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Electronic Flora of South Australia
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Electronic Flora of South Australia species Fact Sheet

Family: Fabaceae
Swainsona microphylla

Citation: A. Gray, U.S. Expl. Exped. 15:410 (1854).

Synonymy: Swainsona microphylla

Common name: Small-leaved swainson-pea.

Perennial decumbent or ascending herbs or undershrubs; indumentum sparse to dense, of basifixed or laterally attached hairs; stems few to several, 10-40 cm long; leaves 2-12 cm long, with 9-40 or more leaflets; leaflets oblong or obovate, obcordate or obtuse or retuse, 2-15 mm long, decreasing in size distally; stipules lanceolate to narrow-triangular, 1-10 mm long, with few hairs.

Flowers 6-10 mm long, on pubescent pedicels 1-2.5 mm long, in 10-30-flowered racemes usually on the distal half of the 10-30 cm long peduncle; bract triangular to lanceolate, 0.5-3 mm long, shorter or longer than the pedicel, scarious, rarely greenish, with more or less diffuse hairs; bracteoles minute, filiform, often caducous; calyx 2-4 (to 6 in subsp. affinis) mm long, glabrous or pubescent usually with dark hairs; teeth triangular, shorter than the tube; petals blue to purple (yellow in subsp. pallescens); standard broad-ovate, shallowly notched, broader than long, ecallose, (in subsp. affinis vertical folds sometimes present), with 2 yellowish-green blotches centrally, on a claw 1.5-2.5 mm long; wings shortest, oblong, auriculate above the long claw; keel about as long as the standard, semicircular, obtuse to subacute, slightly auriculate above the 2-3 mm long claw; ovary shortly stipitate, fusiform, glabrous, to 8-ovulate, attenuate into the style; style gradually tapering towards the tip, sometimes slightly flattened laterally, sparsely bearded all the way, with hair-tufts or a ring of hairs around the tip; tip truncate or attenuate into the straight or slightly geniculate stigma.

Pod subglobular, 6-10 x 4-6 mm, inflated, reticulate, glabrous, the suture not or rarely impressed, the style base persisting as a short beak, to 8-seeded; seed cordate, c. 1.5 x c. 1 mm, olive-green to brown, smooth.

Distribution:  All subspecies occur in S. Aust. except the typical one which is endemic to N.S.W.

S.Aust.: NW, LE, NU, GT, EP, MU.

Conservation status: native

Flowering time: No flowering time is available

SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia

Biology: No text

Key to Infraspecific taxa:
1. Pubescence of stems and leaves of dense spreading hairs
subsp. tomentosa 15e.
1. Pubescence of stem and leaves of sparse or dense appressed hairs
2. Style tip truncate, encircled by a ring of hairs; leaves with more than 30 small leaflets 1.5-4 x 1.3 mm; pubescence on stem and leaves dense
subsp. minima 15c.
2. Style tip attenuated (tapering, the terminal part straight or more or less geniculate), with short hairs or a hairtuft along the back; pubescence on stems and leaves sparse to dense; leaves with 9-43 leaflets
3. Pubescence of stems and leaves very sparse; leaves with 21-43 small obcordate-rotund or oblong thick leaflets 1-5 mm long (usually 2-3 x 1-3 mm) . subsp. glabrescens 15b
3. Pubescence of stems and leaves rather dense, with longer and loosely appressed hairs; leaves with 9-21 (usually 11-15) oblong or narrow-oblong leaflets 4-13 mm long (commonly 6-9 x 3-5)
4. Flowers blue (standard sometimes with 2 longitudinal folds)
subsp. affinis 15a.
4. Flowers yellow
subsp. pallescens 15d.

Author: Not yet available

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