''Picea martinezii'', the Martinez spruce, is a medium-sized

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

growing to 25–35 m tall, and with a trunk diameter of up to 1 m. It is native to northeast

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, where it occurs at two localities in the Sierra Madre Oriental mountains in Nuevo León. It grows at moderate altitudes from 2150–2600 m, growing along streamsides in mountain valleys, where moisture levels in the soil are greater than the otherwise low rainfall in the area would suggest. The bark is thin and scaly, flaking off in small circular plates 5–10 cm across. The crown is conic, with widely spaced branches with drooping branchlets. The shoots are stout, pale buff-brown, glabrous, and with prominent pulvini. The leaves are needle-like, 23–35 mm long, stout, moderately flattened in cross-section, bright glossy green with inconspicuous lines of stomata; the tip is viciously sharp. The

cones A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines conn ...

are pendulous, broad cylindrical, 8–16 cm long and 3 cm broad when closed, opening to 6 cm broad. They have stiff, smoothly rounded scales 2-2.5 cm broad, and are green, maturing pale brown 6–8 months after pollination. The

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s are black, 4 mm long, with a 12–16 mm long pale brown wing. Martinez spruce was only discovered in 1981, and is critically endangered with just two small populations, comprising a few hundred trees and a dozen trees respectively. Fossil evidence shows it had a wider distribution in the past, south to central Mexico. It is related to Chihuahua spruce from northwest Mexico, but differs in the longer, green leaves, and the larger, broader cones with larger scales. No other related spruces are found in North America, with its next-closest relatives in eastern

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. It is a very attractive tree and is starting to be planted as an ornamental tree in botanical gardens, particularly valued in warm areas as it is one of the most heat-tolerant of all spruces. It is named after the Mexican botanist Maximino Martínez.

References

External links

Gymnosperm DatabasePhoto of tree
{{Taxonbar, from=Q3731407 martinezii Trees of Nuevo León Critically endangered plants Flora of the Sierra Madre Oriental