Comparative morpho-anatomical studies of Hoya incrassata and Hoya soligamiana (Apocynaceae) from Mount Hamiguitan, Philippines

DS Salas, EB Sinamban, DP Buenavista


This study compared the morpho-anatomical characters of two horticulturally important hoyas endemic to the Philippines viz., Hoya incrassata and Hoya soligamiana. Fresh cuttings were used for morphological and anatomical measurements. Free hand sections were taken from leaves, shoots and roots for determination of structural differences. Leaf pigments were cleared to observe the venation and stomatal arrangement. The results showed that hoyas differ in their leaf shape and texture, flower colour, and the inflorescence shape and position. H. soligamiana has glabrous lanceolate leaves, whitish to creamy petals, purplish to pink inner and outer coronal lobes, and whitish to pink fused sepals. H. incrassata has coriaceous lance-ovate leaves, whitish to yellowish fused petals, yellow inner coronal lobes, reddish to orange outer coronal lobes, and fused sepals. The measured anatomical traits in the cross sections of roots and stems of the two Hoya species did not differ with the exception of stomatal types and arrangement in the leaves. The pigment clearing of the leaves showed that H. incrassata has sunken cyclocytic stomata while H. soligamiana has actinocytic stomata. Morpho-anatomical information provides taxonomic value for identifying and classifying the two Hoya species.

Keywords. Endemic hoyas, morphology, Mindanao, plant diversity, taxonomy, wax plants.

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Averyanov LV, Pham VT, Maisak TV, Le TA, Nguyen VC, Nguyen HT, Nguyen PT, Nguyen KS, Nguyen VK, Nguyen TH, Rodda M. 2017. Preliminary checklist of Hoya (Asclepiadaceae) in the flora of Cambodia, Laos and Vietnam. Turczaninowia 20 (3): 103–147, doi:10.14258/turczaninowia.20.3.10

Aurigue FB, Sahagun JR, Suarez WM. 2013. Hoya cutis-porcela (Apocynaceae): a new species from Samar and Biliran Islands, Philippines. Journal of Nature Studies 12 (1): 12-17.

Baas WJ, Warnaar F, Niemann GJ. 1981. Investigations on Hoya species. VI. Latex composition and leaf phenolics and their taxonomic significance. Acta Botanica Neerlandica 30: 257e263.

Borlagdan M, Aurigue FB, Van Altena IA, Ragasa CY. 2016. Triterpenes from Hoya paziae Kloppenb. Pharmacognosy Journal 8 (5): 487-489.

Buenavista D, Mateo MT. 2017. Histochemical Screening and Medicinal Potentials of Garuga floribunda in Mindanao Island, Philippines. Annals of West University of Timisoara, Series of Biology 20 (2):147-152.

Chuakul W. 2005. Medicinal plants in the Khok Pho District, Pattani Province (Thailand). Thai Journal of Phytopharmacology 12: 23-45.

de Faria AP, Vieira ACM, Wendt T. 2012. Leaf anatomy and its contribution to the systematics of Aechmea subgenus Macrochordion (de Vriese) Baker (Bromeliaceae). Anais da Academia Brasileira de Ciências 84 (4): 961-971.

Esau K. 1977. Plant Anatomy. 2nd Edition. John Wiley & Sons, Inc. London. 576p.

Fernando ES, Co LC, Lagunzad DA, Gruezo WJ, Barcelona JF, Madulid DA, Lapis AB, Texon GJ, Manila AC, Zamora DPM. 2008. Threatened Plants of the Philippines: A preliminary assessment. Asia Life Sciences, Supplements 3: 1 – 52.

Forster PI, Liddle DJ, Liddle DIM. 1998. Diversity in the genus Hoya (Asclepiadaceae – Marsdenieae). Aloe 35: 44 – 48.

Gautam TP. 2013. Indigenous uses of some medicinal plants in Panchthar district, Nepal. Nepalese Journal of Biosciences 1: 125-130.

Johanssen D. 1940. Plant Microtechnique. New York: McGraw Hill Book Company. 523p.

Heneidak S, Grayer RJ, Kite GC, Simmonds MSJ. 2006. Flavonoid glycosides from Egyptian species of the tribe Asclepiadeae (Apocynaceae, subfamily Asclepiadoideae). Biochemical Systematics and Ecology 34: 575-584.

Kidyoo M, Thaithong O. 2007. A new species of Hoya (Asclepiadaceae) from southern Thailand. Blumea 52: 327-330.

Kleijn D, Donkelaar R. 2001. Notes on the Taxonomy and Ecology of the genus Hoya (Asclepiadaceae) in Central Sulawesi. Blumea 46: 457 – 483.

Kloppenburg D. 2009. Philippine Hoya Species (monograph). Fresno, California. 704p

Kloppenburg D. 2006. The World of Hoyas, a pictorial guide. Fresno, California. pp. 31 – 34.

Li PT, Gilbert MG, Stevens WD. 1995. Asclepiadaceae. In: Flora of China. Ed. Wu ZY, Raven PH. Sci. Press, Beijing & Missouri Bot. Garden Press, St. Louis, 16: 228–236.

Madulid D. 1994. Plant Diversity in the Philippines. Academia Sinica. Monograph Series14:105 – 109.

Mollik MAH, Hossan MS, Paul AK, Taufiq-Ur-Rahman M, Jahan R, Rahmatullah M. 2010. A comparative analysis of medicinal plants used by folk medicinal healers in three districts of Bangladesh and inquiry as to mode of selection of medicinal plants. Ethnobotany Research and Applications 8: 195-218.

O’brein TP. 1974. Primary Vascular Tissues. In: Dynamic aspects of plant ultrastructure. A. W. Robards, ed. Chapter 12. London, McGraw-Hill Book Company (UK) Limited, 414 – 440 pp.

Pelser PB, Barcelona JF, Nickrent DL. 2011. Philippine Plants: An Analysis of the Flora. In Co's Digital Flora of the Philippines,

Phelp J, Webb EL. 2015. “Invisible” wildlife trades: Southeast Asia’s undocumented illegal trade in wild ornamental plants. Biological Conservation 186: 296-305. doi: 10.1016/j.biocon.2015.03.030

Posa MRC, Diesmos AC, Sodhi NS, Brooks TM. 2008. Hope for threatened tropical biodiversity: lessons from the Philippines. Bioscience 58:231–240. doi: 10.1641/B580309

Rodda M. 2012 Taxonomy of Hoya lyi, Hoya yuennanensis and Hoya mekongensis (Apocynaceae–Asclepiadoideae). Edinburgh Journal of Botany 69 (1): 83-93.

Schweingruber FH, Borner A, Schulze ED. 2011. Atlas of Stem Anatomy of Herbs, Shrubs and Trees. Springer-Verlag Berlin Heidelberg: Germany. 1: 54 – 60 pp.

Sharifnia F, Albouyeh RM. 2002. Anatomical studies in relation to taxonomy of Persian Linum species. Pakistan Journal of Biological Sciences 5 (11): 1240–1245.

Siar S. 2005. Philippine Hoyas. Philippine Council for Agriculture, Forestry and Natural Resources Research and Development. Laguna, Los Baños. 23p

Standley LA. 1990. Anatomical aspects of the taxonomy of sedges (Carex, Cyperaceae). Canadian Journal of Botany 68:1449-1456.

Tran TB, Rodda M, Kim JH, Lee DK, Ha BT. 2011. Hoya sapaensis (Apocynaceae, Asclepiadaceae), a new species from Vietnam. Annales Botanici Fennici 48: 511 – 514. doi: 10.5735/085.048.0612

Tsiang Y, Li PT. 1977. Asclepiadaceae – In: Tsiang Y, Li PT (eds). Flora republicae Popularis Sinicae, Sci. Press, Beijing. 63: 475 – 492.


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