Garden News Blog

Adventures in Fieldwork

We collected at the end of a harrowing road today – I’m not sure that our car rental agency knew what they were getting into with us! The habitat on the road to the Montagne des Sources Preserve was a mix of high maquis and rain forest on ultramafic soils. I still have not quite gotten used to seeing so many different gymnosperms in a tropical forest. Their presence and that of the gymnosperm-looking flowering plant family, Casuarinaceae, is evident in the canopy shot above. We saw quite a few plant species that were new to us today. One of the most interesting was the parasitic plant, Daenikera corallina (Santalaceae).

This is a truly parasitic plant meaning that it does not make its own food by converting the energy of the sun via photosynthesis. Instead, it steals the products of photosynthesis (primarily sugar) from other plants. Thus, Daenikera corallina does not have chlorophyll and is therefore not green. The only part of D. corallina that occurs outside of the plant it is parasitizing is its flowers and the stalk and branches on which they are borne (i.e. the inflorescence, which after fertilization develops into fruits in an infructescence).

Another interesting genus of which we have now seen several species is Scaevola in the Goodeniaceae. I first saw this genus on the island of Molokai in Hawaii and it has stayed with me because of its beautiful, strongly asymmetrical flowers.

The family Epacridaceae is now recognized within the blueberry family, Ericaceae. This formerly recognized family sometimes resembles what you would think of as a typical blueberry family member, but more often stretches the morphological limits of the Ericaceae. One such example is the Dracophyllum sp. that we saw today.

If you are a fan of tropical fruits, the fruit below might seem familiar to you. It is a Montrouziera sp. (Clusiaceae), a genus related to mangosteen (Garcinia mangostana, also in the Clusiaceae). This family is often characterized by having yellow sap, which you can see exuding from the bark slash in the picture below.

On our lunch break, Danielle sat down right next to two carnivorous plants and thus was the first person on our trip to see the pitcher plant, Nepenthes vieillardii (Nepenthaceae). The other animal-eating plant was Drosera neocaledonia (Droseraceae), a sundew. We have both pitcher plants and sundews in the flora of eastern North America – in the eastern US the pitcher plants are members of the genus Sarracenia (Sarraceniaceae), but sundews are in the same genus all around the world: Drosera.

Speaking of Danielle… she was the unlucky person who “got” to carry the Semecarpus atra samples down the mountain to me in Yahoué the other day. She had hiked ahead with one of our guides and the guide recognized Semecarpus and collected it for me. The only problem was that the guide did not know that Semecarpus causes a nasty rash much like poison ivy (Toxicodendron radicans). A few days later we found out that Danielle is just as allergic to Semecarpus as she is to poison ivy!

Susan Pell is the director of science at BBG, where she studies the evolutionary relationships of the cashew family. She holds a PhD in plant biology and teaches continuing education and training courses in genetics, angiosperm morphology, and systematics.

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Image, top of page:
Bourail forest canopy
Bourail forest canopy. Photo by Susan Pell.
Daenikera corallina
Fruit of the parasitic plant, Daenikera corallina. Photo by Susan Pell.
Scaevola beckii
Habit (left) and flowers (right) of Scaevola beckii. Photo by Susan Pell.
A very unusual blueberry family member, Dracophyllum sp. (formerly Epacridaceae). Photo by Susan Pell.
Clusiaceae Montrouziera
Clusiaceae Montrouziera sp. Photo by Susan Pell.
carnivorous plants
Two carnivorous plants living side by side: the pitcher plant Nepenthes vieillardii (left) and the sundew Drosera neocaledonia (right). Photo by Susan Pell.
Semecarpus rash
Danielle’s Semecarpus atra rash. Photo by Susan Pell.