DNA sequence data from the chloroplast gene ndhF were analyzed to estimate the phylogeny of the subfamily Panicoideae, with emphasis on the tribe Paniceae. Our data suggest that the subfamily is divided into three strongly supported clades, corresponding to groups with largely identical base chromosome numbers. Relationships among the three clades are unclear. In unweighted parsimony analyses, the two major clades with x = 10 (Andropogoneae and x = 10 Paniceae) are weakly supported as sister taxa. The third large clade corresponds to x = 9 Paniceae. In analyses under implied weight, the two clades of Paniceae are sisters, making the tribe monophyletic. Neither resolution is strongly supported.Our molecular phylogenies are not congruent with previous classifications of tribes or subtribes. Based on this sample of species, we infer that C(4) photosynthesis has evolved independently several times, although a single origin with multiple reversals and several reacquisitions is only slightly less parsimonious. The phosphoenol pyruvate carboxykinase (PCK) subtype of C(4) photosynthesis has evolved only once, as has the NAD-malic enzyme (ME) subtype; all other origins are NADP-ME. Inflorescence bristles are apparently homologous in the genera Setaria and Pennisetum, contrary to opinions of most previous authors. Some genera, such as Digitaria, Echinochloa, and Homolepis are supported as monophyletic. The large genus Paspalum is shown to be paraphyletic, with Thrasya derived from within it. As expected, Panicum is polyphyletic, with lineages derived from multiple ancestors across the tree. Panicum subg. Panicum is monophyletic. Panicum subg. Dichanthelium, subg. Agrostoides, and subg. Phanopyrum are unrelated to each other, and none is monophyletic. Only Panicum subg. Dichanthelium sect. Dichanthelium, represented by P. sabulorum and P. koolauense, is monophyletic. Panicum subg. Megathyrsus, a monotypic subgenus including only the species P. maximum, is better placed in Urochloa, as suggested by other authors.

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Paspalum, an American genus of the x = 10 Paniceae clade, includes about 330 species, four subgenera, and 27 informal groups. Within the genus, the Quadrifaria and Virgata groups are well-represented in South and Central America. Interspecific variability make the delimitation of these groups difficult; hence several species have been included or excluded from Quadrifaria or Virgata depending on the taxonomic treatment. In previous analyses, the Quadrifaria and Virgata groups of Paspalum were polyphyletic. Here we present a new appraisal of the classification of both groups based on the phylogenetic analyses of DNA data from the chloroplast: the rpl16 intron, and the region comprising the trnL and trnF genes. A monophyletic Virgata clade is recovered, consisting of nearly all the species listed in an unpublished manuscript. The Quadrifaria group is restricted to P. quadrifarium and P. quarinii. Other clades grouped species traditionally treated within Virgata or Quadrifaria, although their phylogenetic placement needs to be reevaluated. Within most of the clades, diploid and polyploid species seemingly derive from a common ancestor denoting an autopolyploid origin. Alloploidy is also possible although reticulate evolution needs to be explored. The wide distribution of the I genome suggests that this is a plesiomorphic state in Paspalum.

Vivipary, the germination of seeds before they are shed from the parent plant, is a rare event in angiosperms involving complex ecophysiological processes. Pseudovivipary and cryptovivipary occur in approximately 30 (2%) species of the cactus family. A remarkable case of vivipary in Epiphyllum phyllanthus is described here. Information is provided regarding the biology of viviparous fruits, morphology, mortality, survival rates of viviparous offspring, and some eco-evolutionary implications of this reproductive strategy in the Cactaceae. This epiphytic cactus has no host-specific relationship. A low proportion (33.3%) of individuals produced viviparous fruits. Seed number/fruit varied from 197 to 230 with percentage of viviparous germination from 97.5% to 99%. The viviparous seedlings exhibited normal development and were no different from non-viviparous offspring. Transplanting experiments showed that the first week is critical for seedling establishment, and high mortality occurred in the three treatments used: 69% on the phorophyte surface, 58.6% on the ground, and 44.8% under controlled conditions. The number of survivors gradually stabilized, and the contribution to establishment was comparable in each of the treatments after the acclimation phase. It is suggested that vivipary is associated with thermoregulation, parental care, conspecific nursing, and rapid seedling establishment. Germination is not a limiting factor in the perpetuation of this viviparous species, but seedling establishment is. In viviparous individuals of E. phyllanthus, seedling mortality during establishment rather than failure to germinate within the fruit is a limiting factor affecting local population density. Overall, viviparity is an intrinsic, genetic event involving high metabolic costs favouring germination and dispersal of the fittest offspring regardless of substrate and environmental conditions.

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The taxonomy, rarity, and conservation status of Allium  L. is revised for the Canadian prairie provinces, based on analyses of herbarium specimens and fieldwork. Five species are recognized: Allium schoenoprasum  L., A. geyeri S. Watson var. tenerum M.E. Jones, A. textile A. Nelson & J.F. Macbride, A. cernuum Roth, and A. stellatum Ker Gawler. Distribution maps and a key to species are provided, as well as complete descriptions of the species examined, including new illustrations, information on nomenclatural types, synonymies, and chromosomal and ecological data. A lectotype is designated for A. geyeri var. tenerum. In this study, A. geyeri var. geyeri reported from Alberta and Saskatchewan and ranked in these provinces as having rarity levels S2 and S1, respectively, by the Nature Conservancy, is excluded from the Canadian flora and the rare list of these provinces because it was misidentified from a herbarium specimen of A. textile. Allium tricoccum Solander in W. Aiton is regarded as a non-native species to Manitoba. The rarity and conservation status of Allium in the Canadian prairie provinces is as follows: (i) A. schoenoprasum, listed as S2 in Saskatchewan, is rare in Manitoba, although its rarity status has not been formally assessed in the province; (ii) A. geyeri var. tenerum is the rarest Allium taxon, with distribution restricted to the Waterton Lakes National Park areas of Alberta, and is currently listed as S2; and (iii) A. cernuum was re-evaluated and a rarity level of S1S2 was recommended for the species in Saskatchewan, particularly in its southwestern distributional habitat.

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