phyllo-, phyll-, -phyll, -phyllous

Divination with leaves.

An abnormally excessive development of leaves.

The most advanced geochemical stage of diagenesis (process of chemical and physical changes in deposited sediment during its conversion to rock), characterized by the replacement of clays by micas, feldspars, and chlorites.

Diagenesis refers to changes that take place in a sediment as a result of increased temperatures and pressures, causing solid rock to form, e.g. as sand becomes sandstone.

Mica is a group of chemically and physically related aluminum silicate minerals, common in igneous and metamorphic rocks, characteristically splitting into flexible sheets used in insulation and electrical equipment.

Feldspars are any of a group of abundant rock-forming minerals occurring principally in igneous, plutonic, and some metamorphic rocks, and consisting of silicates of aluminum with potassium, sodium, calcium, and, rarely, barium. About 60 percent of the earth's outer crust is composed of feldspar.

Chlorites consist of any of a group of green soft secondary minerals consisting of the hydrated silicates of aluminium, iron, and magnesium in monoclinic crystalline form; common in metamorphic rocks.

1. The succession and variations of leaves during different seasons.
2. The study of the transformations of leaves during different seasons.

Leaf-bearing; producing leaves.

The larva of the spiny lobsters.

Its body is very thin, flat, and transparent; while the legs are very long.

1. The surface of a leaf considered as a habitat; especially, for microorganisms.
2. The three-dimensional micro-environment surrounding a leaf.

The order or geometric principles of arrangement of leaves (or other lateral members; such as, florets of a composite flower, scales of a pine-cone, etc.) upon an axis or stem.

The principal kinds of phyllotaxis are

1. Cyclical or verticillate, in which a number of leaves (two or more) stand at the same level, forming a pair or whorl.
2. Spiral or alternate, in which each leaf stands singly, with its points of insertion forming a spiral (the genetic spiral) around the stem.

In the latter case, the phyllotaxis is expressed by a fraction denoting the angle (or portion of one turn of the spiral) between two successive leaves; thus, in a 25 phyllotaxis, there are five leaves in every two turns of the spiral.

1. The arrangement of the leaves on the stem.

The three common positions are alternate, opposite, and verticillate.

2. The principles governing leaf arrangement.

When spiral, often expressed quantitatively as the fraction of the circumference of the stem that separates two successive leaves.