Hanguana podzolicola, a new record for Singapore 
163 
Provisional IUCN conservation assessment. The known Extent of Occurrence of 
Hanguana podzolicola is c. 500 km 2 and the species is currently only known from 
three localities, with an estimated Area of Occupancy of c. 10 km 2 . Two of the known 
localities are in protected areas, but the third is highly susceptible to forest loss. The 
species should therefore be considered to be Endangered globally, EN Blab(iii) 
(IUCN, 2012). In Singapore there are c. 50 stems, all solitary, and the majority of them 
are found within a small area (c. 1/2 ha) of particularly wet, low-lying forest, with 
only very few or single stems elsewhere in NSFS. Given the small number of stems, 
small total area of occupancy and the highly clustered distribution, the species should 
be considered Critically Endangered (CR C2) nationally using the slightly amended 
national categories of Davison et al. (2008). 
Additional specimens examined. SINGAPORE: Seletar: 29 Mar 1889, Ridley, H.N. 170 
(SING, female flowers). Central Catchment Nature Reserve: Mandai Road, 28 Jul 1929, 
Corner, E.J.H. s.n. (SING, fully ripe infructescence); forests around Upper Seletar Reservoir, 
19 Aug 2014, Leong-Skornickovd, J. & Thame, A. JLS-3036 (SING, sterile); Mandai Road, 29 
Apr 2015, Leong-Skornickovd, J. & Niissalo, M. HAN-75 (SING, leaf and old infructescence). 
Notes: The fruit colour develops in an unusual way in this species, and the fruits 
illustrated in Siti Nurfazilah et al. (2010) are not yet fully ripe. In the fruits we have 
observed, the fruits have nearly reached their mature size by late April. At this point 
the fruits have a bright pink coloration, but they remain unripe and the seeds remain 
soft. The fruits ripen very slowly and become more translucent over time. As the seeds 
ripen dark brown, the fruits appear dirty greenish-dull pink or even green-brown when 
the seeds are fully developed. This ripening stage lasts for about five months after the 
fruits have their final size (Fig. 1), bringing the total flowering and fruiting process to 
last 7-8 months. 
Singapore plants overall agree closely with measurements from Malaysia (Siti 
Nurfazilah et al., 2010), but the petioles we measured are proportionally longer (1/3 of 
leaf length in Malaysia, up to 1/2 of leaf length in Singapore), and the outer whorls of 
petals are also slightly larger in Singapore than in the Malaysian plants (1 x 1.8 mm in 
Malaysia, 2.5-3 x 2.8-3 mm in Singapore). However, when comparing photographs 
of the fruits of both Malaysian and Singapore collections, the proportional dimensions 
of outer and inner tepals compared to diameter of the fruits appears to be identical. 
Leong-Skomickova & Boyce (2015) discussed the taxonomic importance of 
oblique stigmas in Hanguana and, as they mention, oblique stigmas can occur in 
many Hanguana species when only a single seed develops inside the fruit. However, 
in Hanguana podzolicola (and apparently H. pantiensis) the stigma is very strongly 
oblique, even closer to the base of the fruit than the apex, and such a strongly oblique 
stigma is an unmistakable character of taxonomic significance. It is also well preserved 
in dry material. The species is also characterised by the thick, flocculose indumentum, 
but this character is often lost on old herbarium specimens and also on the older leaves 
of live plants and therefore unreliable for herbarium-based taxonomy. 
