Eremocaulon capitatum ( Trinius 1835a: 626 ) Londoño, 2002

Lopes-Neto, Raimundo Balieiro & Viana, Pedro Lage, 2022, Flora of the Serra do Cachimbo (Eastern Amazon, Brazil): Bambusoideae (Poaceae), including the description of two new species, Phytotaxa 550 (2), pp. 99-129 : 109-110

Eremocaulon capitatum ( Trinius 1835a: 626) Londoño in Londoño & Clark (2002: 714)

≡ Bambusa capitata Trinius (1835a: 626) . Fig. 2 J–N .

Lectotype (designated here):— BRAZIL. In ripa flum. Pardo Bras, Riedel s.n. [lectotype LE-TRIN-3211.02 (photo!), isolectotypes LE-TRIN-3211.01 (photo!), MO-2875457 (photo!), P-00633835 (photo!), US-00026623 -fragm. ex LE (photo!)].

Rhizomes pachymorph, necks 2–4 cm long. Culms 5–8 m tall, 1.2–3.4 cm in diameter, erect at first then arching at the apex, internodes 15–46.6 cm long, with a soft central pith when young, solid when old, glabrescent, dark green, infranodal bands of white trichomes 0.5–0.6 cm long, supranodal bands 1.5–2 cm long, both with adpressed, silky and wavy short trichomes; primary buds subequal, prophyll not seen; nodes dark brown, glabrous, horizontal, supranodal ridge inconspicuous. Branch complement with one dominant branch 0.5–1 m long, ca. 5 mm in diameter, with 4–8 secondary branches at its base, 40–60 cm long, ca. 2 mm in diameter, internodes 18–24 cm long. Culm leaves longpersistent; sheath 11–15 × 6– 6.7 cm, longer than the blade, ochraceous or stramineous, with pinkish spots, adaxially glabrous, abaxially glabrescent, with silky adpressed trichomes, margins densely ciliate, the cilia rubbing off easily; auricles 0.4–0.6 cm, brown; fimbriae 1.6–2.2 cm long, scabrid, with silky adpressed trichomes, golden; inner ligules 0.6–1 mm, symmetrical, membranous; blades 10.2–10.4 × 0.6–1.6 cm, ovate-lanceolate, stramineous, abaxially densely pubescent, with silky trichomes, adaxially waxy, glabrescent, with golden trichomes, margins fimbriate to ciliate, apex acuminate. Foliage leaves 6 – 9 per complement; sheath 4–6 × 4 cm, green, hispidulous, with silky wavy trichomes, overlapping margins smooth, underlapping margins densely ciliate; auricles present, tongue-shaped, ca. 0.5 cm long; fimbriae ca. 0.2 cm long, straight at the base and sinuous toward the apex, stramineous (in siccus); inner ligules ca. 0.6– 0.7 cm, symmetrical, membranous; outer ligules 0.14–0.18 cm, asymmetrical, rim-like shaped, hispidulous, with silky erect trichomes, margins ciliate; pseudopetioles 1–2 cm, flat, glabrous; blades 15–33 × 4.5–15 cm, linear-lanceolate, green, glabrous on both surfaces or sparsely hairy on the abaxial surface, 11–13-nerved, midnerve strongly excentric, 5–7 nerves on one side and 4–5 on the other side, base truncate, margins scabrous, apex acuminate. Synflorescence 34.5–42 cm long (primary branches), ca. 6 capitate coflorescences, each coflorescence with 6–8 pseudospikelets, main axis pubescent basally and apically, glabrous in the middle portion; subtending bracts ca. 13 × 4 mm, tardily caducous, ovate-lanceolate, abaxially glabrous, adaxially pubescent toward the apex, overlapping margins ciliate, apex acute. Pseudospikelets 12–13 × 1.8–3 mm, ovate-lanceolate to linear-lanceolate; prophyll not seen; gemmiparous bracts 2–4 × 0.5–4 mm, the apical ones larger than the basal ones, triangular, 10-nerved, stramineous (in siccus), glabrous, overlapping margins ciliate, apex acute or shortly mucronate; sterile lemma 8–10 × 3–4 mm, ovate-lanceolate, 18- nerved, stramineous (in siccus), glabrous toward the apex, margins glabrous, apex acute; rachilla internodes between the fertile anthecia ca. 1.5 mm long, pubescent, straight. Fertile anthecium ca. 9–10 × 1–2 mm, ovate-lanceolate; lemma 14–19-nerved, abaxially waxy, glabrous, adaxially glabrous except pubescent at the tip, with adpressed transparent trichomes, overlapping margins glabrous or ciliolate, apex mucronate, ca. 0.5 mm long; palea 12–18-nerved, the wings of the palea keels exceeding the margins of the lemma, enfolding margins glabrous except apically puberulous and waxy, apex bifid; lodicules 3, subequal, ca. 2 × 1 mm, deltoid, glabrous, apex rounded; stamens 6, filaments ca. 1 mm long, pubescent, anthers ca. 8 mm long, yellowish (in siccus); ovary ca. 1 mm long, elliptic, apically hispidulous, style ca. 3 mm long, hispidulous, stigmas 2. Caryopsis not seen.

Specimens examined: — BRAZIL. Pará : Altamira , Reserva Biológica Nascentes da Serra do Cachimbo, Cachoeira do Curuá, ca. 400 m da BR- 163, 368 m, 8°44’08.3”S, 54°57’43.6”W, 30 September 2019, Pastore et al. 1175 ( MG) ; Ponte sobre Rio Curuá, 9°04’15.8”S, 54°46’27.7”W, 28 September 2019, Maciel-Silva et al. 478 ( MG) ; Ramal principal da REBIONSC, entrada a 65 km ao sul de Cachoeira da Serra, 589 m, 9°04’26.6”S, 54°45’18.3”W, 25 May 2021, Lopes-Neto et al. 683 ( MG) . Novo Progresso , Campo de Provas Brigadeiro Velloso, Rio Braço Norte, cerca de 600 m a norte da ponte, 465 m, 9°21’16.6”S, 54°54’17.0”W, 26 September 2019, Pastore et al. 1133 ( MG) .

Distribution and habitat: —This species is endemic to the Brazilian Central Planalto, in the states of Goiás, Mato Grosso and Mato Grosso do Sul ( Londoño & Clark 2002). This is the first record for the state of Pará. Eremocaulon capitatum occurs in gallery forests and mata ciliar in sandy soils, at 300 to 900 meters ( Londoño & Clark 2002). In Serra do Cachimbo, this species was found in riparian forests of Cerradão and Open ombrophilous forest, along the margins of the Braço Norte (CPBV) and Curuá (REBIONSC) rivers.

Comments: — Eremocaulon capitatum is distinguished from its congeners by the culms 5–8 m tall, the presence of infra- and supranodal bands of white trichomes, culm leaf sheaths abaxially glabrescent, margins densely ciliate, and midnerve of the foliage leaves strongly excentric. In the Serra do Cachimbo, it differs from Guadua paniculata Munro (1868: 85) , which also has infra- and supranodal bands of white trichomes on the culms, by the branch complement without thorns (vs. bearing thorns), persistent culm leaves, with blades reflexed, ovate-lanceolate (vs. caducous culm leaves, blades erect, triangular) and synflorescences composed of 6 capitate coflorescences, pseudospikelets 12–13 × 1.8–3 mm and palea with enfolding margins glabrous except apically puberulous and waxy (vs. 4–8 paniculate coflorescences, pseudospikelets ca. 26 × 4 mm and palea margins glabrous).

The basionym of Eremocaulon capitatum , Bambusa capitata Trinius (1835: 626) , was described based on one specimen collected in Brazil by Ludwig Riedel, which contains the annotation “in ripa flum. Pardo Bras.”. The C.B. Trinius Gramineae Herbarium at LE possesses three sheets in the folder labeled “ Bambusa capitata ”: LE-TRIN-3212.01, LE-TRIN-3211.01, and LE-TRIN-3211.02 (Soreng et al. 1994). The specimen LE-TRIN-3212.01 is a duplicate of the C.L. Willdenow herbarium (B-W-07013-01 0), with the annotations “ Nastus capitatus” Kunth (1830: 325) and “ B. capitata ” [which can be Bambusa capitata (Kunth 1830: 325) Willdenow ex Ruprecht (1840: 133) or Beesha capitata (Kunth 1830: 325) Munro (1868: 145) ], both synonyms of Cathariostachys capitata (Kunth 1830: 325) Soetjami Dransfield (1998: 391) , a woody bamboo endemic of Madagascar (Dransfield 1998). The specimens LE-TRIN-3211.01 and LE-TRIN-3211.02 are syntypes and clearly fit the morphology described in the protologue of Bambusa capitata Trinius (1835: 626) , but only the latter has the indication of the type-locality “in ripa flum. Pardo Bras.”.

Londoño & Clark (2002) indicated Riedel s.n. (LE) as the holotype of Bambusa capitata Trinius (1835: 626) and considered Riedel 430 (G-00099474, K-000433088, NY-00862741, and US-00026623-fragm. ex LE) as “possible isotypes”. The status of holotype indicated by Londoño & Clark (2002) is not accurate since there are two specimens (syntypes) of Riedel s.n. at LE (LE-TRIN-3211.01 and LE-TRIN-3211.02). Thus, that indication can not be considered a lectotypification according to Art. 7.11 and Art. 9.23 of the Code ( Turland et al. 2018). Moreover, among the specimens referred to as possible isotypes by Londoño & Clark (2002), only US-00026623, a fragment from LE, is indeed part of the type collection. The specimens labeled Riedel 430 (G-00099474, K-000433088, NY-00862741) do not show any evidence that they belong to the type collection.

Thus, we conclude that Riedel s.n. is represented by five sheets (LE-TRIN-3211.01, LE-TRIN-3211.02, MO-2875457, P-00633835, and US-00026623), and designate the specimen LE-TRIN-3211.02 as the lectotype of Bambusa capitata Trinius (1835: 626) because it better fits the protologue. Besides including the exact information of the type locality “in ripa flum. Pardo Bras.”, it is deposited in the principal collection of Ludwig Riedel (Stafleu & Cowan 1976).

Figures

FIGURE 2. Field photographs of bamboos from Serra do Cachimbo. A–C. Actinocladum verticillatum: A–B. Habit. C. Culm leaves. D–I. Arthrostylidium simpliciusculum: D. Habit. E. Branch complement. F. Culm leaf sheath margins. G. Culm leaf apex. H. Foliage leaf complement. I. Foliage leaf fimbriae. J–N. Eremocaulon capitatum: J. Habit. K. Infra- and supranodal bands of trichomes and culm leaves. L. Foliage leaf fimbriae. M. Synflorescence. N. Pseudospikelets. O–R. Guadua paniculata: O. Habit. P. Infra- and supranodal bands of trichomes and thorns. Q. Foliage leaf complement. R. Culm leaves. Photos: P.L.Viana (A–K, M–O, R) and M.Pastore (L, P).