G

galea— The helmetlike upper lip in certain two-lipped corollas, such as Castilleja sp. (Indian Paintbrush). (See Fig. 6.1.)

garnet— A complex group of minerals (e.g., almandine, andradite, grossular, pyrope) commonly present in metamorphic rocks.

garrulous— Noisy and active behavior that characterizes flocks of some birds.

gelifluction lobe— A tonguelike mass of debris, usually associated with periglacial conditions, where soil saturation occurs because frozen ground prevents the downward percolation of water. The melting of ice and snow saturates the surface zone, and soil flowage results.

geologic time scale— An arbitrary or relative chronologic arrangement of geologic events, commonly presented in chart form with the oldest event and time unit at the bottom and the youngest at the top.

geosyncline— A mobile downwarping of the crust of Earth.

glabrous— No hairs present at all; also used for smooth .

glacial till— Dominantly unsorted and unstratified drift, deposited directly by and underneath a glacier without reworking by meltwater.

glandular— Secreting sticky fluid; bearing glands, commonly on hairs.

glandular-hairy— A surface bearing both glands and hairs, the hairs commonly tipped with glandular secretion.

glaucous— Covered with a whitish or bluish waxy covering; loosely applied to any whitish surface.

gleaning— Picking from the surface of a plant or object.

glochids— A barbed hair or bristle, such as the minute bristles of Beavertail Cactus (Opuntia sp.).

glomerules— A dense cluster of flowers, usually small.

gonad cycle— The annual cycle of activity and inactivity of bird reproduction.

granite— 1. A plutonic or deep-seated rock in which quartz makes up 10 to 50% of the felsic (igneous rock having abundant light-colored minerals in its mode) components, and the alkali feldspar/total feldspar ratio is 65 to 90%. 2. Broadly applied, any holocrystalline quartz-bearing plutonic rock.

granitic soils/substrate— Soil derived from granitic rocks.

granodiorite— A group of coarse-grained plutonic rocks intermediate in composition between quartz diorite and quartz monzonite, containing quartz, oligocase or an-

desine, and potassium feldspar, with biotite and hornblende. It is the approximate equivalent of the intrusive rock rhyodacite.

graupel— Snow pellets, a form of frozen precipitation.

greenschist facies— A set of physical conditions attending the production of metamorphic rocks rich in the minerals albite, epidote, chlorite, and tremolite-actinolite (and rarely biotite).

grubs— Soft, thick, wormlike larvae of certain insects.