Keyed Out #028 — Alnus rubra

Question 1

Long before any leaf unfolds, the same bare tree hangs out both slim, dangling pollen {catkins} and separate little upright female spikes, dusting itself with wind-borne pollen.

Accepted Answer

birch family

Question 2

Each ripe seed is a minute, dry, one-seeded nutlet rimmed with a thin papery wing and shed by the hundred, not a single heavy nut you could crack in your hand.

Accepted Answer

Betulaceae

Question 3

Its pollinated female spikes ripen into small, hard, woody cone-like {strobiles} that neither soften nor break apart, riding the bare twigs right through winter and beyond.

Accepted Answer

Alnus

Question 4

Dig at its base and the roots carry clusters of firm, coral-like {nodules} where symbiotic Frankia bacteria draw nitrogen straight from the air, letting it thrive on raw, starved ground.

Accepted Answer

Alnus

Question 5

Turn a broad, blunt-tipped leaf over: its whole margin is rolled tightly under ({revolute}) above a rusty, downy underside, the edge finely double-toothed.

Accepted Answer

Alnus rubra

Question 6

It grows into a tall, straight forest tree of 80 to 100 feet (24 to 30 m), its smooth pale grey bark flushing rusty orange within minutes wherever it is scraped or cut.

Accepted Answer

Alnus rubra