Stylosanthes Sw.

First published in Prodr. Veg. Ind. Occ.: 108 (1788)
This genus is accepted
The native range of this genus is Central & E. U.S.A. to Tropical America, Africa to Arabian Peninsula, India, Sri Lanka.

Descriptions

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Note

The present circumscription of Dalbergieae sens. lat. contains radical changes to Dalbergieae sensu Polhill (1981d: 233–242). In the first instance it takes a traditional view of the tribe by including genera such as Vatairea and Vataireopsis (now in the Vataireoid clade, see Figs. 1& 40) and Andira and Hymenolobium, which in Wojciechowski et al. (2004) are sister to the combined Dalbergioid clade of Lavin et al. (2001a), plus Amorpheae. The bulk of the treatment, however, recognises the cryptic Dalbergioid clade (Lavin et al., 2001a) as comprising tribe Dalbergieae sens. lat., diagnosed by the synapomorphy of aeschynomenoid root nodules. This clade includes all the genera placed in the Dalbergieae sensu Polhill (1981d: 233– 242), the Aeschynomeneae sensu Rudd (1981) and the Adesmieae sensu Polhill (1981g: 355–356), plus subtribe Bryinae of the Desmodieae sensu Ohashi et al. (1981) as well as the genus Diphysa (tribe Robinieae sensu Polhill & Sousa (1981)).The placements of all members of the Dalbergioid clade within the classification presented here and in those of Polhill (1981d: 233–242; 1981g: 355–356), Polhill & Sousa (1981), Ohashi et al. (1981) and Rudd (1981) are listed in Fig. 40.

Dalbergieae sensu Polhill (1981d) contained 19 genera defined by woody habit, supposedly plesiomorphic flowers, pods with a specialised seed chamber and seeds that accumulated alkaloids. Polhill (1981d) noted that there seemed to be two centres within the Dalbergieae: one around Andira with Hymenolobium, Vatairea, Vataireopsis, Dalbergia, and Machaerium, and one around Pterocarpus. He also highlighted evidence from wood anatomy (Baretta-Kuipers, 1981) which showed that Andira, Hymenolobium, Vatairea, and Vataireopsis have coarser wood structures more typical of members of the Sophoreae than the remaining members of the Dalbergieae. The study of fruit and seedling morphology by Lima (1990) further supported these two centres within the Dalbergieae: one including Andira, Hymenolobium, Vatairea, and Vataireopsis, and the second the remaining genera. Most recently several molecular and morphological studies (e.g., Lavin et al., 2001a; Pennington et al., 2001; Wojciechowski et al., 2004) confirm that these four genera do not belong in the Dalbergioid clade. Since there is, however, still much work to be done to resolve the phylogenetic relationships of these four genera, they have been kept in tribe Dalbergieae sens. lat. in this treatment to avoid tentative placements, which might be treated by users as formal.

The tribe Aeschynomeneae sensu Rudd (1981) contained 25 genera characterised by lomentaceous pods, although some members lack loments (e.g., Arachis, Ormocarpopsis, Diphysa spp., Ormocarpum spp., and Pictetia spp.). None of the Aeschynomeneae had previously been considered closely related to the Dalbergieae, but the work of Lavin et al. (2001a) has resolved all the ‘aeschynomenoid genera’ within the Dalbergioid clade.

The taxonomic history of the monogeneric tribe Adesmieae sensu Polhill (1981g) is very different from that of the Dalbergieae. The Adesmieae combines the presumed plesiomorphic trait of free stamen filaments, with presence of lomentaceous pods that are supposedly derived. This combination of features suggested a taxonomically isolated position far removed from the Dalbergieae. The analyses of Lavin et al. (2001a) based on molecular sequence and morphological data, however, support Adesmia (nested together with five genera of Rudd’s Aeschynomeneae) being sister to the Pterocarpus and Dalbergia clades. The neotropical genera Brya and Cranocarpus were placed together in a new subtribe Bryinae of Desmodieae in the classification of Ohashi et al. (1981). The features common to these genera are periporate pollen and glochidiate hairs or glandular trichomes. In the molecular studies of Doyle et al. (1995) and Bailey et al. (1997), Brya and Cranocarpus did not lack the intron for the chloroplast gene rpl2 nor for the open reading frame ORF184, which are characteristic of the other desmodioid genera studied. Bailey et al. (1997), therefore, suggested that Brya and Cranocarpus should be removed from the Desmodieae. Their findings were strongly corroborated by the three gene analyses of Lavin et al. (2001a) which place the two genera in the Pterocarpus clade (Fig. 40).

One further transfer has been made in the Dalbergioid clade since Rudd (1981) and Polhill & Sousa (1981). Lavin (1987) transferred Diphysa from the Robinieae to tribe Aeschynomeneae based on the absence of canavanine in the seeds, a feature consistently present in the Robinieae (Lavin, 1986). Lavin (1987) also listed 14 morphological characters that placed Diphysa with the Aeschynomeneae rather than the Robinieae. In the phylogenetic analyses of Lavin et al. (2001a), Diphysa is resolved in the Dalbergioid clade nested within the ‘transatlantic clade’ (Fig. 40), first identified by Lavin et al. (2000).

Finally, since 1981 four new genera have been published: the Brazilian monotypic Grazielodendron (Lima, 1983b), the possibly extinct Madagascan endemic Peltiera (Labat & Du Puy, 1997), Zygocarpum, the Horn of Africa – Arabian segregate of Ormocarpum (Thulin & Lavin, 2001) and Maraniona from northern Peru (Hughes et al., 2004). Three genera have also been placed in synonymy since 1981: the Caribbean genus Belairia which is a synonym of Pictetia (Beyra-Matos & Lavin, 1999), and the genera Pachecoa and Arthrocarpum which Thulin (1999) synonymised under Chapmannia. In this treatment 49 genera and (1319) –1325–(1331) species are recognised in Dalbergieae sens. lat. (including 4 basally branching dalbergioid genera comprising c. 58 species, and (1261)–1267– (1273) species in the 45 genera of the Dalbergioid clade [Lavin et al., 2001a]).The following informal groupings of genera are based on the work of Lavin et al. (2001a): Adesmia clade: 6 genera; c. 360 species; neotropical except Zornia, which is pantropical. Pterocarpus clade: 22 genera; c. 200 species centred in the Neotropics, Pterocarpus and Stylosanthes are pantropical, Inocarpus Asian, and Chapmannia transatlantic.Dalbergia clade: 17 genera; c. 706 species which are pantropical, but centred in Africa; Weberbauerella, Soemmeringia, Pictetia and Diphysa are neotropical, Machaerium transatlantic, Dalbergia and Aeschynomene are pantropical, and Geissaspis Asian. Isolated genera: 4 genera; 58 species, neotropical except Andira, which has one amphiatlantic species.

Mohlenbrock (1957) placed Stylosanthes in tribe Hedysareae subtribe Stylosanthinae, related to Zornia, Chapmannia and Arachis; Rudd (1981) placed it in tribe Aeschynomeneae, subtribe Stylosanthinae related to Arthrocarpum and Pachecoa (both synonyms of Chapmannia in this treatment), Chapmannia and Arachis; Lavin et al. (2001a), based on DNA sequences, placed Stylosanthes in the Pterocarpus clade, sister to Arachis, and nested with Chapmannia (Fig. 40)
Habit
Subshrubs or perennial herbs
Ecology
Seasonally dry tropical to warm temperate woodland, wooded grassland, thicket, shrubland and grassland, on sandy or rocky soils, along streams and sometimes weedy in old cultivated lands and on roadsides
Distribution
native to New and Old World, mainly neotropical (c. 23 spp.; centred in S America [13 spp.] with 4 spp. in N & C America and 6 spp. widespread in the Neotropics) and 2 spp. widespread in Africa, Madagascar, India and Sri Lanka ( S. fruticosa (Retz.) Alston [wild lucerne] and S. erecta P.Beauv). Several New World spp. have been cultivated and are naturalised in Africa, Asia and Australia (e.g., S. guianensis (Aubl.) Sw. sens. lat., S. humilis Kunth and S. viscosa Sw.)
[LOWO]

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit
Mostly low herbs, annual or perennial, or sometimes small shrubs, often with viscid pubescence; leaves pinnately 3-foliolate, stipules united to the base of the petiole, stipels absent.
Morphology Reproductive morphology Flowers
Flowers small, yellow, in chiefly terminal spikes or heads, each flower nearly sessile in the axil of a 2-dentate or divided bract, the pedicel very short and adnate to the bract, sometimes accompanied by a bristle-like sterile flower.
Morphology Reproductive morphology Flowers Calyx
Calyx with a long, stalk-like tube and with the 4 upper lobes joined, the lower one narrower and distinct
Morphology Reproductive morphology Flowers Corolla
Petals and stamens inserted at top of the calyx-tube; standard roundish; stamens 10, all united into a closed sheath, the anthers alternately long and short
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary subsessile; style hair-like; ovules 2 or 3
Morphology Reproductive morphology Fruits
Pods compressed, 1–2-jointed, the joints reticulate or muricate, the apical one with a hooked beak.
Distribution
A genus of about 30 species, chiefly in tropical America, a few in tropical Africa and Asia.
[Cayman]

Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

Morphology General Habit
Erect or spreading perennial herbs or subshrubs, often somewhat hispid with glandular hairs
Morphology Leaves
Leaves pinnately 3-foliolate or abnormally 1-foliolate; stipules adnate to the petiole for most of their length, persistent, biapiculate; stipels absent
Morphology Reproductive morphology Inflorescences
Inflorescences usually dense, axillary or terminal, composed of 1-flowered elements in spikes or panicles; primary bracts l(–2–3)-foliolate, imbricate, persistent; secondary bracts lanceolate or irregularly 2–3-fid, hyaline, persistent, ciliate
Morphology Reproductive morphology Flowers
Flowers subsessile, accompanied by 1–2 persistent linear hyaline ciliate bracteoles and sometimes by a plumose filiform axis representing a reduced part of an inflorescence now no longer present
Morphology Reproductive morphology Flowers Hypanthium
Receptacle (hypanthium) long and filiform
Morphology Reproductive morphology Flowers Calyx
Calyx 5-lobed; lobes joined at the base, membranous, the lowest longest and the upper pair joined for about half their length
Morphology Reproductive morphology Flowers Corolla
Standard rounded or obovate, emarginate, narrowed into a basal claw; wings oblong or obovate, free, with a lateral basal spur and a small internal appendage and also with a series of small pockets on the blade; keel-petals similarly spurred and appendaged Corolla usually small, yellow
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens all joined; 5 anthers longer and subbasifixed alternating with 5 shorter and versatile
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary linear, sessile, 2–3-ovuled; style long and filiform, after flowering breaking off towards the middle or nearer the base, the lower part persistent, recurved or revolute with the dilated apex simulating a stigma; true stigma terminal, minute
Morphology Reproductive morphology Fruits
Pods oblong, compressed, beaked, 1–2-jointed, but usually either the upper or lower joint aborted, reticulate or muriculate
Morphology Reproductive morphology Seeds
Seeds approximately ovoid or irregularly oblong, compressed; hilum often eccentric; aril somewhat developed or absent.
[FTEA]

Leguminosae, B. Verdcourt. Flora Zambesiaca 3:6. 2000

Morphology General Habit
Erect or spreading perennial herbs or subshrubs, often somewhat hispid with glandular hairs.
Morphology Leaves
Leaves pinnately 3-foliolate, or abnormally 1-foliolate; stipules adnate to the petiole for most of their length, persistent, biapiculate; stipels absent.
Morphology Reproductive morphology Inflorescences
Inflorescences usually dense, axillary or terminal, composed of l-flowered groups (reduced inflorescence parts) in spikes or panicles; primary bracts l(2–3)-foliolate, imbricate, persistent; secondary bracts lanceolate or irregularly 2–3-fid, hyaline, persistent, ciliate.
Morphology Reproductive morphology Flowers
Flowers subsessile, accompanied by 1–2 persistent linear hyaline ciliate bracteoles and sometimes by a plumose filiform axis representing a reduced part of an inflorescence now no longer present.
Morphology Reproductive morphology Flowers Receptacle
Receptacle (hypanthium) long and filiform.
Morphology Reproductive morphology Flowers Calyx
Calyx 5-lobed; lobes joined at the base, membranous, the lowest lobe longer than the rest, the upper pair joined for about half their length.
Morphology Reproductive morphology Flowers Corolla
Corolla usually small, yellow; standard rounded or obovate, emarginate, narrowed into a basal claw; wings oblong or obovate, free, with a lateral basal spur and a small internal appendage and also with a series of small pockets on the blade; keel petals similarly spurred and appendaged.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens all joined; 5 anthers longer and sub-basifixed alternating with 5 shorter and versatile.
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary linear, sessile, 2–3-ovuled; style long and filiform, breaking off towards the middle or nearer the base after flowering, the lower part persistent, recurved or revolute with the dilated apex simulating a stigma; true stigma terminal minute.
Morphology Reproductive morphology Fruits
Fruit oblong, compressed, beaked, 1–2-jointed, but usually either the upper or lower loment aborted, reticulate or muriculate.
Morphology Reproductive morphology Seeds
Seeds approximately ovoid or irregularly oblong, compressed; hilum often eccentric; aril somewhat developed or absent.
[FZ]

Uses

Use
Major livestock fodder plants in warm temperate and tropical areas of the world (e.g., S. guianensis or Brazilian lucerne ); several species are planted as soil stabilisers and improvers, and as ground cover, in e.g., coffee plantations; also used for medicine
[LOWO]

Sources

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of the Cayman Islands

    • Flora of the Cayman Islands
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Herbarium Catalogue Specimens

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Science Photographs

    • Copyright applied to individual images
  • Legumes of the World Online

    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • World Checklist of Vascular plants (WCVP)

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0