Kew Bulletin

, Volume 63, Issue 1, pp 151–154

A new species of Macroptilium (Benth.) Urb. (Leguminosae: Papilionoideae: Phaseolinae) from North-Eastern Brazil

Article

DOI: 10.1007/s12225-007-9010-x

Cite this article as:
Delgado-Salinas, A. & Lewis, G.P. Kew Bull (2008) 63: 151. doi:10.1007/s12225-007-9010-x

Summary

A new species of Macroptilium sect. Microcochle (Benth.) J. A. Lackey is herein described from the states of Piauí and Bahia, Brazil. Macroptilium cochleatum is characterized by few-flowered inflorescences, calyx teeth longer than the tube, a tightly four-coiled keel, and linear, patent fruits. The discovery of this unique Macroptilium species, with its distally coiled keel, expands the diagnostic features of the genus. A key to the Brazilian species of sect. Microcochle is provided.

Keywords

Brazil Leguminosae Macroptilium New World Phaseolinae 

Introduction

The genus Macroptilium (Benth.) Urb. comprises nearly 20 species and is one of nine known genera in the New World Phaseolinae (Schrire 2005). Macroptilium is characterised by having long wing petals, longer than the standard and keel. At anthesis, the upwardly directed left wing takes the place of the standard. The diagnostic keel of Macroptilium has the distal portion hooked and rotated to the right (from the perspective of the flower). The genus is distributed from the south-western United States to northern Argentina and southern Uruguay. Species of the genus were divided into three different sections by Lackey (1983). According to Lackey (op cit.) and Fevereiro (1986), plants referable to sect. Microcochle are characterised by small flowers, c. 1 cm long, upper calyx lobes widely spreading, ovaries with few ovules (up to seven), and subspherical seeds. In Brazil, sect. Microcochle is represented by four species that grow mostly in the lowlands, in open habitats of caatinga, campo, cerrado, and restinga vegetation, sometimes on dunes and often on sandy soils and occasionally in seasonally inundated grasslands (Fevereiro op. cit.). The newly described species best fits the diagnosis of sect. Microcochle, although it displays unique characteristics within the group.

During routine identification of incoming material in the Kew herbarium a previously undescribed species of Macroptilium from Brazil was discovered. The new species proved to be strikingly distinct from all known species of sect. Microcochle, to which it is referred (Lackey 1983; Fevereiro 1986; Lewis 1987), and also to all other Macroptilium species. A description of the new species follows.Macroptilium cochleatumA. Delgado & G. P. Lewis, sp. nov. in sectione Microcochle (Benth.) J. A. Lackey ponenda, ad omnibus speciebus adhuc descriptis rostro carinae quadritorto facile distinguenda. Herba prostrate, caule volubili basi ramoso. Folia trifololiata, foliolis lineari-oblongis. Pedunculus folio brevior, 2 – 4- florus, floribus parvis. Calyx campanulatus vel subtubulosus, laciniis subulatis subaequalibus, tubo longioribus, 2 superioribus patentibus. Carina non hamata, rostro quadritorto. Legumen lineare demum subteres, patenter pilosissimum. Seminibus parvis rugosi tuberculatis instructum. Typus: Brazil, Bahia. Mun. Jussiape, 11 km de Jussiape na estrada para Morro Branco o Brejo de Cima, 7 Feb. 1997, A. M. Giulietti, R. Harley & S. Atkins PCD 5460 (holotypus HUEFS; isotypus K!).Prostrate trailing and climbing herbaceous vine. Stems slender, rooting at the lower nodes, sparsely pilose with white hairs c. 1.5 mm long, and shorter, retrorsely appressed hairs. Leaves trifoliolate, stipules ovate-lanceolate, 2 – 3 mm long, c. 1 mm wide, striate, four-nerved, not reflexed, persistent; stipels narrowly linear, acute, c. 1 mm long, as long as petiolules, not spreading; petioles mostly 5 cm long, canaliculate, sparsely pilose, with hairs c. 1 mm long, and shorter antrorsely appressed hairs also present, rachis considerably shorter, 3 – 5 mm long, canaliculate, mostly with short antrorsely appressed hairs; leaflets narrowly ovate to linear, acute at base and apex, apiculate, margins slightly revolute, softly pilose, with white antrorse hairs on both surfaces, secondary venation brochidodromus; leaflets of major leaves 7 – 10 times as long as wide, 3.5 – 5 cm long, c. 5 mm wide. Inflorescences short axillary pseudoracemes, with small peduncular bracts, ascending from prostrate stems or on a climbing, flexuose stem sometimes bearing cleistogamous flowers, peduncles 2.5 – 3 cm long, almost entirely covered with a mixture of long and short retrorse hairs, antrorsely directed near flower node, rachis 2 – 9 mm long with (1–) 2 slightly swollen flowering nodes, pilose; flowers 2 at each node; bracts subulate, caducous at bud stage; pedicels short, c. 1 mm long in fruit; bracteoles subulate, pilose and with minute glandular hairs, caducous. Flowers described as reddish-wine coloured, darkening to purplish as they dry out, the standard slightly paler or greenish; calyx tubular to subcampanulate, softly pilose, tube shorter than teeth, c. 1 mm long; teeth triangular-subulate, subequal, c. 2 mm long, the adaxial pair with slightly broader bases, distinctly spreading; corollas c. 8 mm long, standard orbicular, c. 5 mm in diameter, with two narrow auricles at the base, claw c. 1 mm long; wings with an obovate lamina, c. 7 mm long, claw adnate to staminal tube, c. 3 mm long, basal portion of lamina auriculate, strongly fused to pocket of the keel; keel petals fused into a beak, claws c. 2.5 mm long, fused to staminal tube, a prominent transverse pocket above claw, beak curved and tightly four-coiled, coils rotating inwards towards the main body of the keel; androecium diadelphous, coiled as keel, with nine stamens united into a staminal sheath, and one free vexillary stamen, base of vexillary stamen prominently expanded; anthers sub-basifixed to the filaments; gynoecium with an ovary c. 3 mm long, densely pilose, with a nectary disk at base, c. 1 mm long, ovules 7, style filiform, thickened at apex and coiled as keel, a short pollen brush below stigma, final coil of style hook-shaped, stigma globose, laterally placed at apex. Fruit linear, slightly falcate, subcompressed laterally, valves not constricted between the seeds, sparsely pilose, c. 2.5 cm long, 2.5 mm wide, beak short and curved, patent, at right angles to the axis, elastically dehiscent, c. 6-seeded. Seeds oblong-quadrate, 1.5 mm long, 2 mm wide, surface rugose-tuberculate, testa bicoloured, beige with light to dark brown mottling, hilum oval, excentric in position, rim aril tongue minute, lens discernible, confluent with hilum, same colour as testa, divided into two equal halves (Fig. 1).
Fig. 1

Macroptilium cochleatum. A habit, older stems, showing inflorescences with flower buds, flowers at anthesis, and immature fruits; B plant showing cleistogamic inflorescences on basal flexuose stems; C stem transverse section showing intermixed short and long pilose hairs; D leaflet section showing abaxial surface; E swollen floral node with flower (side view) showing subulate bracteoles at calyx base; F calyx opened out to show outer surface and sub-equal teeth; G standard petal inner face with two auricles at base above claw; H wing petal; J keel petals, distally bulged due to a 4-coiled apex; K keel, distally 4-coiled; L keel detail, showing stigma protruding; M keel with distal coiled portion unfolded, c. 8 mm long; N as for M showing an anther’s position within the keel; P staminal tube, distal portion not shown; Q vexillary stamen showing prominently expanded base, distal portion not shown; R anthers, sub-basifixed to the filaments; S gynoecium with ovary and nectary disk at base, distal portion of style not shown; T style distal portion with pollen brush and stigma; U fruit held patent on infrutescence; V seed showing rugose-tuberculate surface. A, CE and U, V from A. M. Giulietti, R. Harley &S. Atkins PCD 5460, B and FT from Gardner 2537. Scalebars: A, B 1 cm; ES, U and V 1 mm; T 0.5 mm. Drawn by Pat Halliday.

DISTRIBUTION

Brazil: Bahia and Piauí.

Brazil

Bahia, Mun. Jussiape, 11 km de Jussiape na estrada para Morro Branco e Brejo de Cima, 7 Feb. 1997, A. M. Giulietti, R. Harley & S. Atkins PCD 5460 (holotype HUEFS; isotype K!). Piauí, Near Oeiras, July 1839, Gardner 2537 (K!).

Habitat

In open caatinga woodlands, on damp sandy soils (Giulietti et al. 5460) and in marshland (fide Gardner 2537).

Conservation Status

Macroptilium cochleatum is apparently a rare species since, as far as we know, it took approximately 150 years before it was collected for a second time. The conservation status is DD (data deficient).

Etymology

The specific epithet cochleatum refers to the tightly coiled beak of the keel which resembles a snail shell.

Notes

On the basis of the two specimens available for study, this is evidently a distinctive species of the genus Macroptilium. Its coiled keel separates it from all previously described species in this genus. Vegetative specimens of Macroptilium cochleatum are most likely to be confused with forms of M. gracile (Poepp. ex Benth.) Urb. (sect. Macroptilium) which has similar linear leaflets and with which M. cochleatum may co-occur. Macroptilium gracile differs in having inflorescences up to 30 cm long, flowers 1.5 – 2 cm long, fruits 6 – 7.5 cm long, and seeds larger than 3 mm in diameter. In addition, the diagnostically coiled keel in M. cochleatum clearly distinguishes it from M. gracile. Unique in Macroptilium by its strikingly coiled keel, M. cochleatum can, nevertheless, be placed in section Microcochle due to its calyx teeth widely spreading, its small flowers, less than 1 cm long, and by its ovule number. A key to the species of section Microchocle found in Brazil is presented above.

Key to the Species of Macroptilium Sect. Microcochle in Brazil

  • 1. Calyx teeth shorter than or equal to the tube, 0.6 – 1 mm long..................................................................................2

  • 1. Calyx teeth longer than the tube, 2–6 mm long...........................................................................................................3

  • 2. Leaflets coriaceous, linear-lanceolate to oblong-elliptic; flowers yellow, 1–1.5 cm long; fruits falcate, 3–4 mm wide, deflexed. Central western, south-eastern and southern Brazil; Argentina, Bolivia and Paraguay..................................................................................................................................M. prostratum (Benth.) Urb.

  • 2. Leaflets chartaceous, ovate with basal lobes; flowers red-salmon to orange, c.1.3 cm long; fruits falcate, 2–3 mm wide, deflexed. North-eastern and south-eastern Brazil................M. sabaraense (Hoehne) V. P. Barbosa

  • 3. Leaflets linear; inflorescences less than 10 cm long; keel petals tightly four-coiled at apex; fruits linear-subfalcate, c.2 mm wide, patent. North-eastern Brazil....................................................M. cochleatum A. Delgado & G. P. Lewis

  • 3. Leaflets ovate to orbicular, subrhombic; inflorescences more than 10 cm long; keel petals hooked at apex; fruits falcate, 3–4 mm wide, deflexed.........................................................................................................................................4

  • 4. Leaflets mostly orbicular; inflorescences up to 30 cm long; flowering nodes 12–35; calyx teeth 7–8 mm long. North-eastern Brazil; Paraguay..........................................................................M. martii (Benth.) Maréchal & Baudet

  • 4. Leaflets ovate to subrhombic; inflorescences up to 20 cm long; flowering nodes 6–8; calyx teeth 3–3.5 mm long. Southern Brazil; Argentina, Paraguay and Uruguay........M. psammodes (Lindem.) S. I. Drewes and R. A. Palacios

Acknowledgments

We are grateful to Pat Halliday for the excellent line drawing; and to Bernard Verdcourt for providing the Latin diagnosis. Also thanks to Ruth Clark for technical help and to R. K. Brummitt for assistance on nomenclatural matters. Funding for the first author’s research has been provided by UNAM-DGAPA and by the KLARF-Programme, Royal Botanic Gardens, Kew.

Copyright information

© The Board of Trustees of the Royal Botanic Gardens, Kew 2008

Authors and Affiliations

  1. 1.Departamento de Botánica, Instituto de BiologíaUniversidad Nacional Autónoma de MéxicoMéxicoMexico
  2. 2.Herbarium, Royal Botanic Gardens, KewRichmondUK

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