Anther Wings of the Genus HOYA

The anther wings of a hoya are made up the two sides of a channel that extends inward from an area between two adjacent coronal lobes. This channel ends inward just below the stigmatic surface that is situated at the outer corners of the hoya stylar table. It has been assumed this channel is an adaptive structure that aids in the pollination of a hoya flower. The anther wing sides are made of a rigid material, with a rounded edged upper surface, linear in extent, of various thicknesses. Looking at one surface of this structure (by removing an individual coronal lobe and viewing it in side view) it will be observer that the upper edge is thickened (the rounded edge referred to above) and scythe shaped to various degrees, (as in a scythe) the lower portions are thinner, ending below and inwardly as more of a sharp edge. The channel formed by the tow sides form the anther wing, is not always a continuously smooth surface from the outer end inward to its apex, the channel on occasion has a ridge part way up which would hinder the smooth entry of a pollinia if this were an avenue of pollination.

Below: a top view of a hoya flower to show the anther wings.

Outer apex Inner end just below the retinaculum, where the stigma is located.

Below: the view of the anther wing outer end from the bottom of the corona.

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Outer apex of an anther wing, here with a square end.

The slot also is visible below extending in ward toward the coronal column.

In an attempt to classify the anther wings of the Genus hoya I have divided them into several categories, mostly based on the outer lobe extensions and shape. In some species the outer anther wing apex does not extend beyond the sinus area between two coronal lobes.

1. not extended

Those anther wing apices that extend beyond the sinuses have different apices and also vary in the thickens of the sides.

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2. Apex extended in a acute apex, sides usually thin.

3. Apex extended with sides thick, ends rounded

4. Apex extended with square apices

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5. Apex extended, end with triple (3) apices.

6. Anther wing extends down corona sinus and around toward the central column

In addition to the above delineations there are differences in how deeply scythe shaped the anther wings are, as seen in a side view of an individual corona lobes shown below. I have not added these to the present presentation as there is an almost continuous variation present from shallow to very deeply “C” shaped.

Here fairly deep to rather shallow.

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Species in each category: 1. Not extended

1. Hoya acicularis Green 2002 2. Hoya bilobata Schlechter 1906 3. Hoya burtoniae Kloppenburg 1990 4. Hoya campanulata Blume 1826 5. Hoya carnosa R. Brown 1817 6. Hoya celata Kloppenburg, Siar, Mendoza, Cajano & Carandang 2012 7. Hoya chiekoae Kloppenburg, Ferreras & Mendoza 2012 8. Hoya cystiantha Schlechter 1913 9. Hoya densifolia Turczaninow 1848 10. Hoya diptera Seemann 1861 11. Hoya eitapensis Schlechter 1913 12. Hoya elliptica Hooker f. 1883 13. Hoya excavata Teijsmann & Binnendijk 1863 14. Hoya fetuana Kloppenburg 2003 15. Hoya fungii Merrill 1934 16. Hoya imbricata Decaisne 1844 17. Hoya kanyakumariana Henry & Swaminathan 1978 18. Hoya kastbergii Kloppenburg 2003 19. Hoya lacunosa Blume 1826 20. Hoya linearis Wallich 1825 20. Hoya littoralis Schlechter 1905 21. Hoya megalaster Warburg 1907 22. Hoya meliflua (Blanco) Merrill (1837) 1908 23. Hoya myrmecopa Kleijn & Donkelaar 1999 24. Hoya nummularioides Costantin 1912 25. Hoya obovata Decaisne 1844 26. Hoya odetteae Kloppenburg 1998 27. Hoya onychoides Forster & Liddle 1995 28. Hoya panchoi Kloppenburg 1988 29. Hoya pauciflora Wight 1848 30. Hoya pentaphlebia Merrill 1918 31. Hoya picta Miquel 1856 32. Hoya poolei White & Francis 1928 33. Hoya pseudolittoralis Norman 1937 34. Hoya quinquinervia Warburg 1904 35. Hoya rosarioae Kloppenburg & Siar 2010 36. Hoya salweenica Tsiang & P. T. Li 1974 37. Hoya skinneriana Kloppenburg & Wayman 2012 38. Hoya smithii Kloppenburg 2010 39. Hoya sp. Tioman Is.

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40. Hoya vitellinioides Bakhuizen 1950 41. Hoya vitiensis Turrill 1917

2. Apex extended in a acute apex, sides usually thin. 1. Hoya acuta Haworth 1821 2. Hoya anncajanoae Kloppenburg & Siar 2008 3. Hoya arnottiana Wight 1834 4. Hoya betchei (Schlechter) Whistler 1978 5. Hoya bicknellii 1999 6. Hoya camphorifolia Warburg 1904 7. Hoya chlorantha Reichinger 1908 8. Hoya chlorantha var. tutuilensis Christopher 1932 9. Hoya chunii Li 1984 10. Hoya cinnamomifolia Hooker 1848 11. Hoya citrina Ridley 1922 12. Hoya cominsii Hemsley 1890 13. Hoya coriacea Blume 1825 14. Hoya cumingiana Decaisne 1844 15. Hoya dischorensis Schlechter 1913 16. Hoya endauensis Kiew 1989 17. Hoya engleriana Hosseus 1907 18. Hoya forbesii King & Gamble 1903 19. Hoya gildingii Kloppenburg 2001 20. Hoya greenii Kloppenburg 1995 21. Hoya ischnopus Schlechter 1913 22. Hoya kenejiana Schlechter 1913 23. Hoya kerrii Craib 1911 24. Hoya kloppenburgii Green 2001 25. Hoya latifolia G. Don 1838 26. Hoya limonica Moore 1921 27. Hoya longifolia Wight ex Wallich 1834 28. Hoya marginata Schlechter 1905 29. Hoya meliflua subsp. fraterna Green 1995 30. Hoya meridithii Green 1989 31. Hoya merrillii Schlechter 1904 32. Hoya nyhuusiae Kloppenburg 2003 33. Hoya querinoensis Kloppenburg & Siar 2007 34. Hoya rigida Kerr 1939 35. Hoya serpens Hooker f. 1883 36. Hoya shephardii Short ex Hooker 1861 37. Hoya siariae Kloppenburg 2000 38. Hoya stoneana Kloppenburg 2006 39. Hoya tomatoensis Green & Kloppenburg 2011

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40. Hoya unruhiana Kloppenburg, Siar, Mendoza, Cajano & Carandang 2012 41. Hoya vitellina Blume 1849 42. Hoya whistlerii Kloppenburg 2002

3. Extended with sides thick ends rounded 1. Hoya albida Kloppenburg, Siar & Cajano 2012 2. Hoya aldrichii Hemsley 1890 3. Hoya andalensis Kloppenburg 2006 4. Hoya apiculata Scheffler 1876 5. Hoya attenuata Christopher 1935 6. Hoya australis subsp nathaliae 2012 7. Hoya australis subsp. australis R. brown 1830 8. Hoya australis var. Tafeta 9. Hoya bicolensis Kloppenburg 2011 10. Hoya bicolor Kloppenburg 2003 11. Hoya blashernaezii Kloppenburg 1999 12. Hoya brittonii Kloppenburg 1992 13. Hoya cagayanensis (Schlechter) Burton 1987 14. Hoya cardiophylla Merrill 1920 15. Hoya caudata Hooker f. 1883 16. Hoya crassicaulis (Elmer) Kloppenburg 1995 17. Hoya darwinii Loher 1910 18. Hoya deykeae Green 2000 19. Hoya diversifolia Blume 1826 20. Hoya diversifolia subsp. elnidicus Kloppenburg 1991 21. Hoya faoensis Kloppenburg 2008 22. Hoya fuscomarginata R. Brown 1910 23. Hoya gigantangensis Kloppenburg 1992 24. Hoya golamcoiana Kloppenburg 1991 25. Hoya imperialis Lindley 1846 26. Hoya inconspicua Hemsley 1894 27. Hoya juannguoana Kloppenburg 2002 28. Hoya leytensis (Elmer) Burton ex Kloppenburg 1991 29. Hoya macgillivrayi Bailey 1914 30. Hoya matavanuensis Kloppenburg 2009 31. Hoya monetteae Green 2004 32. Hoya nagtabonensis Kloppenburg & Wiberg 2002 33. Hoya naumanii Schlechter 1908 34. Hoya nicholsoniae Muller 1866 35. Hoya pallida Lindley 1821 36. Hoya pimenteliana Kloppenburg 1999 37. Hoya polystachya Blume 1848 38. Hoya pottsii Traill 1830

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39. Hoya pubicalyx Merrill 1908 40. Hoya quisumbingii Kloppenburg 2002 41. Hoya recurvula Kloppenburg 2000 42. Hoya retusa Dalzell 1852 43. Hoya revoluta Wight 1883 44. Hoya samoensis Seemann 1866 45. Hoya scortechinii King & Gamble 1903 46. Hoya sipitangensis Kloppenburg & Wiberg 2002 47. Hoya tsangii Burton ex Kloppenburg 1989 48. Hoya wibergiae Kloppenburg 2001

4. Extended with square apices 1. Hoya albiflora Zipp. ex Blume 1848 2. Hoya atimonianensis Kloppenburg & Siar 2006 3. Hoya benguetensis Schlechter 1906 4. Hoya benvergarai Kloppenburg & Siar 2008 5. Hoya bordenii Schlechter 1906 6. Hoya fitchii Kloppenburg & Siar 2010 7. Hoya hainanensis Merrill 1923 8. Hoya lambii Green 2000 9. Hoya lazeroi Kloppenburg & Siar 2008 10. Hoya leucorhoda Schlechter 1913 11. Hoya loyceandrewsiana Green 1995 12. Hoya neoebudica Schlechter 1906 13. Hoya obtusifolia Wight 1834 14. Hoya uncinata Teijsmann & Binnendijk 1862

5. Extended end with triple (3) apices 1. Hoya bella Hooker 1848 2. Hoya buotii Kloppenburg 2002 3. Hoya edanoi Burton ex Kloppenburg 1991 4. Hoya fischeriana Warburg 1904 5. Hoya graveolens Kerr 1939 6. Hoya halconensis Kloppenburg 1990 7. Hoya lanceolata Wallich ex Don 1825 8. Hoya odorata Schlechter 1906 9. Hoya ramosii Kloppenburg & Siar 2007 10. Hoya sp. NS05-225 11. Hoya sp. UC 47136

6. Anther wing extends down corona sinus and around toward the central column

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1. Hoya apoensis Kloppenburg & Siar 2011 2. Hoya brevialata Kleijn & Donkelaar 1999 3. Hoya curtisii King & Gamble 1903 4. Hoya fraterna Blume 1849 5. Hoya heuschkeliana Kloppenburg 1987 6. Hoya heuschkeliana subsp. cajanoae Kloppenburg & Siar 2007 7. Hoya lasiantha Korthals ex Blume 1849 8. Hoya linavergarae Kloppenburg & Siar 2006 9. Hoya loheri Kloppenburg 1991 10. Hoya lucyae Kloppenburg & Siar 2006 11. Hoya memoria Kloppenburg 2004 12. Hoya micrantha Hooker f. 1883 13. Hoya mindorensis Schlechter 1905 14. Hoya mindorensis subsp. superba Kloppenburg 2005 15. Hoya multiflora Blume 1823 16. Hoya nabawanensis Kloppenburg & Wiberg 2002 17. Hoya obscura (Elmer ex Merrill) Burton 1986 18. Hoya pallilimba Kleijn & Donkelaar 1999 19. Hoya paziae Kloppenburg 1990 20. Hoya rizaliana Kloppenburg 1991 21. Hoya rosarioae Kloppenburg & Siar 2012 22. Hoya sigillatis Green 2004 23. Hoya wayetii Kloppenburg 1993 24. Hoya waymaniae Kloppenburg 1995 25. Hoya weebella Kloppenburg 2005

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