Poikilogyne cordifolia (Cogn.) Mansf., a newly recorded genus and species of Melastomataceae for Australia

2012·1.5 MB·English

by  Ashley R Field

Austrobaileya 8(4): 613-615 (2012)
SHORT COMMUNICATION
Poikilogyne cordifolia (Cogn.) Mansf., a newly recorded
genus and species of Melastomataceae for Australia
Ashley R. Field
Queensland Herbarium, Department of Science, Innovation, Information Technology and the Arts,
Brisbane Botanic Gardens, Mt Coot-tha, Toowong, Queensland 4066, Australia & Australian Tropical
Herbarium, James Cook University Cairns Campus, Smithfield, Queensland 4878, Australia. Email:
[email protected]
Melastomataceae is a diverse family of plants These veins are interconnected by cross veins
in the order Myrtales (A.P.G. 2009). The which give the leaves a laddered appearance
family comprises more than 4500 species typical of many Melastomataceae. The leaf
and 150 genera (Renner 1993) and exhibits margins of many Poikilogyne, particularly
its highest diversity in the Neotropics, with the montane species, are toothed in some
secondary centres of diversity occurring in way and the indument of the leaves, buds and
the Malesian and African regions (Renner stems is variable with many species being
1993; Cellinese 2007). Even though Cape scurfy or villose. The inflorescences are
York Peninsula, Queensland is relatively usually terminal and multi-branched and bear
close to the Malesian region it harbours only 5-merous flowers (also 4-6 merous) with 10
five indigenous Melastomataceae species actinomorphic stamens and a campanulate
from four genera (Bostock & Holland five ribbed hypanthium (also 4-6 ribbed).
2010). Approximately 60% of the Australian The anthers are described by Cellinese
Melastomataceae flora has been introduced by (2007) as having a very small terminal pore,
humans via the horticultural trade, including a prominently thickened connective and an
the significant environmental weeds Clidemia obtuse basal spur. The fruits are dehiscent,
hirta (L.) D.Don, Mikania micrantha Kunth longitudinally splitting capsules borne in
and Miconia calvescens DC. (Bostock & a distinct 10 ribbed cup (also 8-12 ribbed)
Holland 2010). Therefore, upon receiving an formed by the hypanthium. The fruit of
attractive and unidentified Melastomataceae Poikilogyne are dry and capsular and the
collected from Cape York Peninsula it was seeds are small. This is consistent with the
initially expected that it belonged to a weedy wind-dispersal mode for Melastomataceae
horticultural species. Closer examination of rather than bird dispersal found in species
the buds, leaf type, fruit type and anthers with berry type fruits (Styles & Rosselli
indicated that it belonged to the widespread 1993).
New Guinea species Poikilogyne cordifolia
Maxwell (1983) reduced Poikilogyne
Mansf and that it is likely to be indigenous.
ledermannii Mansf. to varietal rank within P.
It is the first record of the genus Poikilogyne
cordifolia but did not provide any characters
Baker f. outside Malesia.
to distinguish the two varieties. Based on
Poikilogyne is a genus of more than 20 Mansfield’s (1926) circumscription of the two
species with a centre of diversity in New taxa, and on material held in BRI that have
Guinea where there are a number of narrow been determined by J.F.Maxwell, I consider
range endemics (Cellinese 2007). Most that the Australian specimen belongs to
Poikilogyne are terrestrial shrubs or vines Poikilogyne cordifolia var. cordifolia.
with ovate to orbicular leaves with major
Poikilogyne cordifolia (Cogn.) Mansf., Bot.
veins radiating from the cordate leaf base.
Jahrb. Syst. 60: 111 (1926); Allomorphia
cordifolia Cogn., FI. Kais. Wilh. Land [K.M.
Accepted for publication 30 October 2012
Schumann & M.U. Hollrung] 87 (1889). Type:
614 Austrobaileya 8(4): 613-615 (2012)
Papua New Guinea, s.loc., in 1886, [U.M.] decayed dry membrane bearing 10 persistent
Hollrung 135 (holo: Bf; iso: BR 5214778, woody longitudinal ribs, corresponding with
scan!). the mid-vein and marginal veins of the sepals,
which grip the ovary. Seeds numerous per
Poikilogyne cordifolia var. cordifolia;
locule, less than 1 mm long, brown. Fig 1.
J.F.Maxwell, Gard. Bull. Singapore 35: 223
(1983). Selected specimens examined: Indonesia. Papua.
Bernhard Camp, Idenburg River, Mar 1939, Brass
Description of Australian specimen: 13069 (BRI). Papua New Guinea. Owen Stanley Range
Branching woody shrub to 1 m tall with between Mts Brown & Clarence, May 1926, Brass
tetrangular stems bearing a distinct keel 1488 (BRI). Australia. Queensland. Cook District:
Munburra, Starcke, Sep 2012, Thompson 691 (BRI,
along the corners of young and mature stems.
CNS).
Immature shoots with a reddish-pink blush,
mature bark pale yellow-brown with a few Distribution and habitat: This species is
presently known in Australia from a single
raised corky lenticels. All parts of stems,
leaves, flowers and fruits glabrous. Leaves record at Munburra, Starcke on eastern Cape
York Peninsula where it was growing on steep
and branchlets opposite with a distinct
interpetiolar scar. Petioles fleshy, 16-110 mm metamorphic rocky slopes on an ecotone
long, reddish pink. Leaves orbicular-cordate, between Eucalyptus and Lophostemon
60-160 mm long by 60-120 mm wide, dominated forest and rainforest. This
species is widespread and abundant in New
with a distinctly cordate base and a weakly
Guinea and it is expected that it will be more
acuminate apex; midvein and 2-4 pairs of
widespread in other similar, poorly accessed,
major lateral veins all radiating from the leaf
base petiole junction and interconnected by habitats on eastern Cape York Peninsula.
secondary cross veins; all venation prominent Notes: The site where Poikilogyne cordifolia
on both surfaces and distinctly raised on was collected is remote, undisturbed and
the abaxial surface. Inflorescences terminal did not contain any introduced plant species
thyrses, 50-150 mm long and 50-150 mm (S.Thompson pers. comm.). This species is
wide, reddish-pink, with flowers opening unknown in cultivation in Australia and it is
sequentially. Inflorescence bracts minute, considered unlikely that it has been introduced
reddish-pink, sometimes absent. Flowers via the horticultural trade. Combined, these
5-merous, occasionally 4 or 6-merous within factors indicate that Poikilogyne cordifolia
the same inflorescence. Pedicels 7-9 mm long is indigenous to Australia and that it has
and 1 mm in diameter. Hypanthium 9-14 mm naturally dispersed to Australia from Papua
long and 4-9 mm in diameter, pink, with 5 New Guinea. Poikilogyne cordifolia is readily
apically ribbed obtuse calyx lobes. Petals distinguished from all other Australian
free (imbricate in bud), rounded-oval with Melastomataceae by its large orbicular-heart
a small keel apically, 6-9 mm long and 4-9 shaped cordate leaves and by its capsular
mm wide, bicolored, pink and white. Anthers loculidically splitting fruit which are clasped
actinomorphic, 4-6 mm long with a terminal by the ribs of the sepals and hypanthium.
pore and a small basal spur. Filaments 5-6
mm long at anthesis. Anthers and filaments Conservation status: Insufficient data are
folded inwards when flowers first open. available to accurately assess the conservation
Ovary half-inferior, truncate, style less than status of Poikilogyne cordifolia in Australia.
5 mm long when flowers open elongating Poikilogyne cordifolia is abundant in New
to 13 mm long and bearing a simple white Guinea and could be considered secure there.
to reddish-pink stigma. Inflorescences and Acknowledgments
fruit becoming dry and woody at maturity
and remaining attached to the plant in I would like to thank Simon Thompson for
branch sinuses. Fruits dry, dehiscent, collecting the voucher material and also
loculidically splitting, capsules with sepals Nicoletta Cellinese and Trevor Whiffin for
and hypanthium reducing to a thin partially confirming the identification.
Field, Poiklogyne cordifolia 615
References Mansfield, R. (1926). Die Melastomataceen von
Papuasian. Botanische Jahrbiicher fur
A.P.G. [=Angiosperm Phylogeny Group.] Ill (2009). An Systematik, Pflanzengeschichte und
update of the Angiosperm Phylogeny Group Pflanzengeographie 60: 105-143.
classification for the orders and families of
flowering plants: APG III. Botanical Journal of Maxwell, J.F. (1983). Taxonomic and nomenclatural
the Linnaean Society 161: 105-121. notes on Oxyspora,Anereincleistus, Poikilogyne
and All'omorphia (Melastomataceae). Gardens’
Bostock P.D. & Holland A.E. (eds.) (2010). Census Bulletin Singapore 35: 209-226.
of the Queensland Flora 2010. Queensland
Herbarium, Department of Environment and Renner, S.S. (1993). Phylogeny and classification of the
Resource Management: Brisbane. Melastomataceae and Memecylaceae. Nordic
Journal of Botany 13: 519-540.
Cellinese, N. (2007). Two new species in the genus
Poikilogyne (Melastomataceae) from Papua Styles, F.G. & Rosselli, L. (1993). Consumption of fruits
New Guinea. Novon 17: 20-23. of the Melastomataceae by birds: how diffuse is
coevolution? Vegetatio 107/108: 57-73.
Fig. 1. Poikilogyne cordifolia. A. flowering and fruiting branch. B. lateral view of flower buds. C. lateral and apical
view of mature dehiscent capsules. All from fresh material of Thompson 691 (BRI). Photographs by Andrea Lim.