ISSN 2816-6531

Heimia Link (Lythraceae): A new introduced genus record in Malesia

Arifin Surya Dwipa  
Irsyam  
Muhammad Rifqi  
Hariri  
Rohman  
Rohman  
Rina Ratnasih  
Irwanto  
Tags: Heimia salicifolia, Indonesia, West Java, Lythraceae, Magnoliophyta, Melasia, Myrtales
Number 9, 
21 February 2023

Introduction

The genus Heimia Link (Lythraceae) has a native distribution in Mexico to Argentina, with three species described (Graham et al., 2009; Rodas & Briones, 2010). Previous research indicates that the genus has never been found in Malesia, including Java (Backer & Bakhuizen van den Brink, 1963; de Wilde & Duyfjes, 2016). However, during an exploration in Jatinangor Sub-district, Sumedang Regency, West Java, Indonesia, we collected a specimen identified as a species belonging to Heimia. This discovery brings the total number of Lythraceae of Malesia to 12 genera. In the Malesia region, Heimia is represented only by one species, H. salicifolia Link. A morphological description, discussion, and photographs are given below.

Results and Discussion

Heimia salicifolia Link, Enum. Hort. Berol. Alt. 2: 3 (1822) Figure 1.

Shrub, up to 2 m tall. Stem with flaky bark, brown, glabrous. Branchlets quadrangular, ridged, glabrous, green. Leaves simple, alternate, sub-sessile; lamina narrowly elliptic, lanceolate to oblong, 10‒35 × 3‒6 mm, base cuneate, margin entire, apex acute, adaxial surface dark green, abaxial surface glaucous. Flowers solitary, axillary, bisexual, sub-sessile; peduncle 1 mm long; bracteoles 2, elliptic to linear, 3‒3.5 × 1 mm, green. Floral tube campanulate, persistent, green; sepals valvate, 6, persistent; epicalyx appendages alternating with sepals, longer than sepals; petals 6, ca. 5 mm wide, rotund, yellow; stamens 12, ca. 4 mm long; filaments filiform, yellowish green; anthers oblong, versatile, yellow; ovary subglobose, green; style filiform, ca. 6 mm long, yellowish, persistent in fruit; stigma capitate, greenish. Fruit capsule, 4‒6-celled, subglobose, ca. 4 mm in diameter, 6-nerved, green. Seeds numerous, obconical, non-winged.

Heimia salicifolia is an introduced species native to Central and South America (Stanley & Ross, 1986; Rodas & Briones, 2010). Distribution of this species outside its native range have been reported in Australia (Stanley & Ross, 1986) and Zimbabwe (Maroyi, 2006). The species has been introduced to Java as an ornamental shrub or bonsai, and it is known as “suweng” or “ki ecep” by Indonesian bonsai enthusiasts. Nonetheless, the history of this species' introduction in Java is unknown. The oldest record for this species, according to the specimen filed in FIPIA, was collected by SM Popta in 1952 from Bandung, West Java.

In our study area, the species is grown in cultivation at 700 m asl. However, its wild population was discovered along a ditch and appeared to have escaped cultivation. The seeds are tiny and easily dispersed by water. Heimia salicifolia has a high potential for invasiveness and was reported as a naturalized species in Australia (Stanley & Ross, 1986).

Material

References

1.

Backer C.A., Bakhuizen van den Brink R.C., 1963. Flora of Java. Vol. I. N.V.P. Noordhoff, The Netherlands, xxxiii + 648 pp.

2.

de Wilde W.J.J.O, Duyfjes, B.E.E., 2016. Lythraceae. Flora Malesiana – Ser. 1, Spermatophyta, 22: 1-64.

3.

Graham, S.A., Gandhi, K., Ramella, L., Perret, P., 2009. The correct name for Heimia myrtifolia Cham. & Schltdl. (Lythraceae): Heimia apetala (Spreng.) SA Graham & Gandhi, comb. nova. Candollea, 64(2): 306.

4.

Maroyi A., 2006. Preliminary checklist of introduced and naturalized plants in Zimbabwe. Kirkia, 18(2): 177-247.

5.

Rodas R.D., Briones J.M., 2010. Flora del Paraguay 40: Lythraceae. Conservatoire et Jardin botaniques, Ville de Geneve, 152 pp.

6.

Stanley T.D., Ross E.M., 1986. Flora of south-eastern Queensland. Vol. II. Queensland Department of Primary Industries, Australia, iii + 623 pp.

Figure

Heimia2-1

Figure. Heimia salicifolia. A. Flowering branchlet, B. Flower, C. Ovary showing persistent floral tube, D. Ovary in transverse section.