Gardens’ Bulletin Singapore 69(1): 67-73. 2017 
doi: 10.3850/S2010098116000046 
67 
Novitates Bruneienses, 8. Macrosolen brunsing 
(Loranthaceae), a new hemiparasitic shrub 
from Brunei Darussalam 
Y.W. Low 1 , A.K. Muhammad Ariffin 2 , A.A. Joffre 2 & D. Duratul Ain 2 
herbarium, Singapore Botanic Gardens, National Parks Board, 
1 Cluny Road, Singapore 259569 
lo w_y ee_wen@nparks. gov. sg 
2 Brunei National Herbarium, Forestry Department, 
Ministry of Industry and Primary Resources, Jalan Menteri Besar, 
Berakas, BB3910 Brunei Darussalam 
ABSTRACT. Macrosolen brunsing Y.W.Low & Ariffin is described and illustrated here as a new 
species of aerial hemiparasite based on two collections from the Ladan Hills Forest Reserve, 
Tutong, Brunei Darussalam. The new species differs from all Macrosolen taxa enumerated in 
Borneo by its distinct linear leaves ((4—)8—14.5 cm long, 0.1—0.2(—0.25) cm wide). 
Keywords. Borneo, endemic, linear-leaved, Malesia, new species 
Introduction 
The presence of aerial hemiparasitic shrubs of the Loranthaceae in tropical rainforests 
is often overlooked, even when they are flowering, as they are generally concealed 
high-up in the canopy of their host. Although many species produce very spectacular 
inflorescences, often their presence is only revealed by their withered flowers littered 
on forest floor, usually around the base of the trunk of their host. On a recent botanical 
excursion to the Nyamokning Dam construction site in the Ladan Hills Forest Reserve, 
a sterile but striking hemiparasitic shrub with linear leaves (Y.W. Low et al. LYW1059 ) 
was collected from a species of Hydnocarpus Gaertn. (Achariaceae) host growing on 
a ridge at about 150 m asl. Later, the same hemiparasite was spotted in flower and fruit 
(Y.W. Low et al. LYW 1081) on a species of Mallotus Lour. (Euphorbiaceae) host, just 
above the campsite on the same trip. These two collections were closely examined in 
BRUN and SING (herbaria acronyms follow Thiers, (continuously updated)). 
The Ladan Hills plant readily keys to Macrosolen Blume in the Flora Malesiana 
account for Loranthaceae (Barlow, 1997). Based on fieldwork carried out for the 
Brunei Checklist Project, Kirkup (1996) enumerated nine taxa, of which two were 
unidentified. These are Macrosolen beccarii Tiegh. ex Becc., M. borneanus Danser, 
M. cochinchinensis (Lour.) Tiegh., M. crassus Danser, M. curvinervis Danser, M. aff. 
formosus (Blume) Miq., M. retusus (Jack) Miq., M. sp. A and M. sp. B. Of the nine taxa 
listed by Kirkup (1996), only six were recognised by Barlow (1997) in his revision of 
the genus for Malesia, as M. borneanus is considered a synonym of M. beccarii , and 
