Hyacinth orchid (Dipodium punctatum)

[Pala]

I've seen this flower in a variety of places when bushwalking and have recently found out it's name: Hyacinth orchid (binomial: Dipodium punctatum). Just from the dictionary (Australian Concise OED) I got the following (paraphrased):

Lives in symbiosis with fungus at the root of certain eucalypts, has a tall stalk and deep pink flowers with darker pink spots.

The first part of that sentence has caught my interest. And I have two questions:

1. Does that imply that there is somesort of (symbiotic or other) relationship between the (unnamed) fungus and the eucalypt? That would be quite an interesting relationship with the fungus caught in the middle.

2. Attached is also a picture from French Island (near Philip Is. in Vic). I saw a number of the flowers growing among these trees. I'm told that the trees in the picture are tea trees. Is that so? Are tea trees eucalypts? In otherplaces I've seen them (eg. Cathedral Ranges, Cobbobonee SF near Portland) I've seen them near different types of trees (I'm too ignorant to state which "types"). Does this mean that they don't exclusively require eucalypts?

Edited February 21, 2007 by Pala

[Prophet]

yeah its an interesting one. I have seen them in area where not many eucalyptus are present. Maybe the fungus is more important rather than a certain type of tree. I don't know how much research has been done on it. Its hard to say as eucalyptus roots can travel quite a distance and i haven't really seen any in areas where there are no eucalyptus at all. I suspect they can live without Eucalyptus though with certain other trees where the required fungus is present. I used to be an orchid enthusiast myself, i still like them and have a few growing around the place. I was always looking for natives out in the bush both terrestrial and epiphytic.

[tonic]

Hi there,

Will try and answer as many of your queries here as I can, will start by saying that Tea Trees are not Eucalypts they are a different genus [Leptospermum] but are infact in the same family MYRTACEAE. Eucalypts are Eucalyptus. As for the Dipodium puctatum not growing near the host species, well Eucalyptus spp. are known for their extensive root runs and for example a rare and vulnerable Eucalyptus camfeldii from the sydney region has been known to have extensive lignotubers up to a staggering 20m across!

The symbitioc fungus would most probably be Mycorhizza, but will do a bit of research on this because this has got me interested, am fairly certain there is a common Mycorhizza associated with Eucalyptus sp. I'd say it is quite possible for them to grow in association with other types of Mycorhizza but will do some research on this too. I usually see Dipodium puctatum growing near Eucalyptus spp. and sometimes the close allies Angophora spp. & Corymbia spp. and sometimes not.

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Dipodium punctatum is a leafless saprophyte which although very desirable is not amenable to cultivation as it requires a certain fungus relationship [What is this mysterious fungus?] to live successfully & also (a "mycoparasitic" orchid)

saprophyte:

an organism deriving its nourishment from dead organic matter and usually lacking chlorophyll. cf. parasite.

ah-ha! So this would explain why it feeds on Mycorhizza [just found this out]

Hope this helps a bit

And a note to prophet, I don't like to preach but you really shouldn't collect wild orchids from the bush as many of them are protected species and have been collected heavily which has put them in a vulnerable position

Edited February 24, 2007 by tonic

[PD.]

I saw one of these when on a beautiful trip to the east coast just before christmas.

I found it on a path almost identical to your second pic Pala.

here she is anyways.

[Pala]

Dipodium punctatum is a leafless saprophyte which although very desirable is not amenable to cultivation as it requires a certain fungus relationship [What is this mysterious fungus?] to live successfully & also (a "mycoparasitic" orchid)

saprophyte:

an organism deriving its nourishment from dead organic matter and usually lacking chlorophyll. cf. parasite.

ah-ha! So this would explain why it feeds on Mycorhizza [just found this out]

Hope this helps a bit

That was very infomative. Thanks!

Most of the flowers I saw near the Leptospermum were growing near one another which supports your suggestion that there might have been a eucalpyt root that had spread into that area.

So, if I understand correctly, the D. punctatum feeds on dead Mycohizza matter. If so... that implies a plant feeding off fungi, which looks very interesting since generally it is the fungus which feeds off dead organic matter.

Is mycoparasitic a real term, or just made up? Either way it does describe this very interesting relationship.

Prophet: To be honest I've only recently begun to notice wild orchids. Now I'm just waiting expectantly for spring to (hopefully) see them in force.

PD: Nice pic. The specimen shown seems to be much more mature than most of the ones I've seen.

[tonic]

It uses whatever the mycorrhiza uses as food, for example, decaying leaves, humus, ect; it is parasytic on the mycorrhiza, and the mycorrhiza lives in symbiosis with the Eucalyptus sp. to help control pests ect; and possibly has nutritional benefits for the host tree?

A very interesting system of life I would say, what with having three lifeforms all living symbiotically and relying on one another

Yes mycoparasite is real term, usually associated with Fungi though for example:

mycoparasite: a fungus parasitic on another fungus.

& here is the definition of mycorrhiza

mycorrhiza: a mutualistic or weakly pathogenic association of a fungus and the roots of a plant. There are a number of types, some of which are: ectomycorrhiza, where the fungus is on the surface of the roots and forms a Hartig net; endomycorrhiza, where the fungus invades the cells of roots where it is frequently confined to well-defined layers; ectendomycorrhiza, where there is a Hartig net but the fungus also penetrates the root cells; and vesicular arbuscular, where the hyphae in the cortical cells of the root may be coiled or branched. pl. mycorrhizae.

Edited February 26, 2007 by tonic