Pedilanthus
macrocarpus
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This
species is a leafless stem succulent from
the Sonoran Desert of northwestern Mexico. This photograph is from the
central
Baja California Peninsula. One of the stems in this photos is cristate,
that is, the meristem has become a long and convoluted line rather than
a tiny globular cluster of cells.
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Pedilanthus
coalcomanensis |
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This
species was
discovered
in a remote mountain range in western Mexico in the 1930s.
Unfortunately,
the information on the herbarium specimen label was so vague that its
exact
location was unknown. We recently located a population of this species,
which
forms graceful small trees with large, colorful inflorescences, fuzzy
leaves
and tuberous roots. This photo was taken in the winter dry season.
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These
images were taken in the summer rainy season to show that this species
grows in one of the most strikingly seasonal tropical dry forests we've
ever visited. This area resembles a cloud forest in the rainy season,
but is baked dry for half of the year. Here, Pedilanthus coalcomanensis forms a
dense, shady stand.
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The
fuzzy leaves of Pedilanthus
coalcomanensis
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In
keeping with the very wet wet seasons of the area, the trunks of Pedilanthus coalcomanensis are
covered with dense mats of lichens, mosses, and epiphytes.
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The
inflorescences of Euphorbia (Pedilanthus) coalcomanensis are
spectacular. The bright green cyathia project from brilliant pink
bracts when the plant, as well as most of the surrounding forest, is
leafless and gray.
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This
image shows the male and female flowers projecting out of the green
cyathia of Euphorbia (Pedilanthus) coalcomanensis. Like so
many plants, we do not know what polliates the flowers of this
microendemic species. |
Pedilanthus
calcaratus |
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Pedilanthus
calcaratus is the most widespread of the woody treelets in the
genus. Plants
are often 2-3 meters tall with large, evergreen leaves in the southern
part
of the range, as in the photos below. Farther north, such as where the
specimen at left was
photographed
in Michoacán, the plants lose most of their leaves in the dry
season. |
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Pedilanthus
nodiflorus |
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The exposed
glands
on either side of each inflorescence become covered with fungi with
age,
darkening them and emphasizing the appearance of a cow's skull. |
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In Mexico's
Yucatán
Peninsula, this species is found in clearings in dense deciduous forest
just
inland from mangrove swamps. The small tree at left is a Cnidoscolus,
another member of Euphorbiaceae. |
Pedilanthus
finkii |
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The incredible
range
of life form and ecological tolerance of Pedilanthus reaches an
extreme
in P. finkii. This
species
grows in tall, wet tropical forest, where its leaves are covered with
lichens
and mosses. It grows as a shrub with stems that root in the moist leaf
litter
when they fall over. The plants in the population shown here grow in
cracks
and hollows in limestone in Oaxaca. |
Pedilanthus
tithymaloides |
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Pedilanthus
tithymaloides
has the widest range of all of the species, ranging from South America
to
Tamaulipas, Mexico, and the Caribbean. It varies somewhat in habit. In
Mexico,
it is most often a small shrub, such as the three individuals shown in
the
foreground in this image from southern Oaxaca where it grows in the
understory
of dense tropical dry forest. |
Pedilanthus
diazlunanus |
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One of the stem
succulent
members of the genus, this species is found only in a small part of
southern
Jalisco where it grows in rich and highly scenic tropical dry forest. |
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The
inflorescence of P. diazlunanus
is unusually short relative to its length.
Unlike
most species of Pedilanthus, it is probably pollinated by
insects rather
than hummingbirds. |
Pedilanthus
pulchellus |
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This beautiful
species
with a bright red-orange inflorescence was known only from a single
collection
from a mountain in Oaxaca in 1917, but there was some confusion as to
where
exactly it occurred. It had not been seen again until we located a
small
population in January 2003. |
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Like its relative
P.
calcaratus, this species grows in the shade of larger plants. We
found
it growing in rocky soil beneath very low, dense, seasonally dry
tropical
forest. |
Pedilanthus
tehuacanus |
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Most of the stem
succulent
species of Pedilanthus grow
on lowland plains, which are ideal areas for growing crops and building
cities. Pedilanthus tehuacanus occurs on the outskirts of the
city of
Tehuacan and may be in trouble as a result. |
Pedilanthus
palmeri |
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This species has
very
distinctive inflorescences that remind us of ducks. It grows in shady
forests
in western Mexico from Nayarit to Oaxaca. This population from Oaxaca
has
inflorescences that lose their bracts very early. |
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Like P.
pulchellus,
this species only loses its leaves under extreme conditions, whereas
other
species such as P. coalcomanensis lose their leaves each dry
season. |
Pedilanthus
connatus (Euphorbia colligata)
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In
at least one locality that we have visited repeatedly the plants seem
to be disappearing, but we aren't sure why.
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This
species is endemic to the rugged mountains of western Jalisco State,
where it often grows in shady canyons. This image shows the
particularly attractive cyathium of Euphorbia
colligata (P. connatus).
Male Euphorbia flowers are
extremely reduced, just a pedicel (lower stalk) and the stamen (the
anther plus its stalk). In this image, the pedicels of the male flowers
are white and the filaments (stalks) of the male flowers are red.
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This
image shows the yellow pollen in the male flowers, as well as the red
style of the female flower. The clear droplet in the middle of the
image is a drop of sweet nectar, which makes us think that some animal,
perhaps a humminbird, pollinates this pretty species.
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