Lecture Notes Flashcards: Biodiversity, Dichotomous Key, and Tree Identification

Flashcards cover key concepts from the lecture notes: dichotomous keys, leaf morphology and classification, plant reproductive strategies, field identification procedures, and fossil biodiversity context.

What is a dichotomous key?

A tool used to identify a species by a sequence of two-choice decisions at each step, narrowing possibilities until a single species is identified.

What is a fascicle in conifers?

A bundle of needles.

What is the central axis of a compound leaf called?

The rachis.

What is a petiole?

The stalk that attaches a leaf blade to the stem.

What is a leaf leaflet?

A single leaf segment attached to the leaf’s rachis in a compound leaf.

What is the difference between gymnosperms and angiosperms regarding seeds?

Gymnosperms have naked seeds not enclosed in fruit; angiosperms have seeds enclosed in fruits.

What is leaf arrangement when leaves are arranged alternately along the stem?

Alternate.

What is leaf arrangement when leaves are paired opposite each other at each node?

Opposite.

What is leaf arrangement when three or more leaves occur at a single node?

Whorled.

What leaf margin has rounded teeth?

Crenate.

What leaf margin has fine, sharp teeth resembling a saw?

Serrate.

What leaf margin has large, triangular teeth?

Dentate.

What are common leaf lobe shapes described in the notes?

Acute (sharp), rounded, and intermediate.

What is venation in leaves, and what does netted venation mean?

Venation is the pattern of veins; netted venation forms a branching network, unlike parallel venation found in grasses.

What does bristle-tipped mean in leaves?

A leaf tip with a pointed projection or hair-like bristle.

What is humescence in leaf surfaces?

The presence of tiny hairs on the underside of leaves, giving a fuzzy appearance.

What is a leaf scar?

A mark on a stem where a leaf petiole attached and later fell off.