Habit Pachypodium baronii is a robust, globose (spherical)- to bottle-shaped
shrub 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
branches 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.
Branchlets are to in length by in width. They are covered with paired often curved
spines that measure long to in diameter at the base of the branchlet. Its
basal (lower) part of the branchlet is conical and laterally compressed at 0.33 to 0.66 times the spine's length. The spines are often red and
pubescent, hairy when young, turning medium to dark brown and glabrous and smooth.
Leaves The
leaves of
Pachypodium baronii are confined to the apices of the branchlets. The leaves are petiolate, meaning that they bear a
stalk that attaches to the
stem and to the leaf blade. The
petiole is a pale reddish-green about long. It is pubescent, or hairy-like. The blade is coriaceous, leathery, and medium green. It has a midrib that is above pale green and shiny and beneath pale and glaucous, smooth without hairs. The pale green midrib and dark green reticulate venation is visible when the blade is fresh. When dried, the blade is papery, ovate to obovate or narrowly so, and 1.4 to 3 times as long as it is wide. Therefore, the leaf measures to in length by to h). It is acuminate, tapering gradually to a sharp point, to apiculate, ending abruptly with a sharp, flexible tip at the apex and wedged-shape or
cuneate to rounded at the base. The leaf's margin is revolute, rolled backward from the tip or margins to the undersurface, glabrous to sparsely pubescent above. Beneath it is pubescent especially on midrib and secondary veins as well as the impressed of venation. As well, underneath the leaf, the midrib and secondary veins are very prominent. The secondary veins are in 15 to 30 pairs, straight, upcurved at the apex, and forming an angle of 45–90° with the costa--
the rib, ridge, or especially the mid-rib, for instance, of a leaf. The tertiary, or third level of venation is reticulate, netted or showing a net like structure or pattern.
Inflorescence The
inflorescence of
Pachypodium baronii is pedunculate, having a main axis to flower stalk. The inflorescence is congested, measures 16 cm (inch) by 40 (inch) in length by 40 cm (1.58-inch) to 4.5 cm (1.77-inch) to 12 cm (0.47-inch), and have 3 to 17 flowers. The inflorescence's peduncle, the stalk of an inflorescence or a stalk bearing a solitary flower in a one-flowered inflorescence, is pale green and terete, cylindrical but usually slightly tapering at both ends. It measures 7 mm (0.276-inch) to 20 mm (0.787-inch) in length by 4 mm (0.157-inch) to 6 mm (0.236-inch). The peduncle, as well, is glabrescent. The
pedicels are pale reddish-green, 8 mm (0.315-inch) to long, and sparsely pubescent and hairy. The
bracts of
P. baronii are oblong and 2 to 3.5 times as long as wide, thus 5 mm (0.197-inch) to 11 mm (0.433-inch) in length by 2 mm (.078-inch) to 2.5 mm (0.098-inch). The bracts are longer than the
sepals and are pubescent, hairy outside, glabrous, smooth, without hairs inside.
Flowers The sepals of
Pachypodium baronii are no different than most sepals in other flowering plants (
angiosperms) in forming an outer floral envelope. In
P. baronii's case, the sepals are dark green, connate at the base for about 0.2 mm (.008 (0.098-inch), persistent until maturity of the flower, and
ovate or narrowly so. They measure 1.5–2.5 times as long as they are wide at 2.5 mm (inch) to 6 mm (inch) in length by 1.5 mm (0.059-inch) to 2.5 mm (0.098-inch). They are acuminate at the apex and glabrous, smooth, to sparsely
pubescent, slightly hairy, outside and glabrous inside.
Corolla The collective term for all the
petals of a flower or the inner whorl of the
perianth; the corolla of
Pachypodium baronii is limb and crimson with a corolla tube. The basal part of the corolla tube, the part of the corolla where the petals are united to form a funnel shaped cylinder, is pale green, whereas the upper part is part greenish-red outside and inside pale yellow or pale green. Inside these colors are shaped like a star or ring in pattern. They are surrounded by a dark red throat, measuring 2.5 cm (inch) to 4 cm (inch) long in the mature bud. The corolla tube forms a comparatively wide and broadly ovoid, broad and rounded at the base and tapering toward the end, head that measures 0.4 to 0.5 times the tube's length, thus, at 1 cm (0.39-inch) to 1.9 cm (0.75-inch) long by 0.7 cm (0.28-inch) to 1.1 cm (0.43-inch) wide. At the apex, the bud is acuminate, tapering gradually to a sharp point, to obtuse, having a blunt or rounded tip. Whereas it is (I) glabrous or sparsely pubescent to often partly pubescent outside, inside it is (II) glabrous on the part of the lobes covering the bud and glabrous for 6 mm (0.236-inch) to 7 mm (0.276-inch) from the base. A pubescent belt located inside the corolla tube is 4 mm (0.158-inch) to 7 mm (0.276-inch) below the insertion of the
stamens, the male
reproductive organ of a flower, to the mouth. The mouth is more densely pubescent and hairy. The corolla tube is 4.4 to 6 times as long as the
calyx, which is 1.13 to 1.22 times as long as the corolla lobes. Therefore, the corolla tube is 15 mm (inch) to 23 mm (inch) long. Its basal part is almost
cylindrical, but often conically widened at the base. It is 0.39 to 0.44 times the length of the entire tube at 7 mm (0.276-inch) to 9 mm (0.354-inch) long by 2 mm (0.079-inch) to 4.8 mm (0.189-inch) wide. The upper part is almost cylindrical at 8 mm (0.315-inch) to 14 mm (0.551-inch) long. It slightly narrows at the mouth to be 3 mm (0.118-inch) to 4 mm (0.158-inch) wide. The corolla lobes are obliquely and broadly obovate, egg-shaped and flat with the narrow end attached to the stalk, at 0.8 to 0.9 times as long as the tube, hence measuring at 1.35 to 1.6 times as long as it is wide at 15 mm (0.591-inch) to 19 mm (0.75-inch) long by 11 mm (0.43-inch) to 17 mm (0.67-inch) wide. The lobes are rounded at their apex and
ciliate at the edge, or margin.
Stamens With an apex 4 mm (0.158-inch) to 4.5 mm (0.177-inch) below the mouth of the corolla tube, ''Pachypodium baronii's
stamens are inserted at 0.47 to 0.6 the length of the corolla tube. It measures at 1.0 cm (0.394-inch) to 1.4 cm (0.551-inch) from the base. The stamen is the male reproductive organ of a flower where it usually has a filament and, at least, an anther. A filament is usually thin short or elongated stalk of the stamen that carries the anther at the upper end; whereas the anther is the part of the stamen that bear the pollen. In baronii,'' the anthers are very narrowly triangular at 5 to 6 times as long as wide, measuring 6 mm (0.236-inch) to 6.5 mm (0.256-inch) in length by 1.0 mm (0.039-inch) to 1.3 mm (0.051-inch) wide. They are pubescent inside at the base of the connective, the
sterile part of the anther as opposed to the
theca, which is the part of the anther that carries
pollen, and are just below where the anther occurs with the
pistil head, part of the female reproductive organ in a flower.
Pistil The pistil is the female reproductive organ of a flower that is composed of an
ovary and several free
carpels the style and the stigma. A carpel is the modified leaf that contains the ovules and has a style and a stigma on top. The style is the stalk-like portion that connects the stigma and the carpel or ovary; whereas the stigma, itself, is the top most receptive region of the style, commonly divided. In
Pachypodium baronii the pistil is 12.5 mm (0.49-inch) to 14.5 mm (0.57-inch) long. The ovary measures 2 mm (0.078-inch) to 2.5 mm (0.098-inch) long by 1.8 mm (0.071-inch) to 2.2 mm (0.87-inch) wide by 1.5 mm (0.059-inch) high. It is pubescent on the part not covered by the disk, a disk-like structure that secretes
nectar. In
P. baronii, the disk is composed of five unequal glands, where 2 or 2 pairs are fused partly or entirely. These glands are ovate and measure 1.7 mm (0.067-inch) to 2 mm (0.079-inch) high. They are rounded at the apex and are more than half as long as the ovary. The style is 9.3 mm (0.37-inch) to 11 mm (0.43-inch) long and sparsely pubescent. The pistil head is cylindrical and is at 1.0 mm (.039-inch) to 1.3 mm (0.51-inch) high. It is composed of an
obconical, inverted conical shape, basal part, which is 0.5 mm (0.020-inch) to 0.65 mm (0.26-inch) long by 0.4 mm (0.016-inch) to 0.5 mm (0.020-inch) wide. The pistil has a ring-shaped central part measuring 0.5 mm (0.020-inch) to 0.7 mm (0.028-inch) long by 0.6mm (0.024-inch) to 0.7 mm (0.028-inch). It has a stigmoid apex 0.1 mm (0.004-inch) to 0.2 mm (0.008-inch) by to 0.4 mm (0.016-inch). The ovules are approximately 50 in each carpel.
Fruit The fruit of
Pachypodium baronii is made up of 2 separate mericarps, the part of the ovary or
carpel that has one or more enclosed
seeds. Sometimes only one fruit develops with an angle of 45–180° at the base. Sometimes flowers and fruit are on the same
inflorescence. The mericarps are pale reddish-green with
longitudinal lines when fresh and when dried pale brown to pale greenish-brown to dark brown outside and whitish to very pale brown inside. The fruit measures 40 mm (1.58-inch) to 115 mm (4.53-inch) long by 10 mm (0.39-inch) to wide by 7 mm (0.28-inch) to 10 mm (0.39-inch) high. When the fruit is fresh it is either straight or recurved, obtuse to acute at the apex. It is pubescent and has a wall 1 mm (inch) thick.
Seeds The seed of
Pachypodium baronii is pale brown with margin medium brown when fresh. It is ovate to elliptic at 6 mm (0.236-inch) to 7 mm (0.256-inch) by 3 mm (0.118-inch) to 3.8 mm (0.150-inch). It is rounded at the apex, obtuse at the base, and has a margin that is revolute towards the hilar side. The testa is smooth. The coma is straw-colored and at 1 cm (0.39-inch) to 1.5 cm (0.59-inch) long. The
embryo is whitish at 5 mm (0.197-inch) by 6 mm (0.236-inch) long. The
cotyledons are ovate and 1.14 to 1.2 times as long as it is wide at 3 mm (0.118-inch) to 4 mm (0.158-inch) long by 2.5 mm (0.98-inch) to 3.5 mm (0.138-inch) wide. They are rounded at the apex and cordate at the base with a
rootlet 0.6 to 0.8 times as long as the cotyledons at 2 mm (0.079-inch) to long by 1.0 mm (0.039-inch) to 1.8 mm (0.071-inch) wide. ==Ecology==