Author: Linnaeus
Morfological description
Trees or shrubs (sometimes semiscandent), unarmed or with intrastipular spines (rarely shrubs with tendrils or thorns) or lianas with (rarely without) simple tendrils (Bauhinia vahlii tendril 139583 ); branches terete or angular. Stipules various, deciduous or persistent; intrastipular trichomes variously developed, sometimes adpetiolarly enlarged and forming a spine.
Leaves entire (Bauhinia burbidgei lv FM10 ), 2-lobate (Bauhinia excelsa lf+bud FM6 ), or 2-foliolate, midrib with weakly to strongly developed secondary veins.
Flowers solitary or few to many in terminal or subterminal and axillary racemes, corymbs, or panicles (rarely cauliflorous), bisexual or rarely unisexual (polygamous or dioecious) (Bauhinia galpinii fl/lf 428805 ; Bauh kockiana overv 431667 ). Hypanthium short cupulate, campanulate, turbinate, or infundibuliform to long tubular. Calyx open or closed at apex, at anthesis spathaceous or irregularly divided to mouth of hypanthium into 2-5 lobes or 5-lobed or -dentate in upper part only. Petals (1-)5(-6), white, various shades of red to purple, or yellow, subequal to greatly unequal. Fertile stamens 0-10; filaments connate (monadelphous or diadelphous) or free, strongly to weakly declinate; anthers globose, ellipsoid to linear, opening by a longitudinal slit or a central pore in each theca. Reduced stamens or staminodes often present. Ovary 1- to many-ovuled; gynophore adnate with abaxial wall of hypanthium or free; style elongate or obsolete; stigma peltate, capitate or little differentiated from style.
Fruits flat, suborbicular to broadly elliptic or obovate to linear, woody or thin-valved, dehiscent (often explosively) or indehiscent, continuous, filled, or septate within.
Seeds orbicular to elliptical, endosperm present or absent.
Distribution
About 300 species all over the tropics. In Malesia 68 species.
Habitat
Found in most types of vegetation, evergreen forest, dry deciduous forests and mountain forests, in Africa in savannas and semideserts. In China to over 3000 m altitude, where stunted forms occur in grazing land.
Fossils
Records are few and some are uncertain. Newberry [Bull. Torrey Bot. Club 13 (1885) 77] described Bauhinia cretacea from Cretaceous clay deposits in New Jersey, USA. The illustration is not absolutely convincing. Berry [Proc. U. S. Nat. Mus. 54 (1917) 115, 144] described another species B. potosiana from Tertiary deposits in Bolivia, a plant with bifoliolate leaves; in our opinion it is very questionable if this belongs to the present genus. Kryshtoforich [Amer. J. Sci. 46 (1918) 507] refers to B. cretacea from a Miocene flora from Sakhalin. Later references to Bauhinia in fossil floras have not been found.
Anatomy
The stem anatomy has been studied in several species and particular attention has been paid to the anomalous growth of several of the large lianas, some producing band-shaped, winged and undulated stems ('monkey-ladders', 'escada das macacos': Bauhinia monkey-ladder 256029 ), due to the cambium being confined to two opposed areas, e. g. B. scandens . In B. vahlii successive rings of growths are found and in, e. g., B. championi a cleft xylem mass is found and one or two successive rings of xylem and phloem; secondary bundles arise in the pith.
Palynology (acuminata Bauhinia poll 386307 ,aherniana Bauh pol 386338 )
Pollen in monads (rarely in tetrads), (small), medium to large, inaperturate, 3-7-colpate, 3-7-porate, 3-7-colporate, 3-pororate or 3-7-colporoidate, prolate to spheroidal to oblate, sexine various. More than 80% of the species have been studied.
Literature
I.K. Ferguson, J. Palynol. 26 (1990) 73-82.
I.K. Ferguson & K.J. Pearce, Linn. Soc. Symp. Ser. 12 (1986) 283.
I.K. Ferguson & H. Banks, Rev. Palaeobot. Palynol. 83 (1994) 31.
S.S. Larsen, Grana 14 (1975) 114.
Chromosomes
2n = 24, 26, 28, 42, 56. About 40 species have been studied.
Taxonomy
As this large genus comprises a wide range of life-forms from shrubs to trees and lianas and an unusual variation in flower structure some authors as, e. g., latest de Wit (1956) have found it evident to split it into several distinct genera. The present authors have studied the genus from all over its distribution area and found a reticulate pattern of variation. They have drawn the conclusion, now generally accepted among Legume-specialists, that Bauhinia in the sense of Linnaeus, Bentham, De Candolle, Taubert, and Hutchinson is an evolutionary unit and a very natural genus.
In the above only generic synonyms related to species occurring in the Malesian area have been mentioned. No less than 26 segregated genera have been created, see Wunderlin, (1976) and Wunderlin, Larsen & Larsen (1987).
Pollination
Little has been done to study the genus in nature. From Java (?) come reports on bat-pollination, which is also observed in S. America. In several S. American species bird-pollination has been observed, while the many medium- and small-flowered species with nectariferous discs probably are entomophilous.
KEY TO THE SUBGENERA
1a. Trees or shrubs (rarely semiscandent), sometimes with intrastipular spines, never with tendrils ......................................................................................................................... 7
1b. Lianas with tendrils, never with intra-stipular spines or thorns
Subgenus Phanera ................................ 2
2a. Leaves bifoliolate on flowering shoots; fertile stamens 10
SectionLysiphyllum
with the following species: Bauhinia binata, Bauhinia dewitii, andBauhinia diptera
2b. Leaves entire or bilobed on flowering shoots; fertile stamens 3, rarely 2 .......... 3
3a. Anthers opening by a central pore
Section Palmatifolia
with the following species: Bauhinia bidentata, Bauhinia burbidgei, Bauhinia campanulata, Bauhinia cuprea, Bauhinia decumbens, Bauhinai elmeri, Bauhinia finslaysoniana, Bauhinia foraminifer, Bauhinia franckii, Bauhinia havilandii, Bauhinia kingii, Bauhinia kockiana, Bauhinia lambiana, Bauhinia lucida, Bauhinia menispermacea, Bauhinia posthumi, Bauhinia pyrrhoneura, and Bauhinia wrayi
3b. Anthers opening by a slit lengthwise .......................................................................... 4
4a. Nectariferous disc present Section Lasiobema
Bauhinia curtisii, Bauhinia flava and Bauhinia scandens;
4b. Nectariferous disc absent ................................................................................................ 5
5a. Flowers pseudopapilionaceous; fleshy, digitate body present on the rim of the hypanthium Section Austrocercis
with the following species: Bauhinia williamsii
5b. Flowers not pseudopapilionaceous; fleshy, digitate body absent............................ 6
6a. Calyx open at apex before anthesis, remaining campanulate
SectionTubicalyx
with the following species: Bauhinia strychnoidea, and Bauhinia tubicalyx
6b. Calyx closed before anthesis, splitting into 2-5 lobes
Section Phanera
with the following species: Bauhinia aherniana, Bauhinia andersonii, Bauhinia audax, Bauhinia bassacensis, Bauhinia corymbosa, Bauhinia crudiantha, Bauhinia endertii, Bauhinia excelsa, Bauhinia excurrens, Bauhinia fabrilis, Bauhinia ferruginea, Bauhinia fulva, Bauhinia glabrifolia, Bauhinia glabristipes, Bauhinia glauca, Bauhinia gracillima, Bauhinia hendersonii, Bauhinia integrifolia, Bauhinia kostermansii, Bauhinia lingua, Bauhinia merrilliana, Bauhinia pachyphylla, Bauhinia pauciflora, Bauhinia praesignis, Bauhinia rahmatii, Bauhinia ridley, Bauhinia semibifida, Bauhinia steenisii, Bauhinia stipularis, and Bauhinia sylvani;
7a. Calyx spathaceous or dividing to mouth of hypanthium into 2-5 lobes
Subgenus Bauhinia
with the following species: Bauhinia acuminata, Bauhinia ampla, Bauhinia dolichocalyx, Bauhinia galpinii, Bauhinia hirsuta, Bauhinia monandra, Bauhinia pottsii, Bauhinia purpurea, Bauhinia tomentosa, Bauhinia variegata, and Bauhinia viridens.
7b. Calyx closed and irregularly splitting at anthesis
Subgenus Elayuna
with the following species: Bauhinia malabarica,
DUBIOUS SPECIES
Bauhinia cordifolia Roxb.,Fl. Ind., ed. Carey, 2 (1824) 332. - Type unknown.
This species described from the Moluccas and by Baker referred to Bauhinia emarginata Jack belongs undoubtedly to Bauhinia finlaysoniana after leaf shape and nerves, and the locality. It cannot be placed in one of the varieties.
Bauhinia emarginata Jack, Mal. Misc. 2 (1822) 75, nom. illeg., non Miller.
De Wit, Reinwardtia 3 (1956) 499, placed this name as a synonym under Bauhinia bidentata , mentioning that it had not been possible to trace the type. In the protologue the leaves are described as "cordate, subrotund-oval terminating in a short, blunt, emarginate acumen, very entire". This suggests in our opinion Bauhinia pyrrhoneura which also matches the geographic location Sumatra.
Bauhinia parvifolia Teijsm. & Binnend., Nat. Tijdschr. Ned. Ind. 29 (1867) 257.
According to de Wit, l. c., this name is represented by sterile herbarium specimens in BO, in our opinion probably belonging to Bauhinia corymbosa.
Phanera dasycarpa Miq., Sumatra (1858) 1078.
See Note 1 under Bauhinia rahmatii Merr.
EXCLUDED SPECIES
Bauhinia inermis Perr., Mém. Soc. Linn., Paris 3 (1902) 1824, nom. nud., nom. illeg. non Forssk. nec Pers.; de Wit,Reinwardtia 3 (1956) 536.
Described as a species from the Philippine mountains.
Bauhinia latisiliqua Cav., Ic. 5 (1799) 5, pl. 407; de Wit, Reinwardtia 3 (1956) 536.
A name based on a collection consisting of leaves of a Bauhinia and a fruit of a Caesalpinia.
Bauhinia lunaria Cav., Ic. 5 (1799) 5, pl. 407; de Wit, Reinwardtia 3 (1956) 536.
A South American species belonging to the section Casparea.
Bauhinia retusa Roxb., Fl. Ind. 2 (1832) 322. - Lasiobema retusa (Roxb.) de Wit, Reinwardtia 3 (1956), 538.
An Indian species erroneously ascribed to Luzon by Fernandez-Villar, Nov. App. (1880) 72.
Bauhinia rufa (Grah. ex Benth.) Baker in Hook. f., Fl. Brit. India 2 (1878) 280, non Steud. - Phanera rufa Benth. in Miq., Pl. Jungh. (1852) 263.
An Indian species erroneously ascribed to the Philippines by Fernandez-Villar, Nov. App. (1880) 72. The correct name of this species is B. ornata Kurz.
Bauhinia subrotundifolia Cav., Ic. 5 (1799) 4, pl. 406; Naves in Blanco, Fl. Filip., ed. 3 ( 1877) pl. 82; Fern.-Vill., Nov. App. (1880) 72; Vidal, Rev. Pl. Vasc. Filip. (1886) 117.
A South American species belonging to the section Casparea , erroneously ascribed to the Philippines by various authors.
Bauhinia cucullata Desv., J. Bot., ed. Desv. 3 (1814) 74; Zoll., Nat. Geneesk. Arch. Neerl. Ind. 3 (1846) 69.
A South American species not occurring in the Malesian area; see de Wit, Reinwardtia 3 (1956) 535.