Guadua bambuzoniae Londoño, 2024

Londoño, Ximena & Ruiz-Sanchez, Eduardo, 2024, A new species of Guadua (Poaceae: Bambusoideae: Bambuseae: Guaduinae) from the Colombian Amazon, Phytotaxa 638 (3), pp. 227-236 : 228-235

Guadua bambuzoniae Londoño , sp. nov. Figs. 1–3 .

TYPE:— COLOMBIA. Caquetá, Cartagena del Chaira, vereda Los Andes , Finca La Diosa del Bambú , 1º 20’22.7” N, 74º 50’57.4” W, 244 m, 29 September 2022 (fl), X. Londoño & S. Morales 2094 (Holotype COL!, isotype HUAZ!) .

Guadua bambuzoniae differs from G. macrospiculata and G. uncinata in having culms erect at the base and arched from the mid-culm (versus climbing or scandent) culm sheath with usually single falcate auricle (vs. two falcate auricles or auricles absent), lemma with densely ciliate margins (vs. lemmas with smooth margins).

Woody and thorny bamboo. Rhizomes sympodial, pachymorph; the rhizome proper 9–12(–18) × 7–9 cm; apical rhizome segments 1–1.5 cm wide, basal rhizome segments 0.5–1 cm wide; the rhizome neck relatively short, 9–17 cm long; support rhizome necks that push down (or support rhizome necks like “feet”) 2 to 3 on each side of the rhizome, 2–4 cm in diam.; adventitious roots emerging from rhizome segments 20–25 cm long. Culm (4–) 8–10 m tall, 1–4 cm diam., erect at the base, arched in the middle 1/3 and very arched in the apical 1/3, dull green in color, covered by whitish or straw-brown pubescence when young, cylindrical, tapered at apex; internodes (9–)15–24 (–34) cm long, terete, the internodes of the lower 1/3 and the middle 1/3 hollow, those of the upper 1/3 solid, wall thickness in the 1/3 lower portion 1–1.6 cm, wall thickness in the 1/3 middle portion 0.4–0.8 cm; nodes solitary, the single nodal line horizontal, with a band of white, appressed hairs above and below the nodal line, upper band 0.5–0.7 cm wide, lower band 0.5–1.1 cm wide, the supranodal ridge manifest when adult; bud single, triangular, ca. 1.8 × 1.5 cm, covered by a prophyllum; prophyll pubescent, ca. 1.6 cm long, covered by appressed brown hairs, the shoulders of the prophyll ciliate, cilia purple when young then brown. Culm leaves 28–46 cm long, 12–16 cm wide at base, generally surpassing the internode, coriaceous, deciduous, triangular-elongated; sheath 20–33 × 12–16 cm, 2.5 to 2.8 times as long as the blade, abaxially pubescent, covered by two types of hairs: a) hispid, rigid, sparse, antrorse, hyaline or brown hairs, 0.8–1.2 mm long, removable, and b) short, appressed, fine, hyaline hairs, rough to the touch, adaxially glabrous, shiny, marginally ciliate, cilia hyaline or brown, 1–1.2 mm long, bearing a fimbriate auricle or not; auricle falcate, (0.4–)0.7–1 × 0.2–0.3 cm, marginally fimbriate, the fimbriae ivory, shiny, wavy, 0.8–1.2 cm long; inner ligule 1–2 mm long, truncate, straight or slightly incurved at the middle or sigmoidal, usually ending before the margin, adaxially glabrous, shiny, abaxially puberulous, the margin finely ciliolate, cilia very short, hyaline, ca. 0.1 mm long; blade 6–13 × 5–7 cm, triangular, erect, persistent, abaxially glabrescent, covered by short, hyaline, sparse trichomes, adaxially conspicuously nerved and pubescent between nerves, covered by short brown hairs between nerves, densely pubescent at the lower portion, marginally ciliate, cilia 0.5–3 mm long, brown, conspicuous towards the lower portion, mucronate at the apex, the mucro ca. 0.5–1 mm long, strong. Branching intravaginal, typically with one strong dominant branch that comes out ca. 45° angle, occasionally in the upper part developing 2 branches per node, the primary branch 1–1.5 m long, branching orders 2 to 3, developing thorny branches at almost all culm nodes, thorns straight to slightly curved, with (1–)3–6 thorns/node. Foliage leaves borne in lax complements of 7–18 leaves; sheath green when young, later stramineous, abaxially glabrous, ciliate on the margins, bearing fimbriae at the summit, cilia dark, purple to brown, fimbriae 4–8 in number, deciduous, whitish, 8–12 mm long, margins smooth; inner ligule ca. 0.5 mm long, membranaceous, truncate, puberulous, stramineous to dark, margin glabrous; outer ligule 0.1–0.2 mm long, glabrous, shiny, marginally smooth; pseudopetiole 2–5 mm long, glabrous on both surfaces, usually pulvinate; blade (8–)13–18 (–20) × 1–1.5 cm, L: W =8–9:1, linear to linear-lanceolate, 11–19 nerved, marginally scabrous on one side, scabrid on the other side, apically acuminate, adaxially glabrescent, with scattered, sparsely strigose, hyaline hairs ca. 0.5 mm long, with 2–3 rows of prickle-hairs along one edge, abaxially pubescent, covered with scattered, sparse, hyaline or stramineous hairs ca. 0.5 mm long, tessellate, the midnerve prominent in the middle lower portion and slightly asymmetric. Pseudospikelets (3–) 5–8 cm × (3–) 4–5 mm, linear-lanceolate, usually straight sometimes slighly curved dorsally, green with purple when young, later stramineous, consisting of a subtending bract, a prophyll, 2–4(–6) basal gemmiparous bracts, 0–2 sterile lemmas and 6–10(–12) fertile florets, and ending in a rudimentary floret; the terminal pseudospikelet lacking an immediately subtending prophyll; rachilla segments 2.5–5 × 2 mm, pubescent in the middle upper portion, covered by short hyaline hairs, basally glabrous, usually longer between fertile florets, not disarticulating easily at the junction with the floret; subtending bracts varying in size and shape throughout the main axis, with blades varying from fully developed and similar to small foliage leaf blade to reduced apicules, gemmiparous or not, the blades deciduous, the sheath abaxially pubescent towards the margins and glabrous on the dorsal part, ciliolate on the margins and bearing fimbriae or not at the summit; prophyll 1–3 × 1.1–2.5 mm, abaxially and adaxially pubescent in the middle upper portion, basally glabrous, with winged ciliolate keels; basal gemmiparous bracts 2–6, 4–5(–8) × 3–4(–5) mm wide, ovate to ovate-lanceolate, sometimes empty, the apex apiculate with a mucro 0.5–1 mm long, 12–17-nerved, abaxially pubescent towards the margins and otherwise glabrous, adaxially pubescent toward the apex, the rest glabrous, shiny and tessellate, the margins ciliolate; sterile lemmas 8–10 × 6–8 mm, rounded on the back, acuminate at the apex with a strong mucro 0.5–1 mm long, 15–17-nerved, abaxially pubescent towards the margins, dorsally glabrous, adaxially pubescent towards the apex, otherwise glabrous and shiny, marginally densely ciliate, cilia brown in color, always enclosing a rudimentary palea. Florets green and purplish in the middle basal portion, later stramineous, strongly attached at the base with a glabrous green band, ca. 1mm long; lemma 11–13 × 9–11 mm, ovate-lanceolate, rounded on the back, the apex acuminate with a strong mucro ca. 1 mm long, 18–21-nerved, abaxially pubescent towards the margins, otherwise glabrous, green with purple, later stramineous, adaxially pubescent on the apex, otherwise glabrous and shiny, the margins densely ciliate, cilia hyaline or brown, completely embracing the palea; palea 10–12 × 3–5 mm, stramineous, slightly shorter than the lemma, the keel wings laterally exceed the lemma, the sulcus between the keels 2–3 mm wide, 5–8-nerved, with transverse veins, densely pubescent in the 3/4 upper portion, the ¼ lower portion glabrous, enfolding margins puberulous toward the 1/3 upper portion, otherwise glabrous, 5–7-nerved, the keels winged, ending at the apex, the wings 1–1.5 mm wide, 1–3-nerved, adaxially puberulent toward the apex, abaxially glabrous and shiny, finely ciliolate on the margins towards the upper middle part, the cilia hyaline. Lodicules 3, membranous, hyaline, many-nerved, 2.5–3 mm long, 1–1.5 mm wide, short-ciliolate on the upper part of the margin, the apex acute, the anterior pair a little longer and wider than the posterior one. Stamens 6, filaments filiform, free; anthers 6–8 × 0.8–1 mm, sagittate at the base, apiculate at the apex of each theca, ochre. Ovary (immature) 1–2 × 0.5 mm, fusiform, densely hispidulous, with a thickened, glabrous, basal support, 0.8–1 mm long; style 1, ca. 1 mm long, densely antrorse-hispidulous with 3 plumose stigmas 3–4 mm long, hyaline. Fruit not seen.

Etymology:— The specific epithet honors the Bambuzonía Project, funded by the International Bamboo and Rattan Organization—INBAR, and the International Fund for Agricultural Development—IFAD for the Amazon region of Colombia, Ecuador, and Peru. The project was executed between 2020 and 2023 and contributed to the knowledge and development of bamboo in this region.

Habitat and distribution:— This species is distributed in the southeastern part of Colombia, in the department of Caquetá, between 230–250 m asl ( Fig. 4 ). It grows near streams and “cananguchales” (vegetation formations dominated by Mauritia flexuosa Linnaeus (1782: 454)) , in flooded areas, under shade or in full sun ( Fig. 3 ).

Common name:— Guadua .

Uses:— The small straight and tubular portion of the culm and the excess of branches with spines at almost all nodes make Guadua bambuzoniae have little applicability. However, poles can be extracted from the first 2 or 3 basal meters to make fences, to poke or harass cattle, to make furniture, or to replace the decorative poles in the porch of the houses.

Phenology:— Guadua bambuzoniae is able to flowering during a 2 or 3 year period without a dying, according with local people. Flowering culms retain foliage leaves and the fruit production is scarce (Londoño pers. observation).

Additional specimens examined (paratypes):— COLOMBIA. Caquetá, Cartagena del Chaira, Vda. Guadualosa, Finca Camberos , 1°18’45”N, 74°50’59” W, 230.3 m asl, 11 October 2020, X. Londoño 2032 ( HUAZ) ; Finca Camberos 1°18’45” N, 74°50’59.2”W, 28 February 2022, X. Londoño & S. Morales 2093 ( HUAZ) .

Notes:— Guadua bambuzoniae inhabits swampy habitats, as do G. macrospiculata and G. uncinata , species also found in this region of Colombia. With these two species, G. bambuzoniae shares green spikelets with purple lemma when young, a pubescent ovary and style densely covered with hispid and antrorse hairs, and the presence of 3 hyaline plumose stigmas. However, G. bambuzoniae differs from G. macrospiculata and G. uncinata because: a) the culms are erect at the base and arched from the mid-culm (versus climbing or scandent); b) the blade of the culm leaf is not swollen (vs. swollen); c) the culm leaf sheath usually has a falcate and fimbriate auricle (vs. two falcate auricles or auricles absent); and d) the margins of the lemma are densely ciliate (vs. smooth) ( Table 1 ).

Guadua bambuzoniae differs from all other congeners by the following combination of characters: hollow and erect culms at the basal part, and solid and arched culms at the middle and upper part; development of primary branches with thorns at each culm node, oriented at 45° to the central axis; usually with a falcate, prominent, and fimbriate auricle at the upper part of the culm leaf sheath; elongated leaf sheaths, giving a lax appearance to the leaf complement; pseudospikelets linear-lanceolate, usually straight, with the lemmas densely ciliate at the margins and conspicuously mucronate; and paleas with conspicuously winged keels. This adaptation mechanism allows them to thrive in swampy environments and face these types of challenges that nature offers.

Like many species in this Amazon region of Colombia, Guadua bambuzoniae is endangered due to deforestation in its habitat. It is an ecologically important species for the conservation of swampy areas called “canaguchales” or “aguajales”, and for the biological diversity that is housed there.

Figures

FIGURE 1. Guadua bambuzoniae. A. Foliage leaf complement. B. Detail of the apical region of the leaf sheath, adaxial view. C. Nodal region of the culm with solitary bud. D. Thorny branch segment. E. Culm leaves. F. Section of culm leaves upper portion showing blade and inner ligule. Based on: A–B: Londoño & S. Morales 2094; C–F: Londoño 2032.

FIGURE 2. Guadua bambuzoniae. A. Synflorescence terminating a leafy branch. B. Pseudospikelet. C. Basal gemmiparous bract. D–E. Lemma, adaxial and abaxial view. F. Palea, close ventral view, G. Palea, abaxial view with winged keels. H. Androecium of 6 stamens surrounding the gynoecium. I. Stamen. J. Lodicules, K. Inmature gynoecium. Based on: Londoño & S. Morales 2094.

FIGURE 3. Guadua bambuzoniae. A. Habitat and habit. B. Pachymorph rhizome with the lowest culm internode. C. Culm leaf adaxial surfaces from two different portions of the culm. D. Node showing a single bud and supra- and infranodal white bands. E. Synflorescence showing 3 pseudospikelets. Pictures by Ximena Londoño.

FIGURE 4. Geographical distribution map of Guadua bambuzoniae. Country code: CO = Colombia, BR = Brazil, EC = Ecuador, PA = Panama, PE = Peru and VE = Venezuela.