Guadua Kunth, 1822

Ruiz-Sanchez, Eduardo, Clark, Lynn G., Londoño, Ximena, Mejía-Saulés, Teresa & Rodríguez, Gilberto Cortés, 2015, Morphological keys to the genera and species of bamboos (Poaceae: Bambusoideae) of Mexico, Phytotaxa 236 (1), pp. 1-24 : 16-17

Guadua Kunth

Rhizomes pachymorph with short to elongated necks; culms hollow or rarely solid, erect to apically arching; usually with supra- and infra-nodal bands of short, soft white to tan hairs present in the nodal region; culm leaf sheaths well developed, auricles present or absent, fimbriae present or absent, oral setae absent; culm leaf blades erect, persistent or rarely deciduous; branching intravaginal or extravaginal; nodes with one central bud developing into 1 main central branch bearing several smaller secondary branches, thorns usually present; synflorescences terminal, paniculate; pseudospikelets usually stalked, forming sparsely or densely crowded aggregations, comprising 1 subtending bract, 1 prophyll, one to several gemmiparous bracts, sometimes none but typically 1 to several glumes, and few to several functional florets, and one rudimentary anthecium; lemma apiculate, glabrous or velutinous; lodicules 3; stamens 6 (3 in G. longifolia ); stigmas 3; fruit a basic caryopsis ( Fig. 5A–F , 9B ).

1. Culm leaves with blades deciduous, auricles absent, fimbriae absent; foliage leaf blades linear-lanceolate; culms 3–12 m tall, 2–7 cm in diameter, bands of short, soft white or tan hairs both above and below the nodal line inconspicuous or absent....................2

1. Culm leaves with blades persistent, auricles present or absent, fimbriae present or absent; foliage leaf blades ovate-lanceolate; culms 5–20 m tall, 5–20 cm in diameter, bands of short, soft white or tan hairs both above and below the nodal line conspicuous.............................................................................................................................................................................................................3

2. Nodal region glabrous, dark green and shiny, supranodal band of hairs absent ; culm leaves with an asymmetrical sigmoidal inner ligule, blade triangular, up to 2/3 the length of the sheath; pseudospikelets 5–6 cm long; lemmas awned; stamens 3....................... ......................................................................................................................................................................................... G. longifolia Mexico, Guatemala and Belize; Campeche , Chiapas, Tabasco, Veracruz ; 0– 400 m.

2. Nodal region with a supra- and infranodal band of withish and unconspicuos hairs present; culm leaves with deciduous blades, blades triangular, usually symmetrical to asymmetrical with one side extending downward along the length of the sheath, up to 1.2 to 1.5 the length of the sheath; pseudospikelets 3–4 cm long; lemmas awnless; stamens 6 .......................................... G. paniculata Mexico to Bolivia; Pacific slopes of Mexico; 100–1000 m.

3. Culms solid or rarely hollow, with thick walls; the branches developing or not few thorns; culm leaves strongly auriculate-fimbriate at the summit.................................................................................................................................................................. G. inermis Endemic to Mexico: Chiapas, Oaxaca, Tabasco, Campeche, Veracruz ; 0– 900 m.

3. Culms with well-developed thorns, hollow with thick walls; culm leaves with fimbriate auricles present or absent.......................4

4. Supra- and infra-nodal bands more or less in equal size; auricles on the culm leaves present or absent..........................................5

4. Supra- and infra-nodal bands unequal in size; auricles on the culm leaves present...........................................................................6

5. Culm leaves with the sheaths 5 to 10 times larger than the blade, auricles absent, fimbriae absent at the culm leaf sheath summit; primary bud with prophyll pubescent; foliage leaf blades (15–) 18–23 cm long, 1.6–4.2 cm wide ................................ G. aculeata Mexico to Venezuela; Chiapas, Puebla, Veracruz; 0– 300 m.

5. Culm leaves with the sheaths 2.5 to 3 times larger than the blade, falcate auricles present at the culm leaf sheath summit ; primary bud with prophyll glabrous; foliage leaf blades (7–) 11–16 cm long, (0.9–) 1.1–1.6 cm wide ........................................ G. tuxtlensis Endemic to Mexico; Veracruz; 0– 360 m.

6. Infra-nodal bands narrower than the supra-nodal bands; culms covered with short appressed, whitish, soft hairs; branches of the basal nodes with thorns; pseudospikelets glabrous and maculate............................................................................... G. amplexifolia Mexico to Venezuela; Campeche, Chiapas, Quintana Roo, Puebla, Tabasco, Veracruz; 0– 600 m.

6. Infra-nodal bands twice the width of the supra-nodal bands ; culms covered with sericeous, long, hyaline, soft hairs; pseudospikelets densely velutinous........................................................................................................................................................ G. velutina Endemic to Mexico; Hidalgo, Puebla, San Luis Potosí, Tabasco, Veracruz; 0– 900 m.

Figures

FIGURE 5.A. Guadua tuxtlensis, nodal region showing a thorn at the base of the primary branch. B. Guadua inermis, nodal area showing the primary branch base and supra- and infranodal bands of white hairs. C. Guadua aculeata, showing bud. D. Guadua longifolia, showing pseudospikelets. E. Guadua paniculata, showing branches and thorns. F. Guadua aculeata, showing pseudospikelets with stamens and stigmas. Photos by E. Ruiz-Sanchez.

FIGURE 9. Cultived woody bamboos. A–B. Bambusa vulgaris var. vittata, yellow culms with green stripes. B. Guadua angustifolia culms. C. Phyllostachys aurea, showing ventricose basal nodes.. D. Phyllostachys bambusoides, diffuse culms. E. Bambusa oldhamii, showing glaucous culms and culm leaves. Photos by E. Ruiz-Sanchez.