View source for Pachypodium baronii

{{Taxobox
| color = lightgreen
| name = ''Pachypodium baronii''
| image = Pachypodium baroni.JPG
| image_width = 150px
| regnum = [[Plantae]]
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Gentianales]]
| familia = [[Apocynaceae]]
| genus = [[Pachypodium]]
| species = '''''P. baronii'''''
| binomial = ''Pachypodium baronii''
| binomial_authority = Costantin & Bois
}}

'''Madagascar palm''' ('''''Pachypodium baronii'''''), also known as '''bontaka''', is a flowering plant in the Dogbane family ''[[Apocynaceae]]'' (which has been recently merged with Milkweed family ''[[Asclepiadaceae]]''). It has the habit of a robust [[shrub]] with a spherical or bottle-shaped trunk. It has several cylindrical branches at the top.

This plant is endemic to [[Madagascar]], where it grows in open [[deciduous]] forest on [[Mesozoic]] [[limestone|calcareous]] rock and [[granite]] or [[gneiss]] on the western side of the island at low elevations. It is known in Madagascar as "Bontaka". It is also endemic from [[Befandriana Nord]] to [[Mandritsara]].

Constantin and Bois first described ''Pachypodium baronii'' as a [[species]] of the [[genus]] ''Pachypodium'' in 1907. 

==[[Morphology (biology)|Morphology]]==
===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 20 cm (7.87 inch) to 40 cm (15.75 inch) in length by 20 cm (7.87 inch) by 50 cm (19.69 inch). At the top of the [[trunk]], it abruptly narrows into one or several cylindrical [[branch]]es that are 30 cm (11.81 inch) to 50 (19.69 inch) cm by 4 cm (1.58 inch) by 8 cm (3.15 inch) in diameter, tapering to 3 cm (3.15 inch) to 4 cm (1.58 inch) in diameter. 

''Pachypodium baronii'' typically grows to 1 m (3.28 feet) to 3.50 m (11.48 feet) high. Its bark is colored pale grey or grey-green and is smooth, but sometimes retains remnants of leaf scars. Branchlets are 1.5 cm (0.59 inch) to 7 cm (2.76 inch) in length by 0.8 cm (0.32 inch) to 1.5 cm (0.59 inch) in width. They are covered with paired often curved [[spine (biology)|spines]] that measure 2 mm (0.079 inch) by 9 mm (0.354 inch) long to 1 mm (0.039 inch) to 4 mm (0.158 inch) in diameter at the base of the branchlet. Its [[anatomical term of location|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 [[leaf | leaves]] of ''Pachypodium baronii'' are confined to the [[apex | apices]] of the branchlets. The leaves are petiolate, meaning that they bear a [[stalk (botany)|stalk]] that attaches to the [[Plant stem|stem]] and to the leaf blade. The [[Petiole (botany)|petiole]] is a pale reddish-green about 3 mm (0.118 inch) to 25 mm (0.985 inch) 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 3 cm (1.18 inch) to 18 cm (0.71 inch) in length by 1.4 cm (0.55 inch) to 9 cm (0.35 inch). 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 [[pedicel]]s are pale reddish-green, 8 mm (0.315 inch) to 23 mm (0.906inch) long, and sparsely pubescent and hairy. The [[bract]]s` 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 [[sepal]]s and are pubescent, hairy outside, glabrous, smooth, without hairs inside. 

====[[Flower]]s====
The sepals of ''Pachypodium baronii'' are no different than most sepals in other flowering plants ([[angiosperm]]s) in forming an outer floral envelop. 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 [[petal]]s 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 [[stamen]]s, the male [[reproduction | 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 (botany)|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'' [[stamen]]s 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 [[infertility|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 (plants)|ovary]] and several free [[carpel]]s 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 0.3 mm (0.012inch)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 [[seed]]s. 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 20 mm (0.79inch) 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 [[root]]let 0.6 to 0.8 times as long as the cotyledons at 2 mm (0.079 inch) to 2.5 mm (0.098inch) long by 1.0 mm (0.039 inch) to 1.8 mm (0.071 inch) wide.

==[[Ecology]]==
''Pachypodium baronii'' is found on three different substrate, where two are similar and one is not. It can be located on mainly steep gneiss but sometimes granite rocks ([[metamorphic]] basement) and Mesozoic calcareous rock. "metamorphic basement" means a [[geology|geological]] complex of undifferentiated [[igneous]] and [[metamorphic]] rocks where the rocks themselves have altered their composition, texture, or internal structure through extreme heat, pressure, and the introduction of a chemical. Granite and gneiss, in this condition of being undifferentiated, tend to have an acidi [[pH]] level; whereas calcareous rock tends to be more basic. This flexibility in substrate demonstrates a less specialized geological environment. These steep rocks are often located in low open dry, [[xeric]] deciduous western [[forest]]s where they take advantage of micro-environments suitable for [[succulents]]. Micro-environments means a delimited convergence of very localize [[landscape]] and [[climate]] conditions that are in stark contrast to the larger vegetative [[climate | climatic]] environmental zone. ''Pachypodium baronii'' prefers open sunlight but will tolerate some indirect light conditions because they inhabit open deciduous forests. They grow at an [[altitude]] between 300 m ( feet) to 1200 m ( feet) . Other vegetative types, often site indictors of micro-environments, are associated with ''P. baronii'' in habitats, such as ''[[Pachypodium sofiense]]'' [[Apocynaceae]], ''Uncarina'' sp., (Pedialaceae) ''[[Aloe]]'' ''bulbillifera'' (Asphodelaceae), ''[[Euphorbia]]'' ''milii'' (Euphorbaceae), ''[[Kalanchoe]]'' ''gastonis-bonieri'' (Crassulaceae), and ''Urera'' sp. (Urticaceae).

===[[Cultivation]]===
The substrate for ''Pachypodium baronii'' in cultivation is an acidic loose peat mixed with gneiss sand at a pH level of 4. [[Temperatures]] from spring to autumn, day and night are respectively 12°C (53.6 °F) to 40°C (104 °F). In the [[winter]], night and day temperatures should range from 12°C (53.6 °F) to 20°C (68 °F) or more. It will after four years of growth flower profusely in the spring. As well, it needs a larger pot size than other ''Pachypodium'' species. It water regime is to water a lot during growing season and very little during the resting time only to prohibit trying out of roots. Propagation is by seeds.

==Literature==
The [[botany | botanist]] team qua ''team'' of Costantin and Bois is not listed in the publication section of the [http://www.huh.harvard.edu/databases/ Online Database of Harvard University Herbaria.] so other records will need to be examined. The Harvard University [[herbarium | Herbaria]] does; however, list each botanist separately so that it is easy to discern their identities. 

Note: Name of Botanist and some full names of journals is taken from the [http://www.huh.harvard.edu/databases/ Online Database Harvard University Herbaria.]

Again Harvard University Herbaria does not list "Constantin & Bois" as a team who worked together. Yet each member; however, is listed separately.
*"Constantin" is the ''[[author]] name'' for ''Julien Noel Costantin''. "Bois," likewise, is the name for ''Desire Georges Jean Marie Bois''. As a team, they published in 1907 ''Pachypodium baronii'' as a species of ''Pachypodium'' within the journal abbreviated "Ann. Sc. Nat." 
*The author known as "Perrier de la Bâthie", known by his full name ''Joseph Marie Henry Alfred Perrier de la Bâthie'', published an account of the taxon in "Bulletin de la Société Botanique de France" 81: 301 (1934) in 1934. 
*The botanist ''Marcel Pichon'', author name "Pichon," gave an account of the species in the abbreviated [[journal]] name ''Mem. Inst. Sc. Madag'', sér. B, 2: 123 (1949) (all three as ''baronii''). 
*Most recently ''Friedrich Markgraf'' in 1976 gave [[definition]] to ''P. baronii'' in "Fl. Madag." fam. 169: 289(1976). 
The [[Species]] [[Type]] is : Madagascar, sin. loc., ''Baron'' 5874 ([[holotype]] P; [[isotype]] K). fig. 1, p. 11; Map 1, p. 12; Plates 2-4, opposite p.16.

Along this history of ''Pachypodium baronii'' a variety of the species was published in 1924 by the name ''Pachypodium baronii'' var. ''erythreum.'' by the botanist ''Henri Louis Poisson'', author name "Poiss.", within the abbreviated name for the journal "Bull. Acad. Malgache." sér. 2, 6: 166, pl. 10 (1924). Its Species Type: Madagascar, Antsiranana, Upper Sofia R., Antsakabary, ''Perrier de la Bâthie'' 15082 (holotype P). ''Rapanarivo et al.'' and apparently others have considered it a synonym for ''Pachypodium baronii.''

===External sources===
*Eggli, Urs. <u>Glossary of botanical terms with special reference to Succulent Plants</u>. with German Equivalents (British Cactus & Succulent Society: United Kingdom: 1993) and 
*TheFreeDictionary: terms 
*Rapanarivo, S.H.J.V., Lavranos, J.J., Leeuwenberg, A.J.M., and Röösli, W. <u>Pachypodium (Apocynaceae): Taxonomy, habitats and cultivation</u> "Taxonomic revision of the genus Pachypodium," S.H.J.V. Rapanarivo and J.J. Lavranos; "The habitats of Pachypodium species" S.H.J.V. Rapanarivo; "Cultivation" W. Röösli. (A.A. Balkema: Rotterdam, Brookfield, 1999) [Rapanarivo et al.]

{{pachypodium}}

[[Category:Apocynaceae]]
[[Category:Flora of Madagascar]]