Derrick Posted February 22, 2014 Report Share Posted February 22, 2014 As far as I am aware, Australia has no ant gardens, hence in the island continent this non-obligate myrmecophyte species tends to be an occasional semi-parasite on the ant and plant relationships of myrmecodomic (ant-house) species. It is not parasitic in the sense seen in mistletoe species. However, in southern Asia, it is a frequent symbiont of ant gardens where the relationship is mutualistic. Its seed is attractive to ants which take them into their epiphytic nests where they may germinate. Edited. Dischidia nummularia with tubers of myrmecodomic (ant-house) myrmecodias. Iron Range National Park, Cape York Peninsula, North Queensland, Australia.JPG] Link to comment Share on other sites More sharing options...
jeff Posted February 22, 2014 Report Share Posted February 22, 2014 I am not sure that there is mutualism with this sort of Dischidia ? Link to comment Share on other sites More sharing options...
Derrick Posted February 22, 2014 Author Report Share Posted February 22, 2014 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/5337%C2'> Dr Eve Kaufmann's excellent thesis can be downloaded from this site. It provides plenty of proof that D. nummularia and indeed many other laminate leafed dischidias are optional symbiotic mutualists because of their occurrence in ant gardens. Indeed, some may be obligate. Link to comment Share on other sites More sharing options...
DischidiaGuy Posted February 23, 2014 Report Share Posted February 23, 2014 Hemi parasite? I can't imagine the roots of Dischidia nummularia penetrating the caudex. Is this the case? Link to comment Share on other sites More sharing options...
Derrick Posted February 23, 2014 Author Report Share Posted February 23, 2014 Dischidia nummularia Richard Brown. Published in Prodromus Florae Novae Hollandiae 1810 by R. Brown in the very first flora of Australia ever published. Type Collection: Australia, Queensland, Endeavour River - a Banks & Solander collection made during Captain Cook’s famous voyage of exploration. Synonyms: Collyris minor Vahl in Skrifter af Naturhistorie-Selskabet 1810. Dischidia minor (Vahl) Merrill in Lingnan Science Journal 1934. Dischidia gaudichaudii Joseph Decaisne in Prodromus Systematis Naturalis Regni Vegetabilis 1844. Dischidia orbicularis Decaisne in Candolle, Alphonse Louis Pierre Pyramus de 1844. Nummularia lactea minor Rumphius possibly published in Herbarium Amboinense the first treatise of Moluccas (Spice Island) plants 1741; hence, long after Rumphius’s death in 1702. Description: Epiphytic herb, 10-50 cm (4-20 inches) long, with a much divided, smooth stem. Leaves, flat, smooth, all similarly shaped, broadly oval-orbicular and with a very short point, 1-1.5 times as long as wide, measuring 4-11 by 4-8 mm; their tops appear coated with ‘powder’ and may be dotted, undersides not dotted, but obscurely veined. The plant size in this description is far too conservative; in well-nourished sites, this species can attain far larger sizes. Indeed, some trees in Malaysia become so overburdened with massive growths of D. nummularia that they collapse. Flowers form between the stalks of leaf pairs or at branchlet endings in dense, often umbrella-shaped stalked-groupings. The calyx smooth, but inside a red, 3 mm-long corolla there is a tuft of hairs at the base of each segment. The circle of scale-like appendages between corolla and stamens is divided into two segments. Fruits are 2.5-4 cm long and again parachute-equipped seeds have attached elaiosomes (food bodies) for manipulating ants. Range: Again, an immensely widespread, hence extremely successful species that consequently is very variable occurring as it does from India right across southern Asia to southern China. It is reported from Northeast India, Sri Lanka (Ceylon) Bangladesh, Andaman & Nicobar Islands (as D. minor, http://www.checklist.org.br/getpdf?SL133-08,) Burma, Thailand, Cambodia, Laos, Vietnam, Peninsular Malaysia, Singapore, Philippines, Indonesia, Timor, New Guinea and the Bismarck Archipelago, Northeast Australia and the Solomon Islands archipelago. In China, it is reported from the Provinces of Fujian, Guangdong, Guangxi, Hainan Island, and S. Yunnan. Although not an ant-house plant, this species intimately shares the habitats of myrmeco-epiphytes, frequently sprawling over them. Therefore, one must wonder if D. nummularia might habitually send invasive roots into the composts within neighbouring ant-domatia, initially assisted in such endeavours by its wind-dispersed and elaiosome-enhanced, ant-attractive seeds. Indeed, there are hints in some very early literature. I quote “D. gaudichaudii Decne. (Joseph Decaisne) although lacking apparent myrmecophytic adaptations itself, usually grows with other myrmeco-epiphytes, its roots often entering the chambers of Myrmecodia and Hydnophytum (Holttum 1954, Janzen 1974, cited by Huxley 1978.) D. gaudichaudii is now considered to be a small variety of D. nummularia - a very revealing connection. Indeed, the very observant Drs van Leeuwen (1911) recorded a D. nummularia seedling that had actually germinated inside a damaged D. major domatia leaf and was emerging from it. D. nummularia is obviously a frequent hemiparasite of ant-plant mutualisms but this freeloading relationship is not obligate because D. nummularia is certainly able to survive on its own, at least in habitats that are more equable. A hemiparasitic plant obtains some nourishment from its host but is able to photosynthesize. However, in this example D. nummularia is a parasite of plant and ant mutualisms. Furthermore, Dr Eve Kaufmann in her world leading study of palaeotropic ant-gardens, records this species as a regular ant-garden inhabitant. (Kaufmann 2002.) Hence. in such situations it is performing a mutualistic function with ants. I rest my case. Link to comment Share on other sites More sharing options...
DischidiaGuy Posted February 23, 2014 Report Share Posted February 23, 2014 If the roots enter the chambers, is it not then feeding from the detritus that would reside there from the ants, not necessarily from the plant itself? Does not a plant parasite have to actually feed from the vascular system of the host in order to be a parasite? I would just call this an opportunistic species rather than hemi-parasitic if that's the case. If the roots are in the flesh, then that would make sense to me. People once thought that Dischidia singularis was parasitic as well. Link to comment Share on other sites More sharing options...
Andreas Wistuba Posted February 23, 2014 Report Share Posted February 23, 2014 If the roots enter the chambers, is it not then feeding from the detritus that would reside there from the ants, not necessarily from the plant itself? Does not a plant parasite have to actually feed from the vascular system of the host in order to be a parasite? I would just call this an opportunistic species rather than hemi-parasitic if that's the case. If the roots are in the flesh, then that would make sense to me. People once thought that Dischidia singularis was parasitic as well. But this is parasitism - the plant feeds from the ant plant's food supply that was "produced" by the ants. Link to comment Share on other sites More sharing options...
DischidiaGuy Posted February 23, 2014 Report Share Posted February 23, 2014 I guess I have a problem with the word parasite. Perhaps, thief would be better suited. Link to comment Share on other sites More sharing options...
Aurélien Posted February 24, 2014 Report Share Posted February 24, 2014 I guess I have a problem with the word parasite. Perhaps, thief would be better suited. I agree, "parasitic" for a plant, is a word with a really precise definition. Andreas Fleischmann is also a specialist of the subject! An holoparasitic plant have no chlorophyll at all, like Rafflesia, Orobanche... and eat directly elaborate sap. A semi-parasitic plant eat raw sap ant could have some chlorophyll, just like Viscum, Euphrasia... This Dischidia is only opportunistic for me. As some plants are opportunistic to grow in the humus accumulate in big Platycerium, or like some Utricularia colonize the big bromeliad tanks... Link to comment Share on other sites More sharing options...
Andreas Wistuba Posted February 24, 2014 Report Share Posted February 24, 2014 I agree, "parasitic" for a plant, is a word with a really precise definition. Andreas Fleischmann is also a specialist of the subject! An holoparasitic plant have no chlorophyll at all, like Rafflesia, Orobanche... and eat directly elaborate sap. A semi-parasitic plant eat raw sap ant could have some chlorophyll, just like Viscum, Euphrasia... This Dischidia is only opportunistic for me. As some plants are opportunistic to grow in the humus accumulate in big Platycerium, or like some Utricularia colonize the big bromeliad tanks... I'll check with Andreas about his views... Link to comment Share on other sites More sharing options...
Derrick Posted February 25, 2014 Author Report Share Posted February 25, 2014 Renowned Professor Daniel H. Janzen calls this species (as gaudichaudii) and Pachycentria tuberosa "plant parasites" in the following article that can be read online. http://www.jstor.org/discover/10.2307/2989668?uid=3738776&uid=2129&uid=2&uid=70&uid=4&sid=21103452417401 However, you have answered a question that has been bothering me since I wrote my notes. They obviously need clarification and removal of the word hemi from parasite, but the word parasite is accurate in describing the non-obligate relationship between D. nummularia and myrmecodomic members of its varied epiphytic synusiums. Parasitism is a non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host. http://en.wikipedia.org/wiki/Parasitism Link to comment Share on other sites More sharing options...
Derrick Posted March 22, 2015 Author Report Share Posted March 22, 2015 Clarified. Link to comment Share on other sites More sharing options...
Derrick Posted September 23, 2015 Author Report Share Posted September 23, 2015 Australian Dischidia nummularia probably have larger leaves than most other populations of this immensely widespread species. Link to comment Share on other sites More sharing options...
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