''Pachypodium baronii'', the Madagascar palm or bontaka, is a flowering plant in the family ''
Apocynaceae
Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...
''. It has the habit of a robust
shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...
with a spherical or bottle-shaped trunk. It has several cylindrical branches at the top.
This plant is endemic to
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, where it grows in open
deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
forest on
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
calcareous
Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.
In zoology
''Calcareous'' is used as an adje ...
rock and
granite
Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
or
gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...
on the western side of the island at low elevations. It is known in Madagascar as "Bontaka". It is also endemic from
Befandriana Nord
Befandriana-Avaratra (literally North Befandriana; also Befandriana-Nord) is a city and urban commune (commune urbaine; mg, kaominina) in northern Madagascar. It belongs to the district of Befandriana-Nord, which is a part of Sofia Region. The ...
to
Mandritsara
Mandritsara is a city and commune (commune urbain, mg, kaominina) in northern Madagascar. It belongs to the Districts of Madagascar, district of Mandritsara District, Mandritsara, which is a part of Sofia Region. The population of the commune w ...
.
Constantin and Bois first described ''Pachypodium baronii'' as a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Pachypodium'' in 1907.
Morphology
Habit
''Pachypodium baronii'' is a robust, globose (spherical)- to bottle-shaped
shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...
in habit. Its trunk is subglobose, not quite globose or spherical, mostly narrowed at the base with dimensions of in length by by . At the top of the
trunk, it abruptly narrows into one or several cylindrical
branch
A branch, sometimes called a ramus in botany, is a woody structural member connected to the central trunk (botany), trunk of a tree (or sometimes a shrub). Large branches are known as boughs and small branches are known as twigs. The term '' ...
es that are to by by in diameter, tapering to to in diameter.
''Pachypodium baronii'' typically grows to high. Its bark is colored pale grey or grey-green and is smooth, but sometimes retains remnants of leaf scars.