Alantsilodendron Villiers, Bull. Mus. Natl. Hist. Nat., B, Adansonia 16: 65. 1994.
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https://dx.doi.org/10.3897/phytokeys.240.101716 |
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https://treatment.plazi.org/id/962A272E-F0C9-4A34-8154-30A8596F91E3 |
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scientific name |
Alantsilodendron Villiers, Bull. Mus. Natl. Hist. Nat., B, Adansonia 16: 65. 1994. |
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Alantsilodendron Villiers, Bull. Mus. Natl. Hist. Nat., B, Adansonia 16: 65. 1994. View in CoL
Figs 144 View Figure 144 , 145 View Figure 145 , 146 View Figure 146 , 160 View Figure 160
Type.
Alantsilodendron villosum (R. Vig.) Villiers [≡ Dichrostachys villosa R. Vig.]
Description.
Unarmed (weak thorns in one species) shrubs or small treelets (Fig. 144L View Figure 144 ), 1-5 m, much-branched from base, branches often plagiotropic; brachyblasts present, usually clothed in distichous or spirally arranged rows of persistent or caducous stipule bases. Stipules monomorphic, striate, ovate. Leaves bipinnate, extrafloral nectary between lower pair, and sometimes more distal pinnae; pinnae 1-7 pairs (10-50 in one species); leaflets 2-20 pairs per pinna (30-50 in one species), linear to ovate, base truncate. Inflorescence usually a capitulum (Fig. 145I View Figure 145 ), occasionally a condensed spike, usually solitary in leaf axils of new growth or more often on short shoots, flowers usually lacking a pseudopedicel; bracteoles subtending individual flowers carinate, 1-nerved; inflorescence composed usually entirely of hermaphrodite flowers but some species with sterile flowers proximally, fertile flowers distally, and often a few functionally staminate flowers in between. Flowers with sepals and petals valvate in bud; sterile flowers with a 5-lobed or entire calyx, fused ½-¾ its length, each lobe with a central raised nerve; petals 5, connate, each petal 1-3 nerved, staminodia 10, filamentous, white; functionally staminate flowers similar to fertile ones but either lacking an ovary or having only a rudimentary one; bisexual flowers similar to sterile ones but larger, with a 5-lobed calyx and 5 connate petals (free in one species), usually linear or lanceolate, 1-3 nerved; stamens 8-10, filaments exserted at anthesis, anthers either with a terminal apiculum or lacking an apical gland; pollen of 8- or 16-grained calymmate or acalymmate polyads, grains shed as tetrads if acalymmate, exine verrucate or psilate; ovary ovate, sessile, densely pilose or pubescent, style exserted (rarely included) at anthesis, stigma porate to broad funnelform. Fruits sessile, terete when immature, dorsiventrally compressed at maturity, either inertly dehiscent or more often elastically dehiscent from the apex, the valves recurved but not coiling after dehiscence (Fig. 146Q View Figure 146 ), pericarp woody in elastically dehiscent species, coriaceous in inertly dehiscent ones, sutural ribs often greatly thickened, interior of pod usually invaginated between seeds. Seeds obliquely or laterally positioned in the fruit, ovate to rhomboidal, pleurogram either U-shaped or forming nearly a complete oval.
Chromosome number.
Unknown.
Included species and geographic distribution.
Eleven species, in southern, western, and far northern Madagascar (Fig. 160 View Figure 160 ).
Ecology.
Restricted to seasonal xerophytic deciduous woodlands and scrub, especially in the spiny forests of south-western Madagascar, deciduous in long dry season.
Etymology.
From alantsili -, the Madagascan name for dry forest, and - dendron (Greek = tree) in reference to the distribution of the genus restricted to dry forest.
Human uses.
Unknown.
Notes.
Alantsilodendron is closely related to Dichrostachys and Gagnebina (Fig. 143 View Figure 143 ) but differs in having fused petals, and typically a capitate inflorescence lacking staminodial flowers. The current non-monophyly of Alantsilodendron (Fig. 143 View Figure 143 ) will be dealt with in a forthcoming monograph (see Dichrostachys and Dichrostachys clade notes for more details).
Taxonomic references.
Villiers (1994, 2002), both including illustrations.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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