Oloptum miliaceum

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 : 96

Oloptum miliaceum (L.) Röser & Hamasha ( Figure 54 (1)).

Lemma dorsal surface: Characterised by rectangular long cells of (25–)37–90(–105) × 8–10(–12) µm, thin, smooth walls up to 1 µm thick, linear distribution. Short cells: main Silica cells (9–)10–14 µm, circular, occasionally elongate 12–18(–20) × 10–14 µm, frequent, occasionally in pairs with cork cells, situated between long cells, frequently solitary, density 25–32(–38) silica cells/100 µm 2; Cork cells (2–)3–7 × 10–12 µm, reniform, sporadic, always with a silica cell. Spines and hairs: Hooks not studied; Prickles not studied; Macro-hairs not studied.

Lemma apical surface: Characterised by long cells similar to those of the dorsal area, no significant differences. Short cells: Silica cells equal in size, morphology, distribution, and density; Cork cells equal in size, morphology and distribution to those in dorsal area. Spines and hairs: Hooks occasionally with circular base 18 µm, distributed in middle of distal apex, solitary; Prickles or Hairs (Macro-hairs) not studied.

Awn base surface: Long cells (22–)42–74(–92) × (6–)7–9(–11) µm, extremes rounded to acute, smooth walls up to 1 µm thick, linear distribution. Short cells absent. Spines and hairs: Prickles of two types: Short Prickles of ovoid to circular base 18–24(–25) × 14–19(–20) µm and up to 50 µm long; Long Prickles to ovoid base 26–40(–45) × 18–26(–30) µm and up to 64 µm long, distributed helicoidally. Stomata paracytic (Parallel wall cells type) between lines of prickles 16–20 µm long, density 2–6 stomata/100 µm 2.

Material studied: Morocco: Maatarka, 1420 m.a.s.l., 6-V-2015, M . Chamboleyron , ECWP n.n.; Tata Tagmoure , 1080 m.a.s.l., 4-IV-2013, M . Chamboleyron , ECWP n.n.

Figures

FIGURE 54. Lemma surface Oloptum miliaceum. (1). Oloptum thomasii (2). A. Lemma central dorsal surface view. B. Lemma apex dorsal surface view. C. Lemma apex and awn insertion. D. Awn surface. lc. Long cell. sc. Silica cell. cc. Cork cell. p. Prickle. s. stomata. Bars indicate 100 µm.