Crotalaria namuliensis Polhill & T.Harris

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/108613974/108620119

Conservation

LC - least concern

Harris, T., Darbyshire, I. & Polhill, R. Kew Bull (2011) 66: 241. https://doi.org/10.1007/s12225-011-9277-9

Morphology General Habit

Erect, well to sparsely branched annual or short-lived perennial, branching from a single stem, 10 – 50 cm tall Legume sessile, obliquely inserted, shortly cylindrical, 6 – 7 × 3.5 – 4.5 mm, adpressed pubescent

Morphology Stem

Stems adpressed pubescent, branches with very dense short stiff hairs c. 0.3 mm long

Morphology Leaves Stipules

Stipules absent

Morphology Leaves

Leaves 3-foliolate; leaflets oblanceolate, 3 – 10 × 1.5 – 4 mm, apex truncate with an acumen, very sparsely fine pubescent above, densely adpressed pubescent beneath with short stiff hairs; petiole 2 – 5.5 mm long

Morphology Reproductive morphology Inflorescences

Racemes dense, terminal, 10 – 17 mm long, 3 – 10-flowered without many flowers developing in the axils below; bracts linear, 1 – 2 mm long, abaxially densely pubescent; pedicels 3 – 4.5 mm long, ascending; bracteoles on pedicel, filiform, c. 1 mm long, abaxially densely pubescent

Morphology Reproductive morphology Flowers Calyx

Calyx 3.5 – 4.5 mm long, adpressed pubescent; upper lobes attenuately triangular, 2 – 2.5 times as long as the tube

Morphology Reproductive morphology Flowers Corolla

Corolla: standard elliptic, 6 – 7.5 × 5.5 – 6.5 mm, inner face yellow occasionally marked with a red crescent, outer face red, pubescent on upper part of midvein and densely so near apex, base rounded with claw 0.3 – 1 mm long; wings nearly oblong, slightly broadened upwards, c. 2 mm wide, 4.5 – 7 mm long, base asymmetrical with claw 1 – 1.3 mm long; keel angular and slightly twisted at apex, 7 – 9 mm long, base asymmetrically rounded with claw 0.5 – 1 mm long

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens: filaments bearing longer anthers fused for 2 – 2.5 mm, free parts 4 – 4.5 mm long, filaments bearing shorter anthers fused for 1.25 – 1.5 mm, free parts 0.9 – 1.7 mm long

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary c. 2.5 mm long, pubescent outside, glabrous inside, c. 10-ovulate, style geniculate, the distal part c. 4.5 mm long, hairy along both sides

Morphology Reproductive morphology Seeds

Seeds ± 10 per legume, c. 1.5 mm long, without an aril.

Ecology

Only known from these four collections all from montane grassland above 1800 m on Mt Namuli. Potentially on comparable mountains in northern Mozambique.

Conservation

This species is preliminarily assessed as Critically Endangered (CR B1b(iii) + B2ab(iii)) as it is currently only known from one location and the current known Extent of Occurrence is 1.25 km2. There is a potential threat to the extent of grassland habitat as a result of expansion of cattle grazing on the Muretha plateau, Mt Namuli. This assessment may need to be downgraded if collections are made from new localities.

Note

Crotalaria namuliensis is easily recognised as a member of sect. Dispermae Wight & Arn. on account of the keel with a twisted beak, the small pods and lack of stipules. C. namuliensis is distinguished from C. argyrolobioides Baker by its smaller flowers (keel 7 – 9 mm vs 9 – 12 mm) and smaller pods (width 3.5 – 4.5 vs 5 – 5.5 mm), and by its more compact inflorescences. When material of this entity was first examined in the Herbarium at Kew, it was almost immediately evident that it represented an interesting new species. It is certainly closely related to C. argyrolobioides, which is quite widely distributed on high ground along the Western Rift from the Marungu Mts to Mt Mulanje. The several specimens from the montane grassland of Namuli represent a uniform facies that is quite distinct from other species in the cluster around C. argyrolobioides. As explained in the account of that species in Polhill (1982: 312 – 313), C. argyrolobioides is rather variable, so that its close and more uniform allies are a little difficult to distinguish precisely. C. argyrolobioides extends down from high ground along rivers into areas of Brachystegia woodland and diversifies considerably. When we came to write up C. namuliensis for this paper it was a little disappointing that the technical characters we offer to define the entity are not quite as convincing as might be desired. However there is no clinal variation or signs of intergradation between the highland populations of C. argyrolobioides on Mulanje and C. namuliensis on Mt Namuli that would suggest ranking at subspecific level or less.