PetioleThe stalk portion of a leaf. |
PetromyzontidaeNorthern Lamprey Family. Comprised of 8 genera and about 43 species. Characterized by their elongate, cylindrical shape, no jaw and a disk-shaped mouth. Nonparasitic species live exclusively in freshwater, while parasitic species live in both fresh and marine environments. |
PhyllaryAn involucral bract of flowers in the family Asteraceae. |
PinnateArranged in two rows along an axil, like barbs on a feather. |
PistilThe female organ of the flower, composed of an ovary, style and stigma. |
PithThe central tissue in a stem or root, surrounded by vascular tissue. |
PlumbaginaceaeLeadwort Family. Comprised of 10 genera and about 560 species. They are primarily annual or perennial herbs, shrubs and climbers. Members of this family usually have a calyx with five joined sepals, flowers in dense clusters, flowers with five petals, and a superior ovary containing one seed. |
Poaceae(formerly Gramineae) Grass Family. Comprised of about 800 genera and 12,000 species. It is the world's single most important source of food and rank among the top five families of flowering plants in terms of species numbers. They account for 24% of the Earth's vegetation. |
PolemoniaceaePhlox Family. Comprised of 18 genera and about 385 species. They are annual or perennial, mostly herbaceous plants but some are woody. Members of this family usually have five joined petals, five stamens, a calyx made of five parts joined into a tube, alternate or opposite leaves, a seed pod with three chambers forming inside the flower and sticky seeds. |
PolygonaceaeSmartweed or Buckwheat Family. Comprised of 48 genera and about 1,200 species. Most are perennial, herbaceous plants with swollen nodes but trees, shrubs and vines are also present. Leaves are simple and arranged alternately on the stems. |