As I walk through the desert and mountain landscapes of this Chihuahuan region of Arizona I try to make sense of the profusion of tree and plant species new to me. Compared to the lowland vegetation of the Mississippi valley the plants here might as well be on a planet in another star system.
I’ve been puzzling over the differences between two genuses of trees and shrubs in the Ericacae family, the Heaths. Manzanitas, in the genus Arctostaphylos, are very common around here, while the single local species of Madrone, Arbutus arizonica, is quite rare.
I wanted a quick rule of thumb for distinguishing madrones from manzanitas. The trunk bark is one clue, as madrones have rough oak-like bark while manzanitas have trunks with the same orange-brown bark exhibited on the branches of both manzanitas and madrones.
This evening I came up with a mnemonic which I think will be a help. The leaves of the madrones grow in opposite pairs; the name “madrone” has an “o” in it, which stands for “opposite”.
The leaves of manzanitas grow alternately along the branches, first one leaf growing from one side of a branch, then another growing from the opposite side, but a bit farther along. The name “manzanita” has three “a”s in it, any of which could stand for “alternate”.
A few photos (not mine); the first two are of details of the madrone tree. An English translation of the Spanish word “madrone” is “strawberry”; the name comes from the resemblance of the madrone’s fruit to a strawberry. The other photo shows how the bark of the main trunk becomes gray and blocky, hiding the characteristic brownish-red tones the madrone shares with the manzanita.
Two photos of a manzanita tree:
Soon I’ll be able to distinguish the two similar genera with unerring accuracy!