Three new species of Aporcelaimoides from natural habitats in Vietnam are studied, described and illustrated, including line drawings, LM and/or SEM pictures. Aporcelaimoidesbrevistylum sp. n. is characterized by its body 1.95-2.90 mm long, lip region offset by deep constriction and 17-18 µm broad, ventral side of mural odontostyle 11-14 µm long with aperture occupying 62-71% of its length, neck 663-767 µm long, pharyngeal expansion occupying 58-66% of total neck length, uterus a simple tube 85-182 µm long, pars refringens vaginae absent, V = 55-63, tail short and rounded (34-46 µm, c = 49-76, c' = 0.6-0.8), spicules 67-86 µm long, and one ventromedian supplement out the range of spicules. Aporcelaimoidesminor sp. n. is distinguished in having body 2.09-2.61 mm long, lip region offset by deep constriction and 19-20 µm broad, mural odontostyle 14-16 µm long at its ventral side with aperture occupying 73-84% of its length, neck 579-649 µm long, pharyngeal expansion occupying 57-66% of total neck length, uterus a simple tube 44-69 µm long, pars refringens vaginae well developed, V = 48-56, female tail very short, rounded conoid or truncate (14-26 µm, c = 90-146, c' = 0.3-0.6), and male unknown. Aporcelaimoidessilvaticum sp. n. is characterized by its body 2.09-2.60 mm long, lip region offset by depression and 17-18 µm broad, mural odontostyle 11-12 µm long at its ventral side with aperture occupying 60-66% of its length, neck 597-720 µm long, pharyngeal expansion occupying 58-64% of total neck length, uterus a simple tube 128-243 µm long, pars refringens vaginae well developed, V = 58-60, tail short and rounded (27-37 µm, c = 67-94, c' = 0.6-0.7), spicules 64-75 µm long, and two or three widely spaced ventromedian supplements bearing hiatus. The genus Aporcelaimoides is restored, its diagnosis emended, and three species of Sectonema, namely Sectonemaamazonicum, Sectonemahaguei and Sectonemamoderatum, transferred to it. An updated list of its species, a key to their identification and a tabular compendium with the most important morphometric features are also presented.

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Background and aims Oil-producing flowers related to oil-bee pollination are a major innovation in Neotropical and Mexican Iridaceae. In this study, phylogenetic relationships were investigated among a wide array of New World genera of the tribes Sisyrinchieae, Trimezieae and Tigridieae (Iridaceae: Iridoideae) and the evolution of floral glandular structures, which are predominantly trichomal elaiophores, was examined in relation to the diversification of New World Iridaceae. Methods Phylogenetic analyses based on seven molecular markers obtained from 97 species were conducted to produce the first extensive phylogeny of the New World tribes of subfamily Iridoideae. The resulting phylogenetic hypothesis was used to trace the evolutionary history of glandular structures present in the flowers of numerous species in each tribe. Hypotheses of differential diversification rates among lineages were also investigated using both topological and Binary-State Speciation and Extinction methods. Key results and conclusions Floral glandular structures and especially trichomal elaiophores evolved multiple times independently in the American tribes of Iridoideae. The distribution pattern of species displaying glandular trichomes across the phylogeny reveals lability in the pollination system and suggests that these structures may have played a significant role in the diversification of the Iridoideae on the American continent.

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Background and aims Sisyrinchium (Iridaceae: Iridoideae: Sisyrinchieae) is one of the largest, most widespread and most taxonomically complex genera in Iridaceae, with all species except one native to the American continent. Phylogenetic relationships within the genus were investigated and the evolution of oil-producing structures related to specialized oil-bee pollination examined. Methods Phylogenetic analyses based on eight molecular markers obtained from 101 Sisyrinchium accessions representing 85 species were conducted in the first extensive phylogenetic analysis of the genus. Total evidence analyses confirmed the monophyly of the genus and retrieved nine major clades weakly connected to the subdivisions previously recognized. The resulting phylogenetic hypothesis was used to reconstruct biogeographical patterns, and to trace the evolutionary origin of glandular trichomes present in the flowers of several species. Key results and conclusions Glandular trichomes evolved three times independently in the genus. In two cases, these glandular trichomes are oil-secreting, suggesting that the corresponding flowers might be pollinated by oil-bees. Biogeographical patterns indicate expansions from Central America and the northern Andes to the subandean ranges between Chile and Argentina and to the extended area of the Paraná river basin. The distribution of oil-flower species across the phylogenetic trees suggests that oil-producing trichomes may have played a key role in the diversification of the genus, a hypothesis that requires future testing.

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