We conducted a molecular phylogenetic study of the tribe Stipeae using nine plastid DNA sequences (trnK‐matK, matK, trnH‐psbA, trnL‐F, rps3, ndhF, rpl32‐trnL, rps16‐trnK, rps16 intron), the nuclear ITS DNA regions, and micromorphological characters from the lemma surface. Our large original dataset includes 156 accessions representing 139 species of Stipeae representing all genera currently placed in the tribe. The maximum likelihood and Bayesian analyses of DNA sequences provide strong support for the monophyly of Stipeae; including, in phylogenetic order, Macrochloa as remote sister lineage to all other Stipeae, then a primary stepwise divergence of three deep lineages with a saw‐like (SL) lemma epidermal pattern (a plesiomorphic state). The next split is between a lineage (SL1) which bifurcates into separate Eurasian and American clades, and a lineage of three parts; a small Patis (SL2) clade, as sister to Piptatherum s.str. (SL3), and the achnatheroid clade (AC). The AC exhibits a maize‐like lemma epidermal pattern throughout. AC consists of a core clade of Austral‐Eurasian distribution and a “major American clade” of North and South American distribution. The base chromosome number for Stipeae is somewhat ambiguous but based on our survey it seems most likely to be x = 11 or 12. Our phylogenetic hypothesis supports the recognition of the following genera and groups (listed by region): Eurasia—Achnatherum, “Miliacea group”, “Neotrinia” (monotypic), Orthoraphium (monotypic), Patis (also 1 from North America), Piptatherum s.str., Psammochloa (monotypic), Ptilagrostis, Stipa, “Timouria group”, and Trikeraia; Mediterranean—Ampelodesmos (monotypic), Celtica (monotypic), Macrochloa (monotypic), and “Stipella‐Inaequiglumes group”; Australasia—Anemanthele (monotypic), and Austrostipa; North America (NA)—“Eriocoma group”, Hesperostipa, Oryzopsis (monotypic), Piptatheropsis, “Pseudoeriocoma group”, and “Stillmania” (monotypic); South America—Aciachne, Amelichloa (also NA), Anatherostipa (s.str.), Jarava (polyphyletic), Lorenzochloa, Nassella (also NA), Ortachne, Pappostipa (also NA), and Piptochaetium (also NA). Monophyly of Phaenospermateae including Duthieinae is demonstrated, and its inclusion within or treatment as sister to Stipeae is rejected.

Historically, there has been taxonomic confusion among agrostologists regarding the short–spikeleted Stipeae. We refer to these as the Oryzopsis/Piptatherum complex which consists of short–spikeleted species with coriaceous to cartilaginous and often caducous–awned lemmas, and florets with a blunt callus. We conducted a phylogenetic analysis of 53 species that have been associated with this complex using four plastid regions (ndhF, rpl32–trnL, rps16–trnK, rps16 intron) in combination with lemma micromorphology to infer evolutionary relationships. Piptatherum as currently circumscribed is polyphyletic and is found in five strongly supported clades in our maximum likelihood tree. Based on our phylogenetic and morphological evidence we recognize a Eurasian Piptatherum s.str., propose a new genus, Piptatheropsis, to include five North American species, and resurrect the genus Patis to include three species, two from Eurasia and one from North America. We provide morphological descriptions of Patis, Piptatherum, and Piptatheropsis, and provide keys to the genera and species of the Oryzopsis/Piptatherum complex. The following new combinations are made: Patis obtusa, Patis racemosa, Piptatheropsis canadensis, Piptatheropsis exigua, Piptatheropsis micrantha, Piptatheropsis pungens, Piptatheropsis shoshoneana, Piptatherum brachycladum, and Piptatherum kopetdagense.

G. tenuis M. Bieb.) as regards leaves, seeds and pollens are presented with this investigation in a detailed way. An examination of the surface structure of the leaves, seeds and pollen grains of the Gladiolus species indicates that the characteristics of the ultrastructure of leaves and of pollen grains are not diagnostic for distinguishing species, but they could be important at genus level (leaves: features such as being amphistomatic, having the same quantity of immersed stomata on both surfaces and having a high stomata index, the presence and localisation of papillae, the shape of epidermal cells; pollen grains: monosulcate type with two operculums). However, the type of surface ultrastructure of the seed coat is a diagnostic feature as at genus level so for species. It can be mentioned that propose the use of features such as the shape and position of the cicatricle, the type of cuticle, the shape and boundaries of cells of testa, and the anticlinal cell walls as diagnostic features at genera level. The shape of seeds, the presence and disposition of wing, the level of the periclinal cell walls of the seed coat and types of relief are additional diagnostic features for distinguishing of Gladiolus species.