Abies durangensis

Martínez 1942

Common names

Abete de Durango [Spanish], Durango fir; the variety, abete de Coahuila or Coahuila fir.

Taxonomic notes

Syn: Abies neodurangensis Debreczy, Racz et Salazar 1995.

One variety, Abies durangensis var. coahuilensis (I.M. Johnst.) Mart. 1963 (syn. A. coahuilensis I.M. Johnst. 1943) (Farjon 1998).

Description

Trees to 40 m tall and 150 cm dbh, with a straight, round trunk bearing long, horizontally spreading first-order branches that form a narrowly conical to rounded irregular crown. Bark smooth, grey or red-brown on young trees, darkening to black-brown and becoming deeply longitudinally fissured with age. Branchlets purple-red to red-brown, prominently ridged and grooved, smooth to finely pubescent in the grooves; leaf scars circular to ovate. Buds oblong-ovoid, 4-5 mm long, resinous with pink-yellow resin. Leaves spreading on either side of shoot, (14-)20-35(-45) mm long by 1-1.6 mm wide, grooved and bright green above, keeled and glaucous below, stomata in groove on upper surface and numerous on lower surface, 2 white bands with 10 lines; apex rounded or obtuse; resin canals 2, marginal. Pollen cones lateral in leaf axils, 1-2 cm long; microsporophylls red. Seed cones lateral, erect on very short peduncles, subcylindric with obtuse apex, pale yellow to medium brown, 5-10 cm long by 3-4.5 cm wide, scales oblong-transverse, 15-20 × 20-28 mm (i.e. wider than long), hidden bracts about 1/2 height of scale or more. Seeds resinous with a yellow nut, up to 8 mm long with orange-yellow wings 7-10 mm long (Silba 1986, Rushforth 1987, Farjon 1990).

The variety coahuilensis is described as a tree 20-30 m tall, to 30 cm dbh, with habit resembling a Douglas-fir. Bark thick, rugose, black, smoother and paler on upper parts of tree. Branchlets olive-green, turning brown, densely pubescent. Bud globose, slightly resinous, with a ring of free scales at its base. Leaves nearly 2-ranked, (10-)25-35 mm long by 1.7 mm wide, shiny green, hypoderm thicker than in the type variety, fibrovascular bundle continuous, stomata scarce on upper surface, in two bands below; apex pointed or obtuse. Female cone ovoid, apex pointed with a slight nipple, brown, to 10 cm long by 4 cm wide; scales obovate-cuneate, pubescent, erose-denticulate on their margins; bracts hidden, about 2/3 the size of the scale. Seed with a 6-8 mm long nut and wing to 10 mm long (Silba 1986, Rushforth 1987). It differs from the type in its more densely pubescent shoots, shorter leaves, and small number of stomata on the upper side of the leaves (Farjon 1990).

Distribution and Ecology

The typical variety is found in Mexico: Durango, Chihuahua, Jalisco, Nayarit, and Sinaloa at (1600-) 2000-2900 m altitude, usually on well drained talus or lithosols. The climate is moist and cool. It may be found with Pseudotsuga menziesii subsp. glauca, Picea chihuahuana (only near El Salto, Durango), Pinus strobiformis, P. leiophylla subsp. chihuahuana, P. durangensis, Hesperocyparis lusitanica, and Juniperus deppeana (Farjon 1990). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).

The variety coahuilensis is found in Coahuila and Nuevo León, to 2270 m altitude; it is uncommon on damp canyon floor sites (Rushforth 1987) in dense forest with Pseudotsuga menziesii subsp. glauca, Pinus strobiformis, and Hesperocyparis lusitanica (Farjon 1990).

Remarkable Specimens

A tree-ring chronology covering the period 1906-2014 (108 years; crossdated after 1914) was collected in Durango by M. Pompa-García, R. Sánchez-Salguero, and J. J. Camarero (doi.org/10.25921/znwg-st34). Only one such collection of this species is recorded and substantially older trees may occur.

Ethnobotany

Observations

It can be seen from the Mazatlan-Durango Highway only in one place, in a canyon at km. 160-163 (Vladimir Dinets e-mail 2003.12.16). I verified this in February 2007. It is an incredible road, and provides chances to see many different species of Pinus and Juniperus (including Pinus durangensis and Juniperus durangensis). There are several mature trees at this site, but an unfortunate lack of seedlings or saplings.

Remarks

Like most firs of western North America, Abies durangensis is a host of the dwarf mistletoe Arceuthobium abietinum f. sp. concoloris (Hawksworth and Wiens 1996). As an aside, Hawksworth and Wiens (1996) contains a memorial to Frank Hawksworth, who died in 1993, in which it states that he and Wiens, in 1963, once discovered five new species of Arceuthobium in a single day while exploring between Durango and El Salto. That would be quite a day for any botanist. Remembering that adventure, they quote Lucy Bishop Millington, pioneering botanist of the Adirondacks: "There is one day of my life marked with a white stone ... so few such days fall to the lot of man, that we do well to remember them. I drew nearer the secret heart of nature than ever before. I saw what human eyes had not seen before; I touched what none had touched before me. Though all the world may now look on, mine was the first delightful thrill of recognition ... in all one's lifetime scarce such a thing may happen again."

Citations

Encyclopedia of Life. 2009. Abies durangensis Martínez. www.eol.org/pages/1061717, accessed 2009.06.10.

Farjon, Aljos. 1990. Pinaceae: drawings and descriptions of the genera Abies, Cedrus, Pseudolarix, Keteleeria, Nothotsuga, Tsuga, Cathaya, Pseudotsuga, Larix and Picea. Königstein: Koeltz Scientific Books.
- Provides a detailed account, with illustrations.

See also

Liu (1971).