylindrical, 6-11 millimeters thick, with distinct leaf scars and peduncle marks, covered with rust-brown tomentum, and are brown in color.

The leaves are leathery or thinly leathery, clustered at the tips of branches, varying in shape from inverted ovate-lanceolate, viol-shaped, inverted ovate to inverted ovate-elliptical, measuring (14-)18-30(-45) centimeters in length and 6-11(-16) centimeters in width.

The leaf tips are abruptly pointed, rounded, or slightly indented, narrowing from two-thirds of the way toward the base, which is cuneate in shape, with margins featuring shallow, obtuse teeth.

The leaf surface is very sparsely hairy along the midrib, and the underside bears extremely sparse soft hairs; with 16-18 lateral veins, the veins on the surface are flush and the reticulate veins are conspicuous, whereas on the underside, the midrib, lateral veins, and net veins are all prominent.

The leaf stalks are kneed at the top, 1-2.6 centimeters long and 3 millimeters thick, flat on the top and round underneath, initially covered with rust-yellow hairs, later becoming bare.

The panicle inflorescence is borne in the axils of both fallen and growing leaves, dense, 4-12 centimeters in length, with large flowers, about 8-10 in number; densely covered with rust-colored tomentum on flower buds, pedicels, and peduncles, the pedicels are 9-18 millimeters long; flower buds are oblong, acute at the tip, and rounded at the base, 10-14 millimeters in length; there are 5-6 sepals, 11.5-14.5 millimeters long, hairy on the outside and hairless on the inside; the petals are also 5-6, 13-15 millimeters in length and 8 millimeters wide, the tips are torn to about a fifth, with 15-20 small lobes, densely covered with rust-yellow tomentum on the outside and tomentose on the inside, with ciliate margins; there are 45-51 stamens, anthers 3.5-4 millimeters long with a 4-4.5 millimeter awn at the tip, and filaments 2-2.5 millimeters long; the staminal disc is pentagonally lobed, small, each lobe bifurcated, and hairy; the ovary is densely tomentose, bicameral, with numerous ovules in each chamber, the style is hairless in the upper part and slightly longer than the stamens.

The drupe is ellipsoidal, about 3.5 centimeters long and 2-2.5 centimeters in diameter, with a velutinous outer pericarp and a prominently lumpy inner pericarp surface.

The stone is flattened with two distinct ridges, containing one chamber and one seed. The flowering period is in March, and the fruiting period is from May to August.

II. Habitat and Distribution

The species is found in China, India, Myanmar, Bangladesh, Thailand, and the Malay Peninsula, thriving in the evergreen broadleaf forests of valleys and ravines at altitudes of 500 to 800 meters.

It favors warm and humid conditions and thrives in acidic yellow soils, provided there is good drainage.

III. Reproduction Methods

Propagation is achieved through seeding or cuttings. Seeds mature in autumn and are stored dry in sand; prior to sowing, they should be soaked in hot water at 70°C until it cools naturally, then submerged in cold water for one week.

Sow the seeds in rows spaced approximately 20 centimeters apart, covering with about 2 centimeters of soil, and mulch to retain moisture.

When transplanting larger seedlings, it’s beneficial to prune some branches and leaves to reduce water evaporation and aid in the tree’s recovery and growth.

IV. Primary Value

The branches form a towering, pagoda-like crown from top to bottom, magnificent in stature. During blooming, the tree resembles layers of white tassels swaying in the breeze, exuding a creamy fragrance that is enchanting.

The buttress roots at the base of mature trees are particularly impressive, making it an important ornamental species in South China.

It is commonly planted in clusters in gardens, at road intersections, and forest edges, and serves as an excellent street and scenic forest tree. It is also suitable for greening factory areas.

V. Conservation Status

Protection Level

Listed in the “IUCN Red List of Threatened Species” (1998 version 3.1) as Vulnerable (VU).

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