Stipa × alba F.M. Vázquez & S. Ramos, 2007

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 : 103

Stipa × alba F.M. Vázquez & S. Ramos ( Figure 58 (1)).

Lemma dorsal surface: Characterised by long rectangular cells of (19–)22–55(–62) × (8–) 10–18(–21) µm, sinuous walls up to 10 µm thick, linear distribution. Short cells: Silica cells of 8–12 × 5–11 µm, circular, obovate to oblong, in pairs or threes with hook, or less frequently, cork cells, situated between long cells, never solitary; Cork cells (2–)3–9(– 11) × 7–10 µm, reniform to oblong, sporadic, always with a silica cell. Spines and hairs: Hooks rectangular to circular base (8–)10–19(–21) × 4–7(–8) µm high, regularly distributed between long cells, in pairs or threes with silica, cork or additional hook cells, more frequently solitary, density 12–15 hooks/ 100 µm 2; Macro-hairs 400–550(–740) µm long, circular base 8–21(–24) µm, regularly distributed in rows from mid-dorsal to base of lemma.

Lemma apical surface: Characterised by long cells similar to those of the dorsal area, slightly longer, up to 70 µm and up to 14 µm thick. Short cells: Silica cells of 6–12 × 8–11 µm, more frequent, similar in distribution and morphology to the dorsal; Cork cells (2–)3–7(–9) × 7–10 µm, oblong to reniform, equal distribution to the dorsal. Spines and hairs: Hooks circular base 10–19(–22) µm, denser than at the dorsal area 18–22 hooks/100 µm 2; Prickles circular base 22–35 µm and up to 140 µm long, distributed at middle of apex; Macro-hairs of obovate to circular base (15–)21–32 × 10–14(–18) µm and up to 340 µm long, located at middle and distal parts of apex.

Material studied: Tunisia: Beni M’Hira , near to Tataouïne, 10°49′W, 32°57′N, IV-1996, M . Visser (Holotype – HSS 11867 ) .

Figures

FIGURE 58. Lemma surface of Stipa × alba (1) and Stipa balansae (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.