Friday, January 22, 2010

Yellow Rattlepod

Crotalaria mitchellii
Family: FABACEAE

Crotalarias are plants of high summer, just starting to look their best now.
With a lifespan of just a few years, these are pretty, drought-hardy plants, suited to sunny flower gardens. They are easy to propagate from seed.





These showy spikes of bright yellow pea-flowers are followed by inflated seedpods. As they ripen and dry out, the seeds come adrift from their moorings inside and make a musical rattling sound when bumped or shaken.



There are two subspecies. The subspecies mitchellii (shown above) is more common on sandstone than on our basalt soils, though it does grow on red basalt ridges where the soil is light and well-drained.
The subspecies laevis has leaves no wider than 1.5cm, and grows only in the inland. It is a drought hardier plant, and more tolerant of heavier soils. Both subspecies can be found in our district.

Like many species of Crotalaria, they have been suspected of poisoning cattle, pigs, and horses. Feeding tests, however, show that the different species of Crotalaria vary widely in their toxicity levels. Tests with this one have failed to produce any signs of harm, so I feel we can grow them with a clear conscience.



Butterflies like this one - pretty little things with blue on their upper wings - take a great interest in our rattlepods. We suspect them of being a butterfly called forget-me-not (Catochrysops panormus platissa) - but are not great at butterfly ID! Can anyone help?

4 comments:

Lesley said...

I think you're right about the butterfly. Great picture!

Patricia Gardner said...

Thank you Lesley - actually it's my husband who takes photos of that quality!
We find photography is a good way to get a close look at a butterfly. I does keep it still while we get a good look - and we can blow it up on a screen to see the details.
Trish

Tom said...

Hi Trish,

I think that is a Cycad Blue butterfly - Theclinesthes onycha
(ref http://www.brisbaneinsects.com/brisbane_blues/CycasBlue.htm) Have a look and see if you agree. I found some Crotalaria in flower the other day under the powerlines on Mt Petrie - I think C grahamiana rather than the native sp. As it was a most eye catching plant I have taken some cuttings and will look for some seed pods in a few weeks to propagate it for our property.

Patricia Gardner said...

A cycad butterfly - now that's an interesting thought. The only cycads up here are planted ones, as they are not native to the district - but I do have one in the garden. How interesting if the range of the butterfly is spreading thanks to gardeners!
Trish