Staurogyne rubescens Braz & Monteiro (2005: 55)

Braz, Denise Monte & Monteiro, Reinaldo, 2017, Taxonomic Revision of Staurogyne (Nelsonioideae, Acanthaceae) in the Neotropics, Phytotaxa 296 (1), pp. 1-40 : 30

21. Staurogyne rubescens Braz & Monteiro (2005: 55) . Type: — BRAZIL. Rio de Janeiro: Paraty, “subida para o Cuscuzeiro, 500 m., APA-Cairuçu”, March 1995, M.G. Bovini et al. 724 (holotype: RB!). (Fig. Braz & Monteiro 2005: 56) ( Fig. 2E )

Herb 50 − 90 cm tall, rarely branched, sparsely pilose with simple trichomes, sometimes glandular. Petiole 6 − 20 mm long; blade elliptic, 3 − 10.3 × 1.1 − 3.2 cm, apex acute to slight-acuminate, base attenuated to acute, adaxially glabrous, rarely with simple trichomes in the mid vein, abaxially with simple and disc-shape trichomes restricted to the veins. Inflorescence in lax, terminal, bracteates raceme, 3.3 − 7.3 cm long, peduncle 2.1 − 2.9 cm long; flowers opposite; rachis, bract and bracteoles sparsely simple and glandular pilose; bract and bracteoles green, bract elliptic to lanceolate-elliptic, 0.8 − 15 × 2.5 − 6 mm, the smallest ones toward the apex, 1-nerved, bracteoles lanceolate, 4 − 12 × 0.8 − 2.1mm. Pedicel 4 − 9 mm long; calyx slightly pinkish to vinaceous, sparsely pilose with glandular trichomes, usually ciliate, posterior segment 12 − 27 × 2 − 3.5 mm, 3-nerved, lateral pair of segments 10 − 19 × 0.5 − 1.5 mm, anterior pair of segments 12 − 20 × 1.3 − 2 mm; corolla red to slightly pinkish, 2.9 − 3.4 cm long, basal tube 2.5 − 6 mm long, anterior lobe 2.7 − 5 long, externally with simple and glandular trichomes, usually dense, internally glabrous; posterior stamens 1.7 − 2.6cm long, anterior stamens 1.8 − 2.7 cm long, staminode 1.5 − 2.8 mm long; ovules 16 − 18 per locule, posterior lobe of the stigma divided to slightly concave. Capsule 14 − 16.5 × 3.5 − 4 mm, sparsely glandular pilose.

Specimens examined:— BRAZIL. Rio de Janeiro: Parati, Praia Negra, Pico do Cairuçu, 25 March 1992, Farney et al. 3123 (RB). São Paulo: Ubatuba, próximo à divisa com São Luiz do Paraitinga, 3 April 2002, Braz et al. 77 (HRCB), 3 April 2002, Braz et al. 78 (HRCB).

Distribution and habitat:— Staurogyne rubescens is endemic to the Atlantic rain forest in the Serra do Mar, only recorded from the southern portion of the State of Rio de Janeiro to the north of São Paulo State. It was found in well protected Conservation Units, in the APA Cairuçu, the Joatinga Ecological Station and the Serra do Mar State Park ( Braz and Monteiro 2005), occurring in shady habitats between 500 − 1080 m elevation above sea level.

Phenology:— It was collected with flowers and fruits in March and April.

Taxonomic notes:— Staurogyne rubescens is recognized especially by the lax terminal raceme, with bracts and bracteoles green and flowers with green calyx and red pinkish corolla. S. rubescens and S. itatiaiae are the only Americans representatives of the genus with red flowers and tubular corolla. In addition to the distinctive occurrence areas, S. rubescens differs from S. itatiaiae by the inflorescence in lax raceme (not dense spikes) and the bracts and bracteoles leaf-like (not petal-like). S. rubescens also resembles S. minarum in the terminal lax raceme and the green bracts and bracteoles, but it is easily distinguished from the latter by the herbaceous (not shruby) habit and the red (not yellow to greenish yellow) corolla. Furthermore, both have limited and quite distinct areas of occurrence.

Figures

FIGURE 2. Staurogyne with tubular corolla. A–B. S. anigozanthus. C. S. vauthieriana. D. S. itatiaiae.E. S. rubescens. (photoed by the authors)