Agrostis hyemalis (Walter) Britton, Sterns & Poggenb.
Descripción
Plants perennial, caespitose. Tillers extravaginal, with cataphylls. Culms 15–90 cm long, erect, sometimes shortly decumbent at the base, nodes (2–)3–7, glabrous, internodes glabrous. Leaves basal and cauline; sheaths 5–11 cm long, usually shorter than the internodes, glabrous or sca berulous; ligules 1–7 mm long, longer than wide, dorsally scaberulous, apices rounded to truncate, erose, sometimes acute, often lacerate; blades 3–10(– 15) cm long, 1–2(–3) mm wide, linear, flat, often becoming involute when dry, scaberulous on both surfaces. Panicles 10–30 cm long, (1.5–)4–25(–30) cm wide, open, lax, ovate, exserted from the upper sheaths, sometimes partially included; branches spreading, sometimes ascending, rebranching in the upper third, scaberulous, without spikelets near their base, spikelets clustered at the tips, inferior branches up to 15 cm long; pedicels (0.1–)0.5–2(–3.5) mm long, appressed, scaberulous. Spikelets 1–2(–2.5) mm long, greenish to purplish; glumes subequal to unequal, lanceolate, apices acute to shortly acuminate, 1-veined, scaberulous on the keel, sometimes also on the body, lower glume 1–2(–2.3) mm long, upper glume 0.8–1.9(–2.2) mm long; callus pubescent, with two bunches of trichomes; lemmas 0.8–1.3(–1.4) mm long, elliptic, apices entire, acute to obtuse, sometimes truncate, 5-nerved, veins inconspicuous or prominent, unawned; paleas absent or up to 0.2 mm long, veinless, glabrous; anthers 3, 0.2–0.5 mm long. Caryopsis 0.6–1.2 mm long, elliptic; endosperm soft. 2n= 28 (Harvey 2007).
Anatomy and micromorphology. Leaf blades flat in transversal section; adaxial furrows medium-sized, wide; adaxial ribs rounded; keel absent; first order bundles circular in outline, sheath interrupted adaxially and abaxially, abaxial and adaxial sclerenchyma in girders, narrowing towards the bundle; second order bundles circular in outline, sheath interrupted abaxially, abaxial sclerenchyma absent or in girders, narrowing towards the bundle, adaxial sclerenchyma absent or in strands; intercostal sclerenchyma absent; leaf margins with well-developed sclerenchyma caps, rounded; colorless cells absent (Fig. 15I–K). Lemmas with transversal thickenings oblong, wider than the unthickened portions of the wall; prickle hairs abundant to scarce (Fig. 7H).A
Anatomy and micromorphology. Leaf blades flat in transversal section; adaxial furrows medium-sized, wide; adaxial ribs rounded; keel absent; first order bundles circular in outline, sheath interrupted adaxially and abaxially, abaxial and adaxial sclerenchyma in girders, narrowing towards the bundle; second order bundles circular in outline, sheath interrupted abaxially, abaxial sclerenchyma absent or in girders, narrowing towards the bundle, adaxial sclerenchyma absent or in strands; intercostal sclerenchyma absent; leaf margins with well-developed sclerenchyma caps, rounded; colorless cells absent (Fig. 15I–K). Lemmas with transversal thickenings oblong, wider than the unthickened portions of the wall; prickle hairs abundant to scarce (Fig. 7H).A
Floración
Jan–NovA
Forma de crecimiento
HierbaA
Distribución
Centroamérica presentB, México (Country) native and not endemicC: Aguascalientes present; Baja California present; Baja California Sur present; Chihuahua present; Coahuila de Zaragoza present; Colima present; Distrito Federal present; Durango present; Guanajuato present; Hidalgo present; Jalisco present; Michoacán de Ocampo present; Morelos present; México present; Nuevo León present; Oaxaca present; Puebla present; Querétaro de Arteaga present; San Luis Potosí present; Sinaloa present; Sonora present; Tlaxcala present; Veracruz de Ignacio de la Llave present, North America presentC, South America presentD
Elevación
14–2710 mA
Ecología y Hábitat
Agrostis hyemalis is distributed from Ontario province in Canada to central Mexico, and is also present in the West Indies and Ecuador (Harvey 2007). The records of this species in western North America could represent the confusion with A. scabra (see note below). It has also been reported from Perú (Soreng and Peterson 2003). In the study zone, this species has been collected in southern Arizona and Texas, USA, and in the Mexican states of Aguascalientes, Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Hidalgo, Jalisco, México, Michoacán, Puebla, Querétaro, San Luis Potosí and Sonora (Fig. 18B). It has also been reported from the Mexico City and the states of Colima, Guanajuato, Morelos, Nuevo Leon, Oaxaca, Sinaloa, Tlaxcala and Veracruz (Villaseñor 2016), but no specimens from these states were found. Agrostis hyemalis grows in open areas of temperate forests, with Abies, Juniperus, Pinus or Quercus, cloud forests, rocky areas of grasslands and stream edges. The Texan populations of this species grow in lower elevations than the Mexican ones.A
Tipo de vegetación
Pastizal alpino, Bosque de pino-encino, Bosque de pino, Bosque de neblina/mesófiloA
Categoría IUCN
No incluidaE
Categoría NOM-059-SEMARNAT-2010
No incluidaF
Conservación
Agrostis hyemalis is a widespread species in the study zone. It is represented by 86 collections, with several populations occurring in 15 protected areas. The EOO is 1,491,700 km2 and the AOO is 248 km2. Following the IUCN (2012) criteria, the preliminary assessment category is Least Concern (LC).A
Discusión taxonómica
It has been reported for other regions that the panicles can reach 36 cm long (Harvey 2007). Agrostis hyemalis is often confused with A. elliottiana (see the note under the description of that species). It is also similar to A. scabra, in the panicle branches rebranching in the upper third and somewhat clustered spikelets, and also shares several leaf blade anatomy features. Agrostis hyemalis differs from the latter in the culms with usually more than three nodes, basal and cauline leaves, more clustered and shorter spikelets, of 1–2(–2.5) mm long, and smaller anthers of 0.2–0.5 mm long (vs. culms with usually 1–2(–3) nodes, usually mostly basal leaves, spikelets of 2–3(–3.4) mm long, anthers 0.5–1.4 mm long in A. scabra). The identification of these two species is especially difficult if the plants are not collected with the basal parts.
Phenology. Specimens with spikelets have been collected from January to November, but most of the records are from May (Fig. 10K).A
Phenology. Specimens with spikelets have been collected from January to November, but most of the records are from May (Fig. 10K).A
Bibliografía
A. Vigosa-Mercado, J. L., Delgadillo-Salinas, A., Alvarado-Cárdenas, L. O. & Eguiarte, L. E. 2023: Revision of the genus Agrostis (Poaceae, Pooideae, Poeae) in Megamexico. – PhytoKeys 230: 157-256. http://doi.org/10.3897/3897
B. Harvey, M.J. 2007: Agrostis. In: Barkworth M.E., Capels K.M., Long S, Anderton L.K., Piep M.B. (Eds) Flora of North AMerica North of Mexico (Vol. 24) Oxford University Press, New York, 633-662. http//floranorthamerica.org/Agrostis
C. Vigosa-Mercado, J. L., Delgadillo-Salinas, A., Alvarado-Cárdenas, L. O. & Eguiarte, L. E. 2023: Revision of the genus Agrostis (Poaceae, Pooideae, Poeae) in Megamexico. – PhytoKeys 230: 157-256. http://doi.org/10.3897/3897
D. Soreng, R. J. & Peterson, P. M. 2003: Agrostis. Catalogue of New World Grasses (Poaceae): IV. Subfamily Pooideae. – Contr. U.S. Natl. Herb. 48: 42–89
F. SEMARNAT 2019: MODIFICACIÓN del Anexo Normativo III, Lista de especies en riesgo de la Norma Oficial Mexicana NOM-059-SEMARNAT-2010: 101 pp. – https://www.dof.gob.mx/nota_detalle.php?codigo=5578808&fecha=14/11/2019#gsc.tab=0 [accessed 2023-05-04 06:16]
G. IUCN 2012: Red List Categories and Cirteria: Versión 3.1. Second edition. Internationl Union for Conservation of Nature, Gland Switzerland, 1-32. https://portals.iucn.org/librari/node/10315