Monday 22 April 2019

Non-photosynthetic plants

You don't see many non-photosynthetic plants, which is probably a good thing.  I am not talking about fungi, they are not plants.  I am talking about flowering plants that don't photosynthesize.

The first time I saw a non-photosynthetic plant I was a teenager.  We had done a hazard reduction fire and a few weeks later a stem appeared in the parched ground.  It grew no leaves, only a flower stalk.  The flower stalk reached about 5 or 6 feet tall then opened into flowers.  It was a native orchid.  It was beautiful, I had never seen one before and have never seen one since.

Broomrape flowers
Most people know that green plants use photosynthesis to make energy, and that albino plants quickly die, so non-photosynthetic plants need some other way to gain energy.  Apparently non-photosynthetic plants are either parasites which directly feed off other plants, or they are indirect parasites through being myco-heterotrophs (feed off fungi) the fungi usually feeds off other green plants. 

Non-photosynthetic plants is a fascinating topic.  Sometimes this is a symbiotic relationship between the non-photosynthetic plant and the fungi, often the fungi gets nothing out of the deal.

Some non-photosynthetic plants don't have any above ground parts until they flower.  Others have stems and things above ground.
Non-photosynthetic plants sometimes have no above ground parts other than flowers
Last year I found a non-photosynthetic plant.  I hoped it would be an orchid, so I kept going back to check on it until it flowered, but it wasn't an orchid.  It was something I had never seen before.  I showed someone who identified it as a 'broomrape'.
Broomrape

Broomrape are plant parasites, in Australia there are three species.  I am not sure which this was, I have narrowed it down to two possibilities.  None of them have been recorded here, but two of the species have been recorded an hour or two from here.
Broomrape growing among grass

Branched broomrape (Orobanche ramosa) is a noxious weed that must be destroyed and reported.  It represents a serious threat to grain crops and has never been reported in this part of the country.  After looking at pictures on the internet and reading descriptions I am pretty confident that this plant was not branched broomrape.

Clover broomrape (Orobanche minor) is a minor agricultural pest, but not considered too much of a problems in Australia.  I don't think it needs to be destroyed and reported (I may need to double check this).

Native broomrape (Orobanche cernua var. australiana) is, as far as I can tell this is very rare and almost extinct.  Being native and rare it is not to be destroyed.
Non-photosynthetic broomrape

The plant is an annual that has long since died and disappeared.  If you can tell from my pictures what species of broomrape it is I would love to know.  Or if you have a simple way to tell between the two species please let me know, if it flowers again next year I will have a closer look.

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