Achnatherum calamagrostis subsp. calamagrostis

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

Achnatherum calamagrostis subsp. calamagrostis (L.) P. Beauv. ( Figure 50 (1)).

Lemma dorsal surface: Characterised by long rectangular cells of (14–)18–30(–38) × (9–)10–14(–16) µm, undulated to thin, smooth walls up to 3 µm thick, linear distribution. Short cells: main Silica cells (8–)10–18(–22) × (9–)11–19(–22) µm, circular to ovoid, of linear distribution, frequently solitary, occasionally with cork cells, high density 19–28(–32) silica cells/ 100 µm 2; Cork cells fusiform, sub-quadrangular to reniform (4–)5–9 × 9–18(–20) µm, in pairs or threes with silica cells. Spines and hairs: Hooks not studied; Prickles circular to obovate base 16–25(–28) × (12–)15–24(–26) µm and up to 55 µm long, density <1 prickles/ 100 µm 2; Macro-hairs 550–800(–950) µm long, circular to obovate base (10–)12–20(–24) × 11–19(–22) 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 65 µm long. Short cells: Silica cells equal in size, distribution and morphology, but low density 18–24(–27) silica cells/100 µm 2; Cork cells of equal size, distribution, morphology and frequency. Spines and hairs: Hooks circular base 16–19(–21) µm, rare, solitary, density <2 hooks/ 100 µm 2, distributed at distal end of the apex; Prickles equal in morphology and size, denser 3–5 prickles/ 100 µm 2, distributed across lemma apical surface, antrorse (more) and retrorse (fewer); Macro-hairs circular to ovoid base 21–27(–30) × 19–25(–29) µm and up to 160 µm long, located at middle and distal parts of apex.

Awn base surface: Long cells 70–120(–130) × 6–9 µm, extremes rounded, thin, smooth walls up to 3 µm thick, linear distribution. Short cells: Silica cells circular (7–) 9–12(–14) µm, frequently solitary, occasionally in pairs with cork cells in lines; Cork cells quadrangular 5–7(–8) × 8–11 µm, pairing with silica cells. Spines and hairs: Prickles of equal morphology and size to lemma apical surface, antrorse (more) and retrorse (fewer) and of similar density 2–6 prickles/ 100 µm 2, distributed irregularly. Stomata paracytic (Parallel cell wall type) situated between lines of prickles 7–12 µm long, density 1–2 stomata/100 µm 2.

Material studied: Spain: Huesca : Hecho, subida a Peñaforcada, 10-VIII-1990, S . García & F. M . Vázquez , HSS n.n.

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.