Mimosa, Linnaeus, 1753

Identification Key View in CoL

The following key distinguishes Mimosa longepedunculata from other treelet species with glandular indumentum and M. tocantina from other procumbent shrubby species belonging to M. ser. Pachycarpae and occurring at Chapada dos Veadeiros. It is largely based on the key for M. sect. Habbasia ser. Pachycarpae by Barneby (1991), also available at the New York Botanical Gardens’s Barneby Legume Catalogue (http://sweetgum.nybg.org/legumes/barneby/ mimosa_keys.php).

1. Procumbent shrubs; glandular setae absent ...................................................................................................................................... 2

- Treelets, usually at least 2 m tall; glandular setae present on branches ........................................................................................... 3

2. Rosette-shrubs with prostrate branches; stipules barbate with orange-red setae 6–12 mm long; pinnae pairs distant 2–4 mm from each other ................................................................................................................................. M. irwinii Barneby (1991: 422–423)

- Procumbent shrubs with assurgent synflorescences; stipules strigose with yellowish or ochraceous setae less than 6 mm long; pinnae pairs distant 10–20 mm from each other ........................................................................................................... M. tocantina

3. Stipules broadly ovate 15–30 × 7–13 mm ........................................................................................................................................ 4

- Stipules narrowly triangular or triangular 3.5–16 × 0.5–5.5 mm ..................................................................................................... 5

4. Filiform setae present on branches; peduncles 5–8 cm; glomerules without filaments ca. 20 mm diam.; corolla 7–8 mm ............... .............................................................................................................................................................................................. M. regina

- Filiform setae absent from branches; peduncles up to 4 cm; glomerules without filaments ca. 12 mm diam.; corolla 4.5–6 mm .... ..................................................................................................................................................................................... M. rhodostegia

5. Glomerules in a long double-raceme, exserted more than 10 cm from foliage ............................................................................... 6

- Glomerules among leaves (although not hidden by these), clearly not in an exserted double-raceme ............................................ 8

6. A spiculate projection present on rachillas, between pinnae pairs ............................................................................. M. dominarum

- Spiculate projection absent from rachillas ....................................................................................................................................... 7

7. Branches indumentum largely composed by filiform setae; stipules 4–5 mm long; peduncles 5–8 cm long ................ M. rheiptera

- Branches indumentum largely composed by simple trichomes; stipules 9–12 mm long; peduncles 4–5 cm long ............................. .............................................................................................................................................................................. M. struthionoptera

8. Stipules 5–8 X 2.5–4.5 mm, triangular, persistent and densely covering the branches just bellow the leaves ............... M. manidea

- Stipules triangular or broadly lanceolate to triangular and acuminate; if persistent, not densely covering the branch ................... 9

9. Leaves congested and densely clustered at tip of branches; stipules broadly lanceolate and acuminate; peduncles up to 9 cm long; filaments pink ............................................................................................................................................................... M. oedoclada

- Leaves congested but not clustered at tip of branches; stipules narrowly triangular; peduncles more than 15 cm long; filaments white ................................................................................................................................................................. M. longepedunculata