Comesperma is an Australian genus (mainly in WA), which belongs to the Polygalaceae (Milkwort) family that is widespread in other countries. The name Comesperma means 'hairy seed", which relates to the seeds bearing tufts of hair. They are climbers or small wiry shrubs (that are often grazed by kangaroos). I am intrigued by their small 'upside down pea' flowers: an evolutionary adaption to attract native bees that pollinate adjoining pea plants.
 Comesperma interregnum a climber |  Comesperma volubile a climber |  Comesperma calymega a shrub |  Comesperma scoparia a shrub |
On closer inspection, it is obvious that Comesperma flowers are very different from peas.
When a bee lands on a pea flower, its legs part the wing petals to reveal the underlying stamens and pistil.
There is little internet information on Comesperma pollination apart from them being pollinated by native bees, and that the flowers use secondary pollen presentation.
Comesperma flowers are quite strange. Two of the five sepals comprise the coloured 'wings' (like an upside-down Donkey orchid - another pea flower mimic), and the petals form a pouch-like 'keel' enclosing the stamens and pistil) with two upright petals at the end.
When a bee lands on a pea flower, its legs part the wing petals to reveal the underlying stamens and pistil.
There is little internet information on Comesperma pollination apart from them being pollinated by native bees, and that the flowers use secondary pollen presentation.
Comesperma flowers are quite strange. Two of the five sepals comprise the coloured 'wings' (like an upside-down Donkey orchid - another pea flower mimic), and the petals form a pouch-like 'keel' enclosing the stamens and pistil) with two upright petals at the end.
 Typical pea flower |  Comesperma scoparia front view |  Comesperma scoparia rear view |
On close inspection the story gets even stranger.
White UV fluorescent patterns lead the pollinator to a small hole between the keel and outer petals. What could be inside?
It was no mean effort cutting into the tiny keel without destroying its contents, so the following images are a bit ragged.
First Comesperma scoparia.
The style appears to grow up in a curve, pushing the cup-shaped stigma into anthers which are crowded at the top of the keel. This loads pollen into the cup shaped stigma ready for contact with a pollinator's tongue which presumably is poked into the entrance. The last image shows that the style had straightened out during dissection. Blowed if I know, but perhaps the style is held under tension inside the keel. Could it poke out after contact with the insect's tongue? The active part of the stigma is a patch on the side of the style underneath the stigma cup.
White UV fluorescent patterns lead the pollinator to a small hole between the keel and outer petals. What could be inside?
It was no mean effort cutting into the tiny keel without destroying its contents, so the following images are a bit ragged.
First Comesperma scoparia.
The style appears to grow up in a curve, pushing the cup-shaped stigma into anthers which are crowded at the top of the keel. This loads pollen into the cup shaped stigma ready for contact with a pollinator's tongue which presumably is poked into the entrance. The last image shows that the style had straightened out during dissection. Blowed if I know, but perhaps the style is held under tension inside the keel. Could it poke out after contact with the insect's tongue? The active part of the stigma is a patch on the side of the style underneath the stigma cup.
 Comesperma scoparia keel petal from above |  Pistil and stamens crowded inside keel |  Straightened pistil |
Comesperma volubile My attempt as dissecting Comesperma volubile shows that the stamens are attached as a band to the interior of the keel.
My next challenge is to see them being pollinated.
Curious little plants!
My next challenge is to see them being pollinated.
Curious little plants!
 Comesperma volubile keel |  Curved style and some of the stamens |  Stamens on one side of keel interior |