Stipa offneri Breistr., 1950

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 : 112

Stipa offneri Breistr. ( Figure 64 (1)).

Lemma dorsal surface: Characterised by rectangular to quadrangular long cells of (16–)25–50(–61) × 16–21 µm, smooth to undulated walls 7–9 µm thick in smooth walls to 10–14 µm in undulated walls, linear distribution. Short cells: main Silica cells of 10–14 × 18–24 µm, circular to oblong, sporadic in dorsal and frequent at margins, in all cases in pairs or threes with silica, hook and occasionally cork cells, never solitary; Cork cells 7–10 × 18–21 µm, oblong, sporadic, in all cases with silica cells. Spines and hairs: Hooks circular to quadrangular base 12–23 × 7–9(–10) µm high, regularly distributed between long cells, in pairs or threes with silica, cork or additional hook cells, more frequently solitary, density 12–16 hooks/100 µm 2; Prickles not studied; Macro-hairs up to 410 µm long, circular base 19–24 µm, regularly distributed in lines from mid-dorsal area to lemma base.

Lemma apical surface: Characterised by long cells similar to those of the dorsal area, thin walled to 18 µm. Short cells: Silica cells of equal size, morphology and distribution, more frequent (12–15 silica cells/100 µm 2); Cork cells of equal size, morphology, distribution and density to dorsal. Spines and hairs: Hooks circular equal in size, morphology and distribution, denser than in dorsal area (14–18 hooks/100 µm 2); Prickles circular to ovate base 12–22 × 16–24 µm and (12–)14–55(–60) µm long, distributed at middle and upper parts of apex, up to 6 prickles/100 µm 2; Macro-hairs of circular base 12–24 × 110–400 µm long, located at distal part of apex.

Material studied: Morocco: Tanda, VC 0021/4146, 1640 m.s.a.l., 29-V-2014, M. Chambouleyron ( ECWP s.n. (HSSrf 227 (1/2/3))); Boumia, 0273583/ 3617960, 1910 m.s.a.l., 22-V-2014, M. Chambouleyron ( ECWP s.n. (HSSrf 230)) .

Figures

FIGURE 64. Lemma surface Stipa offneri.(1) and Stipa meridionalis (2). A. Lemma central dorsal surface view. B. Lemma margin dorsal surface view. C. Lemma apical surface. lc. Long cell. sc. Silica cell. cc. Cork cell. h. Hook. p. Prickle. mh. Macro-hair. Bars indicate 100 µm.