Ctenanthe brevibractea F.Fraga & J.M.A.Braga, 2025

Fraga, Fernanda Ribeiro De Mello & Braga, João Marcelo Alvarenga, 2025, Two new species of Marantaceae from Reserva Natural Vale, Espírito Santo state, Brazil, Phytotaxa 682 (1), pp. 112-120 : 113-115

Ctenanthe brevibractea F.Fraga & J.M.A.Braga , sp. nov.

( Figs 1–2 )

Type:— BRAZIL. Espírito Santo: Linhares, Reserva Natural da Vale do Rio Doce , estrada Ceolin , ca. km 0.3, 19º09’45”S, 40º04’24”W, 2 December 2003 (fl., fr.), J.M.A. Braga 7296 et al. ( holotype RB392680 !; isotype CVRD8501 !) .

Diagnosis:— Ctenanthe brevibractea is similar to C. lanceolata Petersen (1890: 163) , but differs in lacking cataphylls, its overall shorter stature, its glabrous leaf sheath ( vs. villose in C. lanceolata ), inflorescence rachis with shorter internodes ( 1–2 mm long vs. 4–10 mm long in C. lanceolata ), its component bracts obovate-acuminate, deciduous ( vs. component bracts lanceolate and persistent in C. lanceolata ), holding 1–2 cymules ( vs. 4–6 cymules in C. lanceolata ), with 1 bracteole per cymule ( vs. 2 bracteoles per cymule in C. lanceolata ), and its flowers with solitary, spathulate outer staminodes ( vs. 2 outer obovate staminodes in C. lanceolata ).

Herb ca. 80 cm tall, erect. Roots unspecialized, rarely villose. Rhizome ca. 5 cm long, not thickened; cataphyll ca. 2 × 1 cm, lanceolate. Leaf simple, antitrope; sheath 12 – 18 × 4 – 6 cm, glabrous, margin cilliate; petiole 48 – 56 cm long, green, glabrous; pulvine 0.9 – 1.5 cm long, adaxially puberulous; blade 15 – 26 × 4.9 – 8.5 cm, lanceolate, base attenuate, apex acuminate, glabrous, adaxially green, abaxially purple. Synflorescence terminal, organized in 3 orders; first order in a 3-nodated floral shoot, with 1 – 2 inflorescences per node, ending up in a fully expanded leaf. Inflorescence made of 10 – 14 components, simple, compressed; peduncle 29 – 34 cm long, green, puberulous; main bract 2.3 – 9 × 0.5 – 0.8 cm, lanceolate, glabrous; rachis 8 – 12 cm long, glabrous; prophyll 1 – 1.5 × 0.5 – 1 cm, lanceolate, glabrous, hyaline, keel ciliate, reddish. Cymule 1 – 2, 2-flowered, subbrachiblastic; component bract 10 – 12 × 10 – 13 mm, obovate, base straight, apex obtuse, glabrous, leathery, hyaline to silvery green, deciduous; prophyll 8 – 13 × 4 – 6 mm, apex acute, base straight, 2-keeled, fibrous, hyaline to stramineous, glabrous; bracteole 0.5 – 0.4 × 0.2 – 0.3, 1 per cymule, lanceolate, hyaline, glabrous. Flower 9.5–10 mm long; sepals 4 – 4.5 × 1.5 – 2 mm, lanceolate, apex acute, hyaline with reddish stains on the apex, glabrous; corolla tube 3–4 mm long, corolla lobe 6–8 × 3–4 mm, lanceolate, apex acute, glabrous, white; outer staminode 1, 5–7 × 2–3 mm, spathulate, white; cucullate staminode 6–8 mm long, glabrous, white; callose staminode 6–8 × 2–3 mm, apex rounded, glabrous, white; stamen 3.5–4 mm long, anther ca. 1.5 mm long, filament ca. 2 mm long, staminal appendage ca. 2 mm long, rudimental, taller than the anther; ovary 1.5–2 mm long, smooth, glabrous; style 5–7 mm long. Capsule 7–8 mm, ellipsoid, pale green, pale yellow when dried, smooth, lustrous, glabrous; seed 4–5 × 5–6 mm reddish, aril white.

Additional specimens ( paratype):— BRAZIL. Espírito Santo: Linhares, Reserva Natural da Vale , Capoeirão, Estrada Aceiro Bobbio , ca. km 0.4, 8 November 2005 (fl.),, D.A. Folli 5117 ( RB854490 !, SAMES03206 !).

Etymology:— The specific epithet “ brevibractea ” means “of short bracts” and refers to the inflorescences of small stature, which have short peduncles.

Notes:— Ctenanthe brevibractea differs from its relatives in its overall short stature and smaller synflorescence peduncles, for lacking cataphylls and presenting synflorescences not subtended by frondose bracts. It is closely related to C. lanceolata because they share leathery component bracts and glabrous, discolour leaf blades. Their differences are indicated in the diagnosis part.

Phenology:— The species sets flowers in November and December. Fruits were recorded in December.

Distribution and habitat:— Ctenanthe brevibractea is known for one single location within the private protected area Reserva Natural Vale ( Fig. 3 ), which is entirely covered by Tableland Forest, a threatened formation of Brazilian Atlantic Forest. The species inhabits a plane terrain, in a shaded spot, near a watercourse.

Figures

FIGURE 1. Holotype of Ctenanthe brevibractea (J.M.A. Braga 7296 et al. [RB!]).

FIGURE 2. Morphology of Ctenanthe brevibractea. A. ovary, B. outer staminode, C. sepals, D. habit, E. inflorescence in detail, F. inflorescence component. Scale bars A: 1 mm, B–C, F: 2 mm, E: 1 cm, D: 5 cm (J.M.A. Braga 7296 et al. [RB!]).

FIGURE 3. Distributtion map of Ctenanthe brevibractea and Saranthe rufopilosa.