Glossary

Category: P

  • Phylogeny, phylogenetic classification

    Type of classification based on evolutionary relationships, as deduced, for example, from morphological, chemical and DNA characters. The actual and ultimately unknowable evolutionary history of a group that includes, among many things, derivation, time and amount and type of change over time; it is not the output of a computer algorithm, which is merely an…

  • Phylogenetic tree

    (In cladistics) the 2-dimensional grouping of taxa according to assumed common ancestries.  

  • Phylogenetic

    Relating to ancestral history. Pertaining to the development of the species. Contrast with ontogenetic. The study of evolutionary relationships among groups of organisms. Concerning the development of a race or phylum.  

  • Phyllotaxy

    Arrangement of leaves on a stem or branch. Arrangement of leaves on stem.  

  • Phyllopodium

    (In ferns) small outgrowth of rhizome to which the leaf is attached, the portion of the stipe that remains attached to the rhizome.  

  • Phyllopodic

    With blade-bearing leaves only at the base of the plant.  

  • Phyllomorph

    (In Gesneriaceae) a leaf blade and its petiole, but the petiole with more elaborate morphology including the ability to produce other phyllomorphs or inflorescences; phyllomorphs are capable of growth over more than one season and may lose their distal end but keep growing at the base.  

  • Phyllodic leaf base

    Petiole that takes on the functions of a leaf, being flattened and leaf-like.  

  • Phyllode

    Phyllode

    A laterally flattened photosynthetic blade; for example, in many Australian Acacia, the expanded petiole, with the rachis and pinnae (of an otherwise bipinnate leaf) undeveloped or underdeveloped or falling early. A leaflike petiole of a bladeless leaf, as in some Acacia. A petiole that develops into a flattened expansion taking the place of a leaf.…

  • Phylloclade

    Phylloclade

    Portion of stem or branch (several nodes and internodes) flattened and expanded to serve the functions of a leaf. A photosynthetic portion of a stem that is flattened and expanded to serve the function of a leaf. Leaf-stalks that are flattened and resemble leaves.