Fascicle sheaths of the needle bundles shed after the first year, absent in second year needle bundles and older.

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Fascicle sheaths of needle bundles not shed after the first year, retained (in part) in two year old and older needle bundles

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EXPLANATION OF THIS CHARACTER

The needle bundles of new pine growth arise from a woody base and are wrapped at the base by a membranous sheath. After the first year this fascicle sheath may be shed or retained in different groups of pines. If the sheath is shed (top figure above) (Soft Pines), the needles in a bundle arise directly from this woody base in second year and older needle bundles. If the sheath is not completely shed (bottom figure above) (Hard Pines), part of the sheath remains and wraps around the base of the needle bundle like the collar on a turtle neck sweater. You may need a magnifying glass to see this character. Remove a needle bundle from the twig making sure that it is not new growth but at least one year old. Spread the needles apart and look down at the base. If the sheath has not been shed you should clearly see a collar about the bases of the needles. If the sheath has been shed you should see the needles arising separately from a woody base.

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Cones borne on a long stalk, elongate and pointed; high elevations (5000 to 7000 feet) in southern Arizona and southern New Mexico, associated with Ponderosa Pine and Apache Pine.

Chihuahua Pine (Pinus leiophylla)

Cones not borne on a long stalk, ovate to globular; habitat generally at lower elevations (below 5000 feet) and commonly in association with various species of Junipers.

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Needle bundles containg a single needle (rarely 2)

Single Leaf Pinyon (Pinus monophylla)

Needle bundles containing 2 or 3 needles

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Needle bundles containing 4 needles

Parry Pinyon (Pinus quadrifolia)

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Needle bundles usually containing 2 needles (rarely 3 or 1); widely distributed but not found in extreme southern Arizona, extreme southwestern New Mexico, southwestern Texas, or Mexico (Compare the distribution maps in the species accounts).

Two Needle Pinyon (Pinus edulis)

Needle bundles usually containing 3 needles (rarely 2); distribution in extreme southern Arizona, extreme southwestern New Mexico, southwestern Texas, and Mexico (Compare the distribution maps in the species accounts).

Mexican Pinyon (Pinus cembroides)

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