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The Fossil Record Of Basal Monocots, Ruth A. Stockey
The Fossil Record Of Basal Monocots, Ruth A. Stockey
Aliso: A Journal of Systematic and Floristic Botany
The fossil record of basal monocots (Acorales and Alismatales) extends back to the Cretaceous in the Northern Hemisphere. While many fossils were originally assigned to these basal groups, rigorous paleobotanical studies show many of them to be misidentified. Acarus fossils have been reliably reported from the Eocene while those of Alismatales extend back to the early Cretaceous. The fossil record of basal monocots is usually represented by leaves, fruits, and seeds; however, some localities preserve stems with attached leaves and roots and even whole plants. A detailed examination of leaf venation patterns in alismatids has recently allowed the description of …
Speciation In Duckweeds (Lemnaceae): Phylogenetic And Ecological Inferences, Daniel J. Crawford, Elias Landolt, Donald H. Les, Rebecca T. Kimball
Speciation In Duckweeds (Lemnaceae): Phylogenetic And Ecological Inferences, Daniel J. Crawford, Elias Landolt, Donald H. Les, Rebecca T. Kimball
Aliso: A Journal of Systematic and Floristic Botany
Species of duckweeds (Letnnaceae) that were resolved as sister taxa in a phylogeny based on combined molecular and non-molecular data were compared for morphological, physiological, and ecological attributes to infer factors important in the initial divergence leading to speciation. The ability to survive extreme conditions such as desiccation and cold temperatures is the most common difference identified between species. Two morphological characters facilitating survival in extreme environments are production of special resting buds called turions and increased seed production. The prevalent geographic pattern for species pairs consists of one restricted species occurring on the periphery of a more widespread taxon; …
Pollen Wall Ultrastructure Of Araceae And Lemnaceae In Relation To Molecular Classifications, Michael Hesse
Pollen Wall Ultrastructure Of Araceae And Lemnaceae In Relation To Molecular Classifications, Michael Hesse
Aliso: A Journal of Systematic and Floristic Botany
A comparative ultrastructural study of Araceae pollen walls was conducted for the first time. The results are based mainly on investigations by transmission electron microscopy of 101 species in 70 genera (out of a total of 105 genera), while pollen of 83 genera with 219 species were studied by scanning electron microscopy, generally without acetolysis. Special attention was given to Lemnaceae (including Limnobiophyllum) considered to be closely related to Araceae (especially to Pistia). The ultrastructural pollen wall characters are mostly in accordance with and strongly support the morphological classifications and the arrangement of genera within recent molecular trees. …