Appendix C. Glossary
calibration species — A set of 20 plants selected to help “calibrate” phenological measurements across the USA. These native and introduced plants have broad distributions and are ecologically or economically significant. Observations on calibration species will be integrated to get “the big picture” regarding plant response to environmental change. Widespread observation of calibration species helps integrate collective plant data with climate change measurements nationwide.
canopy — A layer of vegetation elevated above the ground. It can refer to the layer of vegetation that comprises the top layer of a forest or the layer of leaves surrounding an individual tree or shrub
cotyledon — seed leaf; embryonic leaf; the first leaf or one of the first pair of leaves to develop in a seed plant. Cotyledons, when they emerge with seedling shoot, do not look the same as the plant’s “true leaves,” which develop after germination.
larva — The newly hatched, earliest stage of any of various animals that undergo metamorphosis, differing markedly in form and appearance from the adult. Caterpillars are the larval form or larvae (pl) of butterflies and moths.
negative data — The record of not seeing an animal of study or observing that a phenophase is not occurring. Negative data is just as important as sightings of animals observing phenophase occurrence.
Examples include the period over which newly emerging leaves are visible or the period over which open flowers are present on a plant.
pollen — A mass of microspores in a seed plant, usually appearing as a fine dust. Pollen grains are transported (typically by wind, water, insects or animals) from a stamen to a pistil, where fertilization occurs.
seaweeds — although they have many plant-like features, are not true vascular plants; they are algae, part of the Kingdom Protista, which means that they are neither plants nor animals. Seaweeds are not grouped with the true plants because they lack roots, stems, leaves, enclosed reproductive structures like flowers and cones and a specialized vascular system (a conducting system for fluids and nutrients). They are able to take up fluids, nutrients, and gases directly from the water, in which they come in contact and do not need an internal conducting system. Like true plants, seaweeds are photosynthetic, converting energy from sunlight into materials needed for growth. Seaweeds have the green pigment chlorophyll within their cells, which absorbs the sunlight they need for photosynthesis.