Agrostis stolonifera L., Sp. Pl. 1: 62. 1753.

Vigosa-Mercado, J. Luis, Delgado-Salinas, Alfonso, Alvarado Cardenas, Leonardo O. & Eguiarte, Luis E., 2023, Revision of the genus Agrostis (Poaceae, Pooideae, Poeae) in Megamexico, PhytoKeys 230, pp. 157-256 : 157

15. Agrostis stolonifera L., Sp. Pl. 1: 62. 1753.

Figs 4N , 30B , 33

= Agrostis palustris Huds., Fl. Angl. (Hudson) 27. 1762. Agrostis stolonifera L. var. palustris (Huds.) Farw., Rep. (Annual) Michigan Acad. Sci. 21: 351. 1920. Agrostis polymorpha Huds. var. palustris (Huds.) Huds., Fl. Angl. (ed. 2) 1: 32. 1778. Agrostis alba L. var. palustris (Huds.) Pers., Syn. Pl. 1: 76. 1805. Apera palustris (Huds.) Gray, Nat. Arr. Brit. Pl. 2: 148. 1821. Agrostis stolonifera L. subsp. palustris (Huds.) Tzvelev, Novosti Sist. Vyssh. Rast. 8: 58. 1971. Type: England. 119. Gramen Miliac. maj. panic. viridi. In Herb. Petiver (lectotype, designated by Widén (1971: 77): BM).

Agrostis polymorpha Huds. var. stolonifera (L.) Huds., Fl. Angl. (ed. 2) 1: 31. 1778.

Decandolia stolonifera (L.) Bastard, Essai Fl. Maine et Loire 29. 1809.

Vilfa stolonifera (L.) P. Beauv., Ess. Agrostogr. 16. 1812.

Milium stoloniferum (L.) Lag., Elench. Pl. Nov. 10. 1816.

Agrostis alba L. var. stolonifera (L.) Sm., Engl. Fl. 1: 93. 1824.

Agrostis vulgaris With. var. stolonifera (L.) G. Mey., Chloris Han.: 657. 1836.

Agrostis vulgaris With. var. stolonifera (L.) W.D.J. Koch, Syn. Fl. Germ. Helv. 782. 1837.

Agrostis tenuis Sibth. var. stolonifera (L.) Podp., Kvetena Moravy (Prace Marav. Prir. Spolc.) 6: 354. 1926.

Agrostis palustris Huds. var. stolonifera (L.) Druce, Fl. Oxfordshire (ed. 2) 473. 1927.

Agrostis capillaris L. var. stolonifera (L.) Druce, List Brit. Pl. 126. 1928.*

Type.

Herb. A. van Royen s.n. (lectotype, designated by Widén (1971: 77): L (L0059234 [image!])).

Description.

Plants perennial, stoloniferous. Tillers extravaginal, with cataphylls. Stolons up to 1(-2) m long. Culms (8-)15-60 cm long, erect, decumbent at the base, nodes (2-)3-7, glabrous, lower nodes rooting, internodes glabrous. Leaves mostly cauline; sheaths 2.5-8 cm long, usually shorter than the internodes, glabrous or scaberulous; ligules 1-7 mm long, longer than wide, dorsally scaberulous, apices rounded to truncate, erose to lacerate; blades (1-)2-10 cm long, (1-)2-6 mm wide, linear, flat, becoming convolute when dry scaberulous on both surfaces. Panicles (3-)4-20 cm long, 0.5-3 cm wide, open at anthesis, becoming contracted, dense, lanceolate, sometimes spiciform; branches appressed to ascending, branching from below mid-length, scaberulous, inferior branches 2-6 cm long, lateral branches often with spikelets near their base; pedicels 0.5-3.3 mm long, appressed to ascending, scaberulous. Spikelets 1.6-2 (-3) mm long, greenish, often tinged with purple; glumes subequal to unequal, lanceolate, apices acute to shortly acuminate, 1-veined, scaberulous on the keel, lower glume 1.6-2 (-3) mm long, upper glume 1.4-2(1.6-2 (-3) mm long; callus puberulous, with 2 bunches of short trichomes, sometimes inconspicuous; lemmas 1.4-2 mm long, elliptic to oblong, apices entire, acute to obtuse, sometimes toothed, 3(5)-veined, veins inconspicuous or prominent distally, unawned, rarely awned from above mid-length, awn up to 1.5 mm long, inserted 0.8-1.5 mm above the base, straight or weakly geniculate; paleas present, 0.7-1.4 mm long, 2-veined, glabrous; anthers 3, 0.9-1.5 mm long. Caryopsis 0.9-1.3, elliptic; endosperm solid. 2n= 28, 35, 42 ( Harvey 2007).

Anatomy and micromorphology.

Leaf blades flat to convolute in transversal section; adaxial furrows medium-sized to deep, wide; adaxial ribs rounded; keel absent; first order bundles circular to slightly elliptical 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 and adaxial sclerenchyma in strands; intercostal sclerenchyma absent; leaf margins with well-developed sclerenchyma caps, rounded; colorless cells absent (Fig. 31D, E ). Lemmas without transversal thickenings, prickle hairs abundant to scarce (Fig. 32B ).

Distribution and habitat.

Introduced. Agrostis stolonifera is native to Eurasia and northern North America ( Harvey 2007). In the study zone, this taxon has been collected from the Mexican states of Baja California and Veracruz (Fig. 26C ). Agrostis has also been reported from the southern United States and Mexico City, also from the states of Chiapas, Chihuahua, Coahuila, Hidalgo, Jalisco, México, Michoacán, Nuevo León, Puebla, and Tlaxcala ( Dávila et al. 2018; Sánchez-Ken 2019), but no specimens from these states have been seen. This taxon has been collected on stream edges and open areas of pine forests, between 1800-2100 m a.s.l. (Fig. 27C ). There are more records of this species in the study zone, on databases ( GBIF 2023d), but not all of them have images, and thus we were unable to confirm their identity.

Phenology.

Specimens with spikelets have been collected from June to August (Fig. 28C ).

Commentaries.

Agrostis stolonifera is often confused with A. gigantea (see the note under the description of that species). This is a variable species and several infraspecific taxa have been recognized (e.g., Pohl and Davidse 1994; Rúgolo and Molina 1997). The plants from the study zone fit well in A. stolonifera var. palustris , which is distinguished from the typical variety in the more contracted panicles, up to 3 cm wide, and smaller spikelets of 1.6-2 mm long (vs. more open panicles, up to 6 cm wide, spikelets 2-2.5 mm long in the typical variety). The width of the panicles could be related to the age of the panicles, since they become contracted after anthesis, and thus varieties are not recognized here.

This taxon is also confused with Polypogon viridis (Gouan) Breistr., from which it is distinguished in the spikelets disarticulating above the glumes (vs. disarticulation below the glumes, with a pedicel fragment in P. viridis ).

Conservation status.

Since Agrostis stolonifera is an introduced taxon in the study zone, its conservation status is considered as Least Concern (LC).

Specimens examined.

Mexico. Baja California: Municipio Ensenada, Sierra San Pedro Mártir, La Grulla , [30.88916°N, 115.46223°W], 2100 m alt., 21 Aug 1967, R. Moran and R.F. Thorne 14466 (SD) . Veracruz: Municipio Tatatila, camino Las Vigas-Tatatila , 1 km antes de La Mancuerna, 19.675°N, 97.125°W, 1800 m alt., 7 Jun 1996, H.R. Sandoval and B.V. Hernández 370 (CIB), 380 (CIB, MEXU [*, **], XAL) .

Figures

Figure 4. Florets of Agrostis species observed with SEM A A. bourgaei B A. calderoniae C A. capillaris D A. elliottiana E A. exarata F A. ghiesbreghtii G A. gigantea H A. hyemalis I A. laxissima J A. microphylla K A. pallens L A. perennans M A. scabra N A. stolonifera O A. subpatens P A. subrepens Q A. tolucensis R A. turrialbae S A. variabilis. Scale bars: 0.3 mm.

Figure 26. Map of known geographic distribution of Agrostis species, based on herbarium specimen data A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis.

Figure 27. Elevation histograms of Agrostis species A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis G A. turrialbae H A. variabilis.

Figure 28. Phenology histograms of Agrostis species A A. perennans B A. scabra C A. stolonifera D A. subpatens E A. subrepens F A. tolucensis G A. turrialbae H A. variabilis.

Figure 30. Calluses of Agrostis species observed with SEM A A. scabra B A. stolonifera C A. subpatens D A. subrepens E A. tolucensis F A. turrialbae G A. variabilis. Scale bars: 50 μm.

Figure 31. Leaf blade anatomy in transversal section of Agrostis species, in general view, and details of lateral bundles. A - C A. scabra D - E A. stolonifera F - G A. subpatens H - I A. subrepens. Scale bars: 0.1 mm.

Figure 32. Lemma surface of Agrostis observed with SEM A A. scabra B A. stolonifera C A. subpatens D A. subrepens E A. tolucensis F A. turrialbae G A. variabilis. Scale bars: 15 μm.

Figure 33. Agrostis stolonifera A whole plant B ligular area C spikelet D floret, abaxial view, E floret, lateral view showing the lemma and the palea F palea. Based on Sandoval and Hernandez 380 (CIB). Scale bars: 3 cm (A); 1 mm (B); 0.5 mm (C); 0.3 mm (D, E); 0.2 mm (F).