69 (March/April 2002)
Begonia venosa in the
Chapada Diamantina, Bahia, Brazil
by Jacques Jangoux
I went on vacation in July 2001 with my wife and my
five and a half year old little girl in the Chapada Diamantina mountain
range in western Bahia State in Brazil (My older son, 19, isn't interested
in nature. His interests are his computer, the internet, his rock group --
he plays the guitar -- and NBA basketball).
The region, about an hour from Salvador by small
plane, owes its name to the fact that it is rich in diamonds; some hand
mining is still done, although the use of machines has been prohibited as
the region is now a National Park. Chapada means a plateau covered with
low vegetation. During a first walk my wife spotted a few sterile plants
of a begonia. Later, on a long walk alone, I found a beautiful flowering
plant of it growing in full sun in sandy debris among rocks.
I even saw one growing next to a cactus, but it was in
an inaccessible place and I didn't have a lens long enough to get a good
photograph of it. Actually there seemed to have been 2 species growing
together. On the return from a long hike, when I was already tired, I
noticed that one plant had both peltate-orbicular and cordate-orbicular
leaves, on different stems. I found it strange but, as I was tired, I
didn't take a picture.
I collected young plants, not knowing that they were
different; now that they are growing, I have plants with each type of
leaf, the peltate ones being glabrous, the cordate being
stellate-tomentose. Looking in Begoniaceae by Lyman B. Smith et al.
(Smithsonian Contributions to Botany, number 60), I found that the peltate
form is probably B. umbraculifera; the other form shown in the
cover photograph is most probably B. venosa. So the plant with the
two types of leaves[not photographed] was two plants growing together?
My young plants initially grew well, then some had
burn spots on their leaves, some died, and the ones that survived stopped
growing or are growing very slowly. I don't know what the problem is as
the amount of sun they receive is the same as before and where they grow
in nature the sun is very strong. Here in Belem I am close to the Equator,
though. Maybe someone watered them in full sun? Some are still alive, and
I am fighting hard for them not to die.
Now, written a few days later, there is good news.
Lately, I have given them less sun and more water, and they seem to have
improved. Even in their dry habitat they probably get underground humidity
from under the rocks.
For those of you with a computer, here are a couple of
URLs on the region: http://www.hoteldelencois.com/