Chusquea subg. Swallenochloa (McClure, 1973) Clark, 1997

Pianissola, Evandro Machado, Parma, Daniele F., Santos-Gonçalves, Ana Paula & Clark, Lynn G., 2018, Two new species of Chusquea subg. Swallenochloa (Poaceae: Bambusoideae: Bambuseae) from Minas Gerais, Brazil, and complete description of C. caparaoensis, Phytotaxa 358 (3), pp. 235-250 : 247

Key to the species of Chusquea subg. Swallenochloa in Brazil (based on vegetative specimens)

1. Foliage leaf sheaths deciduous from the lower nodes of the subsidiary branches.............................................................................2

- Foliage leaf sheaths persistent ............................................................................................................................................................8

2. Central bud/branch flanked by 1 ‒ 3 subsidiary buds/branches on each side in one linear row; branching intravaginal....................3

- Central bud/branch subtended by 1 ‒ 2 rows of subsidiary buds/branches, or subtended by 4 ‒ 5 tiers and flanked by 4 ‒ 5 subsidiary buds/branches; branching extravaginal..............................................................................................................................................4

3. Foliage leaf blades on vegetative branches 0.2–0.4 mm wide, L:W = 10.3 ‒ 20................................................................ C. fruticosa

- Foliage leaf blades (0.5 ‒) 0.8 ‒ 1 mm wide, L:W = 5.5 ‒ 8.6............................................................... C. windischii Clark (1992: 405)

4. Central bud/branches flanked by slightly smaller subsidiary buds/branches, and subtended by 4 ‒ 5 rows of medium to small sized subsidiary buds/branches; foliage leaves with inner ligules 0.2 ‒ 0.5 (‒ 1) mm long, truncate, and sheaths mottled....... C. juergensii

- Central bud/branch subtended, not flanked, by 1 or 2 rows of subsidiary buds/branches; foliage leaves with inner ligules 0.5 ‒ 4.0 mm long, rounded or slightly rounded, and sheaths uniform in color, not mottled...........................................................................5

5. Central bud nearly circular; culm leaf blade narrowly triangular, erect becoming reflexed, caducous; smaller subsidiary branches 4 ‒ 10 per node ................................................................................................................................... C. nudiramea Clark (1992: 415)

- Central bud triangular; culm leaf blade triangular, erect, persistent; smaller subsidiary branches 15 ‒ 80 per node ..........................6

6. Central bud/branch subtended by 1 ‒ 2 more or less linear rows of subsidiary buds/branches; foliage leaf blades 0.18 ‒ 0.25 cm wide, L:W = (22.5 ‒) 25.6 ‒ 33............................................................................................................................................... C. caparaoensis

- Central bud/branch subtended and partially encircled by 1 ‒ 2 rows of subsidiary buds/branches; foliage leaf blades (0.2 ‒) 0.5 ‒ 0.9 (‒ 1.2) cm wide, L:W = (4 ‒) 7.5 ‒ 24....................................................................................................................................................7

7. Culm leaf sheaths 1 ‒ 5 times as long as the blade; smaller subsidiary branches 15 ‒ 40 per node; foliage leaf blades (0.3 ‒) 0.5 ‒ 0.9 (‒ 1.2) cm wide, L:W = (4 ‒) 7.7 ‒ 15, base attenuate to rounded-attenuate ........................................................................................... .................................................................................................................... C. mimosa McClure & Smith (1967: 37) subsp. mimosa

- Culm leaf sheaths (3.5 ‒) 12 ‒ 27.5 (‒ 50) times as long as the blade; smaller subsidiary branches 45 ‒ 80 per node; foliage leaf blades (0.2 ‒) 0.4 ‒ 0.7 cm wide, L:W = 10.6 ‒ 24, base attenuate............................................. C. mimosa subsp. australis Clark (1992: 414)

8. Branching extravaginal; subsidiary branches (12 ‒) 20 ‒ 60 per node, more or less horizontally exserted, in 2 ‒ 6 rows, constellate ... ............................................................................................................................................................................................................9

- Branching intravaginal; subsidiary branches 3 ‒ 20 (‒ 30) per node, erect, in 1 row, linear ..............................................................10

9. Foliage leaf blades 1.3 ‒ 3.7 cm long, 0.2 ‒ 0.4 cm wide; subsidiary branches 3 ‒ 15 cm long, (12 ‒) 20 ‒ 45 per node, the central branch usually developing, robust; nodes with the supranodal ridge prominent; subsidiary buds in 2 rows in a crescent-shaped arrangement; culms 1 ‒ 2 (‒ 3.5) m tall......................................................................................................... C. heterophylla Nees (1835: 488)

- Foliage leaf blades 0.8 ‒ 2 cm long, 0.1 ‒ 0.2 cm wide; subsidiary branches 1.5 ‒ 4 cm long, 30 ‒ 60 per node, the central branch usually not developing; nodes with the supranodal ridge obscure; subsidiary buds in 5 or 6 rows in a triangular arrangement; culms 0.5 ‒ 1 m tall.................................................................................................. C. microphylla (Döll in Martius 1880: 207) Clark (1992: 420)

10. Central branch curving away from the main culm, sometimes more or less erect at the base before curving ................................11

- Central branch erect and more or less appressed to the main culm for its full length......................................................................13

11. Foliage leaves 8 ‒ 10 (‒ 13) per complement; foliage leaf blades 0.3 ‒ 0.4 cm wide; Serra do Ibitipoca , Minas Gerais ........................ ....................................................................................................................................................................................... C. riosaltensis

- Foliage leaves 3 ‒ 8 per complement; foliage leaf blades 0.4 ‒ 1 cm wide; Morro da Igreja , Santa Catarina ....................................12

12. Culms ca. 1 m tall; subsidiary branches 4 ‒ 11 cm long; central branch strongly sinuous ............................................... C. windischii

- Culms 1 ‒ 1.5 m tall; subsidiary branches 4 ‒ 16 cm long; central branch gently curved....................................................................... .......................................................................................................................................... C. hatschbachii Clark & Blong (2009: 29)

13. Foliage leaf blades 0.06 ‒ 0.25 (‒ 0.4) cm wide, L:W = 17 ‒ 60, the base attenuate............................................................................14

- Foliage leaf blades 0.35 ‒ 1.1 cm wide, L:W = 6.5 ‒ 14, the base truncate-rounded to rounded-attenuate ........................................16

14. Central bud/branch flanked by subsidiary buds/branches; foliage leaf blades L:W = (25 ‒) 33 ‒ 60; culm leaf sheaths fused at the base for 0.3 ‒ 1.5 cm, the blade usually not distinguishable from the sheath ........................................... C. nutans Clark (1992: 398)

- Central bud/branch subtended by subsidiary buds/branches; foliage leaf blades L:W = 8 ‒ 31; culm leaf sheaths not fused at the base, blades distinguishable from the sheath....................................................................................................................................15

15. Internodes sulcate, 14 ‒ 20 cm long; culm leaves deciduous, (20 ‒) 33 ‒ 55 cm long, extending (1.4 ‒) 2 ‒ 3 times the internode length, abaxially with setose trichomes at the base; foliage leaf blades L:W = (8 ‒) 10 ‒ 17.3 .................................................... C. imbricata

- Internodes terete, 3 ‒ 11 cm long; culm leaves persistent, 5.3 ‒ 14.2 cm long, usually shorter than or equaling one internode but sometimes longer, never more than 1.3 times the internode length, abaxially glabrous or retrorsely scabrous; foliage leaf blades L: W = 17 ‒ 31 .............................................................................................. C. pinifolia (Nees in Martius 1829: 525) Nees (1835: 490)

16. Foliage leaf blades 0.8 ‒ 1.1 cm wide .............................................................................. C. sclerophylla Döll in Martius (1880: 200)

- Foliage leaf blades 0.35 ‒ 0.5 (‒ 0.7) cm wide....................................................................................................................................17

17. Foliage leaves 10 ‒ 13 per complement; foliage leaf blades with L:W = 6.5 ‒ 11; foliage leaf sheaths glabrous to softly pubescent toward the apex; culm leaves abaxially glabrous............................................................................ C. baculifera Silveira (1919: 99)

- Foliage leaves 19 ‒ 24 per complement; foliage leaf blades with L:W = 11 ‒ 14; foliage leaf sheaths pubescent-hispid between the nerves; culm leaves abaxially pubescent................................................................................................. C. erecta Clark (1992: 397)