Pale - Dark Yellow
This member of the Pedaliaceae family was described by Werner Rauh in 1996.
It's from Madagascar, growing in well-drained soil with lots of water
and sun. The stems reaches for two meters with a base of 14 centimetres. The flowers are
pale to dark yellow, and it
can be reproduced by cuttings as well.
The genera is named for the
Uncarina tribe of Madagascar. The species is named after Walter
Röösli, a Swiss optician and lover of botany, travelling Madagascar.
There are two very distinct leaf forms on
roeoesliana, and in
the last couple of years, they have been mixed. Doesn't exactly make it
easy to ID your plant!
I found this informative piece from: Chuck Hanson - Arid Lands
Nursery. An interesting feature of this genus is its pollination
strategy. Although the sexual parts of the flowers are apparently
normal, the anthers never shed pollen. If one tries to pollinate the
flowers of an Uncarina, the usual method of using a small brush to
transfer pollen doesn't work. There are several families of pollen
eating beetles. Beetles are not as skilful fliers as are bees, moths,
etc., therefore they need a good landing platform so they can feed
without flying. The corolla limb of Uncarina is a perfect landing
platform. Some even have nice "runway" markings such as
stripes and dark floral tube markings. Remember that these flowers are
oriented horizontally. The stigma has two lobes, one upright and one
hanging down into the tube, partially blocking ingress. The beetle
pushes past this stigma lobe to get to the anthers. Each anther has a
lobe that hangs down into the floral tube. The beetle begins feeding on
this lobe. As it bites into the lobe a slit pore above the lobe opens
and pollen the consistency of toothpaste is deposited on the head and
thorax of the beetle. When the beetle exits the flower the stigma lobe
offers no resistance. As the beetle enters another flower and pushes
past the lower stigma lobe the upper stigma lobe is moved down on top of
the beetle and scrapes the pollen off. Pollination!