Pinus stormiae

Pinus stormiae is a species of pine that mostly grows in the northeast of Mexico in the Sierra Madre Oriental pine–oak forests, but also grows in a few areas of far western Texas. It was only ranked as a species in 2024 and is still considered to be a variety of the Arizona pine in some sources.

Pinus stormiae
Near Galeana, Nuevo León
Conservation status
Vulnerable  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Gymnospermae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Pinaceae
Genus:	Pinus
Subgenus:	P. subg. Pinus
Section:	P. sect. Trifoliae
Subsection:	P. subsect. Ponderosae
Species:	P. stormiae
Binomial name
Pinus stormiae (Martínez) Frankis
Synonyms[2]
Pinus arizonica var. stormiae Pinus arizonica subsp. stormiae Pinus ponderosa var. stormiae

Description

Pinus stormiae is a moderate sized tree reaching a maximum of 35 meters (115 ft) with straight trunk,^[3] but is often smaller at 10–20 m (33–66 ft).^[4] In older trees the trunk can be fairly wide, up to 120 centimeters (3.9 ft).^[3] The bark in young trees is rough and has deep cracks and in older ones it takes the form of scaly plates brown to red-brown in color.^[4] Lower branches are thick and are horizontal to drooping, frequently almost brushing the ground. Higher up in the tree the branches usually have a slight upward bent.^[4] When young the twigs are orange-brown and weather to dark gray-brown.^[3] The tree crowns are usually dense and somewhat round, though when young they will have a more pyramid shaped crown with more widely spaced branches.^[4]

Bark on a larger tree

Its leaves resemble needles and are typically in fascicles or bundles of three, but quite often with four or five.^[4] Compared to other related pines its needles are particularly thick and ridged and are also usually twisted with a curve. They measure 14 to 25 cm long and just 1.4 to 1.8 millimeters thick.^[5] Their edges are very finely toothed.^[6]

The seed bearing cones are large and somewhat egg shaped, 4.5–14 centimeters long, though more often 5–10 cm, and 3.5–8 cm wide when opened.^[5] They are dark brown when mature with small, straight spines on the scales. On the trees they are in groups of two to four and release their seeds in November to December, though they do not fall from the branches for several months.^[6] The seeds are just 5–6 mm long by 3.5–4 mm and a slightly flattened egg shape.^[5]

Taxonomy

Pinus stormiae is classified in the subsection Ponderosae in the section named Trifoliae, part of the genus Pinus in the family Pinaceae.^[7]

Pinus stormiae was scientifically described as a variety of Pinus arizonica in 1945 by the botanist Maximino Martínez.^[2][8] It was described as a variety of Pinus ponderosa in 1990 by John Silba (1961-2015) who then published a description of it as a subspecies of P. arizonica in 2009. In 2024 it was described as a species by Michael P. Frankis, giving it three homotypic synonyms.^[2]

Table of Synonyms

Name	Year	Rank
Pinus arizonica var. stormiae Martínez	1945	variety
Pinus arizonica subsp. stormiae (Martínez) Silba	2009	subspecies
Pinus ponderosa var. stormiae (Martínez) Silba	1990	variety

There is disagreement about its status as a species. It is listed as an accepted species by Plants of the World Online and World Plants,^[2][9] but is listed as an accepted variety of Pinus arizonica by World Flora Online.^[10] Similarly, when it was evaluated in 2013 by the IUCN and in 1994 by NatureServe it was as a variety.^[1][11]

Names

The species name is derived from its description of a variety named in honor of the American journalist Marian Isabel Storm.^[3] In its native Mexican range it is known by the Spanish common name of pino real meaning "royal pine" or as pino blanco meaning "white pine",^[12][4] however both Pinus teocote and Pinus engelmannii are known as pino real and eight species are sometimes known as pino blanco.^[13]

Range and habitat

The majority of the species range is in the Mexican state of Nuevo León, but there is also a significant populations in southern Coahuila.^[5] There are also scattered populations in the north of Coahuila, a small one in the southwestern corner of Tamaulipas, and isolated populations in San Luis Potosí. In the United States it only grows in a few widely separated areas the Trans-Pecos in Texas.^[6] It can be found between elevations of 1,500 and 3,000 meters (4,900 and 9,800 ft).^[5]

It grows in the Sierra Madre Oriental, often on west or southwest facing dry mountainsides.^[6] They often grow together, but also grow with oaks, junipers, and other pine species like Mexican pinyons and smooth-bark Mexican pines.^[3]