Achnatherum calamagrostis subsp. mesatlasicum (Quézel) Dobignard, 2010

Vázquez, Francisco Maria, Márquez, Francisco, García, David & Oualidi, Jalal El, 2025, A taxonomic revision of Stipeae s. l. tribe (Poaceae) in N Africa, Phytotaxa 699 (1), pp. 1-174 : 89-90

Achnatherum calamagrostis subsp. mesatlasicum (Quézel) Dobignard ( Figure 50 (2)).

Lemma dorsal surface: Characterised by long rectangular cells of (20–)25–50(–75) × 10–15(–17) µm, undulated to smooth walls up to 3 µm thick, linear distribution. Short cells: main Silica cells (9–)10–22(–24) × (9–)11–20(–24) µm, circular to ovoid, of linear distribution, frequently solitary, occasionally with cork cells at the margin, high density 15–20(–24) silica cells/ 100 µm 2; Cork cells fusiform, sub-quadrangular to reniform (4–)6–10 × 10–20(–22) µm, in pairs with silica cells. Spines and hairs: Hooks not studied; Prickles rare, at the margin, circular to obovate base 19–25 × 14–25 µm and up to 30 µm long, density <1 prickles/ 100 µm 2; Macro-hairs 350–700(–750) µm long, circular to obovate base 18–25(–30) × 16–24(–28) µm, irregularly distributed across entire surface.

Lemma apical surface: Characterised by long cells similar to those of the dorsal area, with undulated to sinuous walls up to 3 µm thick and longer, up to 105 µm long. Short cells: Silica cells equal in size, distribution, and morphology, but low density up to 11–20(–24) silica cells/100 µm 2; Cork cells equal in size, distribution, morphology, and frequency. Spines and hairs: Hooks not studied; Prickles equal in morphology and up to 45µm long, denser 2–5 prickles/ 100µm 2, distributed across lemma apical surface, antrorse; Macro-hairs equal in morphology and up to 160 µm long, distributed across lemma apical surface.

Awn base surface: Long cells 110–160 × 6–9 µm, extremes rounded, thin, smooth walls up to 3 µm thick, linear distribution. Short cells not observed. Spines and hairs: Prickles ovoid to lanceolate base 28–50(–55) × 17–30(–34) µm and up to 60 µm long, of linear distribution. Stomata paracytic (Parallel cell wall type) between lines of prickles 8–14 µm long, density 2–4 stomata/100 µm 2.

Material studied: Morocco: Bon Naceur, valle de Beni Ouriach, VIII-1954, P . Quezel RAB020112 (holotype)

Figures

FIGURE 50. Lemma surface Achnatherum calamagrostis subsp. calamagrostis (1) and Achnatherum calamagrostis subsp. mesatlasicum (2). A. Lemma central dorsal surface view.B. Lemma margin dorsal surface view. C. Lemma apical surface. D.Awn surface. lc: Long cell; sc: Silica cell; cc: Cork cell; h: Hook; p: Prickle; mh: Macro-hair; s: stomata. Bars indicate 100 µm.