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Friday, 23 January 2026, 4:07 PM
Site: MISIN Learn
Course: MISIN Learn (MISIN Learn)
Glossary: Glossary
P

Phyllary

An involucral bract of flowers in the family Asteraceae.

Pinnate

Arranged in two rows along an axil, like barbs on a feather.

Pistil

The female organ of the flower, composed of an ovary, style and stigma.

Pith

The central tissue in a stem or root, surrounded by vascular tissue.

Plumbaginaceae

Leadwort 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.

Polemoniaceae

Phlox 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.

Polygonaceae

Smartweed 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.

Pontederiaceae

Pickerelweed or Water Hyacinth Family. Comprised of 2 genera and about 40 species of mostly perennial, aquatic plants. Members of this family have creeping rootstocks, fibrous roots and leaves in clusters at the base of the plant or borne on branched stems.

Potamogetonaceae

Pondweed Family. Comprised of 6 genera and about 110 species of aquatic, monocotyledonous flowering plants. Members of this family develop submerged or floating leaves but frequently have emergent flowering shoots.