Peridictyon O. Seberg, S. Frederiksen & C. Baden
From the Greek peri- (around) and dictyon (a net), alluding to ‘netlike withering of the basal leaf sheaths’.
Sometimes referred to Festucopsis sancta (Janka) Meld.
Habit, vegetative morphology. Perennial; loosely caespitose. Culms (37–)47–80(–110) cm high; unbranched above; 2–3 noded. Culm nodes glabrous. Young shoots intravaginal. Leaves auriculate (the auricles (0.1-)0.3–0.7(-0.8) mm long). Sheath margins joined (the innovation leaves), or free. The basal sheaths disintegrating into a brownish mass of reticulate fibres. Leaf blades linear; narrow; (1–)1.6–2.6(–3.1) mm wide; not setaceous (junciform); rolled; disarticulating from the sheaths (‘with an abscission layer at junction of sheath and blade’); an unfringed membrane; truncate; ‘extremely short’.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence rather few spikeleted ((6-)7–13(-15)); a single spike ((5-)8–14(-17 cm long). Rachides flattened. Inflorescence espatheate. Spikelet-bearing axes persistent (?). Spikelets solitary; not secund; distichous (?); sessile.
Female-fertile spikelets. Spikelets (11–)12–19(–21) mm long; green; compressed laterally, or not noticeably compressed (?); disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus absent. Callus very short.
Glumes two; more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; hairless; glabrous; pointed; awned (the awn apical, 0.5–1.3 mm long); non-carinate; similar (lanceolate, leathery). Lower glume 2–4 nerved. Upper glume 3–6 nerved. Spikelets presumably with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 5–10. Lemmas entire (?); awned. Awns 1; median; apical (?); non-geniculate; much shorter than the body of the lemma (3–9 mm long). Lemmas hairless; glabrous; non-carinate. Palea present; relatively long (equalling to slightly shorter than the lemma); 2-nerved; 2-keeled. Palea keels hairy (ciliate above). Lodicules present; 2; presumably membranous; ciliate. Stamens 3. Anthers 4.2–6(–6.3) mm long. Ovary hairy; without a conspicuous apical appendage. Stigmas 2.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea (to the lemma); medium sized (4.5–5.5 mm long); not grooved; with hairs confined to a terminal tuft. Hilum long-linear. Endosperm containing only simple starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Long-cells similar in shape costally and intercostally (indistinguishable); of similar wall thickness costally and intercostally (thick walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (the sinuosity quite coarse, regular, associated with conspicuous pitting, and pits also conspicuous in the outside walls). Microhairs absent. Stomata absent or very rare. Intercostal short-cells absent or very rare; in cork/silica-cell pairs; silicified. Intercostal silica bodies rounded and crescentic. No macrohairs or prickles seen. Crown cells absent. Costal short-cells predominantly paired. Costal silica bodies present and well developed; rounded and crescentic.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size (broadly round topped). Midrib conspicuous (by the rather pointed abaxial keel, and its larger abaxial girder); with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans (these small-celled, in the furrows). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries, the minor bundles with small adaxial strands and abaxial strands or girders); forming ‘figures’ (the primaries with massive I’s). Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in a continuous abaxial layer (linking the abaxial sclerenchyma of the bundles).
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Mean diploid 2c DNA value unknown, but chromosomes ‘large’.
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 1 species; Greece and Bulgaria. Species of open habitats; glycophytic. Calcareous, stony or rocky slopes.
Holarctic. Tethyan. Mediterranean. European.
References, etc. Morphological/taxonomic: Seberg et al. 1991. Leaf anatomical: this project.
Special comments. Morphological description scarcely adequate - e.g. spikelet orientation unknown. Fruit data wanting.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).