Hydnophytum Jack

Hydnophytum Jack View in CoL

[ Nidus formicarum niger Rumph. (1750) 119, t. 55: 1; Hensch. (1833)].

Hydnophytum Jack (1823) 124; Blume (1826) 955; DC. (1830) 450; Endl. (1838) 539; Benth. & Hooker (1873) 132; Miq. (1869) 256 (sphalm. Hydrophytum ); Becc.(1884) 120; K.Schum.(1891) 123; Valeton (1927) 127;Merr. & L.M.Perry (1945) 14; Darwin (1979) 35; P.Royen (1983) 2666; A.C.Sm. (1988) 192. — Type species: H. formicarum Jack.

Lasiostoma Spreng. (1825) 423; Benth. (1843) 224; Baill. (1880) 459.

Myrmecodia auct. non Jack: Gaudich. in Freyc. (1830) 472, t. 95; A.Rich. (1834) 224; Baill. (1880) 411.

Epiphytic, rarely terrestrial, woody subshrub with cavitied tuber between stem and roots. Tuber irregularly subglobose, occasionally flattened, fusiform or scaphoid in shape, rarely multiple. Spines usually absent, occasionally root-like or small and tubercle-like, rarely stiff and stellately branching. Entrance holes scattered on surface, or rarely arranged in discrete patterns; more numerous on substrate-facing side of tuber. Cavity shape and wall character variable within the genus. Tuber tissue fibrous to fleshy, yellowish white, rarely purplish red. Cavity surfaces either partly warted, with lenticel-like outgrowths, partly smooth, or entirely smooth. Stems arising from a single origin on the tuber, sometimes a woody boss, at the apex of the tuber, or rarely at several positions; numerous, occasionally one to few, branched; woody, slender, hanging to erect; often with 2 or 4 ridges, rarely winged; spines absent, rarely root-like around the inflorescences. Leaves rounded to lanceolate, to 20 cm in length, more usually less than 15 cm, often less than 2 cm in montane species; leathery, thick to fleshy, more rarely thin and mesophytic. Petiole 0–9 cm. Stipules interpetiolar, rarely splitting between the petioles; usually inconspicuous, occasionally large, with a prominent keel, caducous to persistent. Inflorescence axillary, rarely terminal, paired, rarely single, usually sessile, or peduncle short and unbranched or up to 12 cm in length. Bracts absent, or sometimes, when peduncle is absent, numerous and conspicuous, papery or leathery, sometimes with numerous reddish hairs on inner surfaces, these persistent. Flowers usually heterostylous. Corolla lobes 4, white, rarely green or red/purple tipped, usually with a ring of hairs at or below the corolla tube mouth which form a connivent mass above the corolla lumen. Anthers generally exserted in short-styled flowers, and then larger, also producing larger pollen grains, rarely pollen grains absent in long-styled flowers. Pollen 3-porate or 3- or 4-colporate, (25–)40–60(–130) µm; pores and colpi rarely bordered, exine finely to coarsely reticulate, brochi 1–1.5 µm across; vesicles rare, small. Stigma 2–4 fid, exserted in long-styled flowers, then with shorter and more papillose elements. Fruit baccate, rarely siccate, ovoid to globose, occasionally flattened, often with prominent calyx and disc remains, yellow, pink or red when ripe. Pyrenes 2 (rarely 3 or 4), obovoid to ovoid, and flattened adaxially, apex rounded to narrowly acute or acuminate, or 3-lobed.

Distribution — 55 species. Andaman Islands, Burma, Thailand, Cambodia, Laos, Vietnam, Malaysia, Brunei, Philippines, Indonesia, Papua New Guinea, Australia, Solomon Islands, Vanuatu, Fiji.

Ecology & Habitat — Sea level to above the timber line (3 300 m). Epiphytic in seasonally dry to ever-wet forests: strand-line trees, mangrove forest, seasonal Eucalyptus savannah, primary and disturbed rainforest, Casuarina savannah, agricultural trees, heath forest and other poor-soil sites, montane forest (dry to very mossy), ridge-top forest or upper montane forest. More rarely some species are terrestrial above the tree-line ( H. archboldianum , H. pauper ), in heath forest or scrub at lower altitudes ( H. caminiferum , H. dentrecastense ), occasionally terrestrial on rocky substrates in open-canopied forest ( S. guppyana , H. grandiflorum ), or rarely grow in the leaf litter having fallen from the trees ( H. terrestris ).

KEY TO THE SPECIES

1. Inflorescence peduncles> 3 times as long as broad, branched (sometimes branched so close to stem, that there appear to be 4 in each axil)............................. 2

1. Inflorescence peduncles <3 times as long as broad, unbranched, 1 or 2 in each axil, or inflorescence sessile or sunken in stem................................ 6

2. Inflorescence solitary in each axil; peduncle slender, to 3 mm thick, usually ± flattened......................... 3

2. Inflorescence paired, or apparently 4 in each axil; peduncle thick,> 3 mm thick, terete........................ 4

3. Lamina 5–20 cm long; peduncle trichotomously branched, with 4 or more fertile branch ends; corolla tube slender, at least 3 times as long as broad......... 53. S. guppyana

3. Lamina 2–4 cm long; peduncle dichotomously branched, with 2 or rarely 3 fertile branches; corolla tube scarcely longer than broad......................... 54. S. kajewskii

4. Stem terete; leaves 3–10 cm wide...... 50. H. radicans

4. Stem square; leaves 0.5–2.5 cm wide.............. 5

5. Stem 3–10 mm thick when dry; angles winged; pyrenes 4.................................. 48. H. albertisii

5. Stem 1–2 mm thick when dry; angles not winged; pyrenes 2.............................. 49. H. linearifolium

6. Inflorescence sessile, obscured or filled by a cushion of bracts and/or bract hairs and calyx remains......... 7

6. Inflorescence sunken, sessile or pedunculate, but not obscured by bracts or bract hairs................ 28

7. Lamina 16 by 6 to 40 by 14 cm; inflorescence cushion wider than thickness of stem.......................... 8

7. Lamina never larger than 15 by 4 cm; inflorescence cushion as wide as, or narrower, than stem............... 10

8. Petiole c. 9 cm long; inflorescence bract hairs coalescing to form a large mass that obscures the stem................................... 45. H. mamberamoense

8. Petiole <3 cm long; inflorescence cushions discrete.. 9

9. Lamina base tapering; petiole 0.5–1 cm; bracts mostly hairs, forming a dense cushion; roots arising from nodes.............................. 12. H. trichomanes

9. Lamina base rounded or cordate; petiole <0.5 cm; bracts triangular, papery to leathery; roots not arising at nodes............................... 39. H. bracteatum

10. Corolla lobes and tuber tissue purplish red when fresh 11

10. Corolla lobes white or greenish white, tuber tissue not purplish red when fresh........................ 13

11. Lamina 1.2 by 0.6 to 2 by 1.5 cm; pyrenes 2........................................ 38. H. minirubrum

11. Lamina larger; pyrenes 2–4, usually 3............ 12

12. Lamina elliptic-lanceolate; corolla to 11 mm; fruit 8 mm. — Western New Guinea.......... 36. H. archboldianum

12. Lamina elliptic-obovate; corolla to 15 mm; fruit 5 mm. — Papua New Guinea............. 37. H. magnirubrum

13. Tuber multiple, comprised of more than one globular cavitied swelling articulated by stem or roots....................................... 23. H. multituberosum

13. Tuber solitary, sometimes deeply lobed, but never articulated by stems or roots........................ 14

14. Leaves sessile, base blunt to cordate 17. H. caminiferum

14. Leaves sessile to petiolate, base tapering, always relatively narrow..................................... 15

15. Lamina to 1.3 by 0.6 cm............ 16. H. buxifolium

15. Lamina larger............................... 16

16. Tuber entrance holes numerous, thin-walled cylinders to 1.4 cm high and at least 1 cm across..... 19. H. davisii

16. Tuber entrance holes not so.................... 17

17. Stem prominently winged, with wings c. as broad as stem.............................. 47. H. tetrapterum

17. Stem not prominently winged................... 18

18. Petiole c. 2 cm............................... 19

18. Petiole less than 2 cm......................... 20

19. Leaves succulent; bracts papery, lacking hairs, white. — Vanuatu...................... 55. S. vanuatuensis

19. Leaves not succulent, but sometimes leathery; bracts papery to leathery, brown, grey or sometimes with reddish hairs. — New Guinea.............. 11. H. petiolatum

20. Base of lamina abruptly narrowed................ 21

20. Base of lamina attenuate....................... 24

21. Plant either a low-level epiphyte, or terrestrial; stems 4- angled; lamina 3.5 by 1 to 11 by 4 cm; apex tapering or acuminate........................... 35. H. terrestris

21. Plant epiphytic; stems angled or not; lamina relatively broader, apex blunt to acute.................... 22

22. Bract hairs not a prominent part of the inflorescence, papery bracts being ± as common............ 31. H. hailans

22. Bract hairs forming a prominent proportion of the inflorescence cushion............................... 23

23. Found in New Guinea.............. 11. H. petiolatum

23. Found in Australia............... 8. H. ferrugnineum

24. Lamina 7.5–15 cm long, lanceolate, midrib caniculate; pyrenes fusiform 4 by 1.5 mm. — Moluccas......................................... 3. H. morotaiense

24. Lamina less than 7 cm long, midrib raised to flat above; pyrenes obovate............................. 25

25. Bracts triangular, papery, to 0.8 cm, without hairs... 26

25. Bracts mostly comprising a mass of hairs.......... 27

26. Tuber with short tubercles; leaves to 4 by 1.7 cm; pyrene with blunt apiculus.................... 34. H. reevii

26. Tuber surface smooth; most leaves greater than 4 by 2.1 cm; pyrene apex rounded.......... 32. H. mayuense

27. Midrib prominent above and below; pyrenes obovate, apex rounded.......................... 7. H. ellipticum

27. Midrib prominent below, rarely above, and then pyrene apex truncate, with 3 lobes.......... 11. H. petiolatum

28. Nodes markedly wider than internodes; inflorescence socket-like, sunken into stem................... 29

28. Nodes not, or scarcely, swollen; inflorescence sessile or pedunculate................................. 36

29. Tuber of several separate swellings on stem and roots; corolla 3.5 mm. — Waigeo Island 23. H. multituberosum

29. Tuber solitary, sometimes deeply lobed, but never articulated by stems or roots; corolla usually> 3.5 mm.... 30

30. Tuber with scattered spines; lamina 0.5 by 0.4 cm; corolla 9.5 mm...................... 18. H. confertifolium

30. Tuber without spines; lamina greater than 0.5 by 0.4 cm; corolla various............................... 31

31. Lamina widest below the middle................. 32

31. Lamina widest above the middle................. 33

32. Lamina > 4.8 by 1.9 cm, apex acute. — New Guinea.................................... 7. H. ellipticum

32. Lamina to 3.6 by 3.2 cm, apex obtuse or blunt. — Moluccas................................ 4. H. ovatum

33. Lamina spathulate. — Moluccas..... 5. H. spathulatum

33. Lamina obovate. — Western New Guinea......... 34

34. Stem not winged; petiole 0–0.3 cm.... 6. H. tortuosum

34. Stem winged; petiole 0.3–1 cm.................. 35

35. Leaves 3–6 cm long; stipules to 0.1 cm, blunt....................................... 21. H. kebarense

35. Leaves 5–11 cm long; stipules to 0.6 cm, acute-triangular........................... 47. H. tetrapterum

36. Leaves narrowly ovate, apex acuminate-caudate, <6 cm long, thin in texture; petiole 0–0.4 cm; corolla to 2 mm.................................. 42. H. hellwigii

36. Not the above combination..................... 37

37. Leaves fleshy yellowish green, petiole-midrib base forming a pale, triangular pattern on the lamina............ 38

37. Not the above combination..................... 39

38. Inflorescence a pair of peduncles; leaves to 13 by 7.5 cm.............................14. H. moseleyanum

38. Inflorescence a cluster of (2–)4–6 peduncles; leaves to 24 by 16 cm................... 13. H. grandifolium

39. Inflorescence sometimes or always solitary and ± displaced in each axil................................. 40

39. Inflorescence always paired.................... 43

40. Pyrenes apex apiculate......... 43. H. heterophyllum

40. Pyrenes apex not apiculate..................... 41

41. Lamina cordate; corolla to 3.5 mm. — New Guinea................................... 40. H. cordifolium

41. Lamina elliptic to ovate; corolla 10–46 mm. — Fiji... 42

42. Corolla 15–46 mm, with a ring of hairs in throat; fruit globose, fleshy.................... 51. H. grandiflorum

42. Corolla 10–18 mm, glabrous within; fruit flattened, siccate........................... 52. H. longiflorum

43. Leaves c. 3 times as long as broad or greater...... 44

43. Leaves less than 3 times as long as broad......... 48

44. Internodes <0.4 cm thick...................... 45

44. Internodes> 0.6 cm thick...................... 46

45. Leaves all more or less similar..... 25. H. ramispinum

45. Leaves dimorphic: smaller and less ovate on side branches............................... 26. H. valetonii

46. Leaves 8–15 cm long, less than 2 cm wide; petiole 0.2–1.3 cm. — Borneo......................... 2. H. puffii

46. Leaves often longer, more than 2 cm wide; petiole various. — New Guinea.............................. 47

47. Petiole 1–2 cm; inflorescence bracts <1.5 mm; pyrene apex apiculate................... 9. H. lauterbachii

47. Petiole to 1 cm; inflorescence bracts c. 2 mm long; pyrene apex 3-lobed................... 10. H. magnifolium

48. Leaves less than 2 times as long as broad......... 49

48. Leaves greater than 2 times as long as broad...... 58

49. Leaves less than 3 cm long..................... 50

49. Leaves more than 3 cm long.................... 56

50. Leaf base blunt to cordate...................... 51

50. Leaf base attenuate or tapering................. 52

51. Tuber with several upward-pointing entrance holes extended like chimneys; terrestrial........ 17. H. caminiferum

51. Tuber not as above; epiphytic..... 22. H. microphyllum

52. Leaves less than 1 cm long..................... 53

52. Leaves more than 1 cm long.................... 54

53. Corolla 3 mm....................... 24. H. pauper

53. Corolla 10 mm................... 27. H. vitis­idaea

54. Leaves less than 1.6 by 0.9 cm; calyx ciliate, entire; corolla glabrous internally................. 15. H. alboviride

54. Leaves more than 1.4 by 0.7 cm; calyx dentate; corolla with a ring of hairs............................ 55

55. Tuber flattened, blackish above; leaves subsessile, obovate; calyx markedly 4-dentate, numerous and persistent in axils....................... 28. H. acuminicalyx

55. Tuber globose, grey to brown; leaves elliptic to ovate; calyx scarcely dentate, not persistent in axils............................................ 33. H. myrtifolium

56. Pyrenes apiculate at apex....... 43. H. heterophyllum

56. Pyrenes acute to rounded at apex, but never apiculate 57

57. Leaves usually> 5 cm; calyx entire. — Not in New Guinea............................. 1. H. formicarum

57. Leaves usually <4 cm; calyx dentate. — New Guinea.................................... 31. H. hailans

58. Leaves less than 2 cm long..................... 59

58. Leaves more than 2 cm long.................... 62

59. Tuber fusiform, widest at apex; corolla glabrous inside................................ 30. H. fusiforme

59. Tuber globose; corolla with a ring of hairs or not.... 60

60. Corolla glabrous inside............. 20. H. decipiens

60. Corolla with a ring of hairs..................... 61

61. Main stem bearing paired, slender side branches; leaves clustered, dimorphic, those of the side branches smaller and less ovate..................... 26. H. valetonii

61. Stem not bearing paired branches; leaves not clustered nor dimorphic.................... 16. H. buxifolium

62. Petiole 0.5–3 cm............................. 63

62. Petiole 0–0.5 cm............................. 64

63. Leaves elliptic to obovate, apex and base rounded, midrib flat above....................... 1. H. formicarum

63. Leaves lanceolate to ovate, apex and base acute, midrib prominent above and below......... 44. H. lucidulum

64. Base of leaf blunt to cordate........ 46. H. orichalcum

64. Base of leaf cuneate.......................... 65

65. Stipules to 0.4 cm, leaves drying grey-purplish brown. — Central highlands of Papua New Guinea........................................... 29. H. dauloense

65. Stipules to 0.25 cm, leaves drying glaucous-green. — Milne Bay and Northern Province..... 41. H. dentrecastense

NOTES ON THE DESCRIPTIONS

Tuber , stem, leaf, petiole, stipule and inflorescence measurements are all given in centimetres, whilst, flower, fruit and pyrene dimensions are in millimetres. Leaf sizes are given for particular leaves (smallest and largest) and not as ranges. Pollen was mounted in Kaiser’s glycerol jelly and measured with an eyepiece graticule at a magnification of × 100; size is given in micrometres (µm) and where possible is the average of 10 grains.

The number of flowers dissected for each species is given in square brackets after Flowers. Where heterostyly has not been confirmed (because only a single flower type has been seen for the species), but is probable, it is given as ʻ?heterostylousʼ (11 taxa), or the opposite case as ʻ?not heterostylousʼ (4 taxa: wherein the anthers and stigma are at the same level and are probably homostylous). Overall corolla length is obtained by adding the tube and lobe lengths.

Latitude and longitude is given where known, and where the locality is poorly localised, the minutes are omitted, the implication being that the specimen comes from within the degree square. Collections are enumerated, as far as is possible, in a NW to SE order within each province or region. All specimens have been seen, unless otherwise stated. An identification list is appended.

Typification

Species placed as ‘Uncertain and Little Known Species’ are usually those for which the type is lost, and for which no equivalent material exists, or for which only a single fragmentary specimen is known (we have made an exception for H. contortum var. ledermannii ). We have not conducted a search at Berlin or Manila, and have assumed that many of Valeton and Warburg’s type specimens are lost. We have, therefore, not always selected lectotypes for material that we are synonymising. In the case of H. formicarum and H. hellwigii we have selected epitypes (Art. 9.7 of the Tokyo ICBN) to serve as discriminating elements.