Studies on Homalomeneae (Araceae) of Borneo XIII - New Species of Homalomena

Fig. 2. Homalomena gastrofructa S.Y.Wong, Y.C.Hoe & P.C.Boyce. A. Plants in habitat, Type locality. B. Leaf blade (adaxial view). C. Inflorescence (RH) at late pistillate anthesis. D. Inflorescence, spathe artificially opened, to reveal spadix at onset of pistillate anthesis. Note the relation of the spathe constriction to the junction of the pistillate and staminate flower zones. E. Semi-mature infructescences, in habitat. Note the strongly asymmetrical expansion of the persistent lower spathe. A & B from un-vouchered images; CE from P.C.Boyce & W.S.Yeng AR-2575. Images A & B © Y.C.Hoe; C-E © P.C.Boyce.

Fig. 3. Homalomena ibanorum S.Y.Wong & P.C.Boyce. A. Flowering plant in habitat, Kapit, C.Sarawak. Note the glossy leaf blades. B. Detail of leaf blade (abaxial view) to show the conspicuous red margin. C. Detail of petiolar sheaths showing the conspicuous red staining. DF. Inflorescence at pistillate anthesis in ventral, lateral, and dorsal views. G. Spadix (spathe artificially removed) at pistillate anthesis. H. Detail of the upper pistillate and lower staminate flower zones, showing the short interstice with sterile stamens (staminodes) separating the fertile zones. A. from un-vouchered images; B-H from P.C.Boyce & Wong Sin Yeng AR-3732. Images © P.C.Boyce.

Fig. 1. Homalomena baangongensis L.S.Tung & Y.C.Hoe. A. Flowering plant in habitat, Type locality. B. Leaf blade (adaxial view) to show bright green, rubbery texture. C. Inflorescence at late pistillate anthesis. Note the conspicuous amber resin droplets on the staminate portion of the spadix. D. Inflorescence at early pistillate anthesis. Three types of insect pollinator are present: The smallest and most numerous are nitidulid beetles, and the solitary deep blue beetle (left top margin of the spathe limb) is a chrysomelid; both are pollen robbers. The large brown beetle on the spadix tip is Parastasia, a ruteline scarab, and the confirmed pollinator. E. Spadix (spathe artificially removed) at early pistillate anthesis. A-H from un-vouchered images. Images © Y.C.Hoe.

Fig. 4. A: Homalomena borneensis Ridl. B: Homalomena clandestina P.C.Boyce, S.Y.Wong & Fasih. C. Homalomena ibanorum S.Y.Wong & P.C.Boyce. D. Homalomena ovata Engl. E. Homalomena tirtae Asih, A.Kurniawan & P.C.Boyce. A.-E. Spadix (spathe artificially removed) at pistillate anthesis (A-D), and staminate anthesis (E), and to provide comparison of the five described species of the Homalomena Borneensis Complex. A. from P.C.Boyce et al. AR-2559; B. from P.C.Boyce et al. AR-2385; C. from P.C.Boyce & Wong Sin Yeng AR-3732; D. from P.C.Boyce et al. AR-2361; E. from I Gede Tirta GT.2105. Images A-D © P.C.Boyce; E. © Ni Putu Sri Asih, used with permission.

Fig. 5. Homalomena passa S.Y.Wong & P.C.Boyce. A. Type plant in habitat. B. Leaf blade, abaxial view. C. Detail of leaf blade, abaxial view, showing the vein-like pellucid glands. D. Inflorescence at pistillate anthesis. E. Spadix (spathe artificially removed) at pistillate anthesis. Note the pendent interpistillar staminodes. A-E from P.C.Boyce et al. AR-1987. Images © P.C.Boyce.

Fig. 7. Homalomena velutipedunculata S.Y.Wong, Y.C.Hoe & P.C.Boyce. A. Plant in habitat, Type locality. B. Detail of petiole bases. C. Developing infructescences. Note the velvety texture. All from P.C.Boyce, Wong Sin Yeng & S.Maclean. Images © P.C.Boyce & Y.C.Hoe.

Fig. 8. Homalomena velutipedunculata S.Y.Wong, Y.C.Hoe & P.C.Boyce. A. Inflorescence at onset of pistillate anthesis, lower spathe artificially opened to reveal spadix. B. Detail of pistillate portion and interstice of spadix (spathe artificially removed) at onset of pistillate anthesis. C. Inflorescence at pistillate anthesis with mating pair of Parastasia beetles (Coleoptera: Rutelinae) on the spadix. D. Inflorescence at staminate anthesis. Note the pollen strands covering the staminate portion of the spadix. The beetle just visible behind the spadix is a chrysomelid, Chaloenus, scavenging pollen. E. Inflorescence at staminate anthesis, lower spathe artificially removed. Note that the interpistillar staminodes have been eaten and that that the pistillate zone is covered with beetle excrement. All from P.C.Boyce, Wong Sin Yeng & S.Maclean. Images © P.C.Boyce & Y.C.Hoe.

Fig. 6. Homalomena galbana Baharuddin S. & P.C.Boyce. A. Leaf blade, adaxial view. Note the distinct quilting of the leaf blade between the primary lateral veins. B. Detail of synflorescence. The inflorescence in the foreground is in the early stage of fruiting, that to the left is at post anthesis, and beginning to become declinate. The open inflorescence is at pistillate anthesis, the one directly behind will be open in three or four days. Just visible is a newly emerging inflorescence, with the rostrum already conspicuously bicoloured. C. Spathe. Note that it is deeply fornicate, and that the margins are recurved. D. Inflorescence at pistillate anthesis with spathe artificially removed. Note that the interpistillar staminodes exceed the associate pistil. Note, too, that the staminodes are directed downwards, and that the lowermost ones are appressed to the stipe. E. Detail of staminate zone. The clusters of 4 stamens per flower are easily seen. All images © Baharuddin Sulaiman.