Castanea pumila var. ozarkensis
Status Ozark chinquapin is in decline due to chestnut blight, a fungal disease which kills trees before they mature. Previously, the species was a Category 2 (58 FR 188; September 30, 1993), but currently has no Federal status.
Ozark chinquapin grows in small populations of 15 to 25 individuals, generally stump sprouts less than 16 feet (5 m) tall. Stump sprouts grow from larger trees that were killed by chestnut blight. Ozark chinquapin flowers from late May to June. Nuts mature from June to September. Leaves turn yellow in the autumn.
Ozark chinquapin is found in oak-pine and oak-hickory forests on relatively dry, acid soils on ridge tops and upper slopes adjacent to ravines.
Ozark chinquapin is endemic to the Ozark Plateau region of Oklahoma, Arkansas, and Missouri at 500 to 2800 feet (150-850 m). In Oklahoma, populations are scattered in Choctaw, Delaware, Mayes, Adair, Cherokee, Leflore, Latimer, and McCurtain counties.
Ozark chinquapin might be mistaken for chinquapin oak (Q. muhlenbergii). Unlike Ozark chinquapin, chinquapin oak has bluish-green leaves, teeth on the leaves are more rounded, buds are clustered at the apex of the stem, and of course oaks produce non-spiny acorns. Chinquapin oak also occurs on sandy, basic soils. Allegheny chinquapin (C. pumila var. pumila) has smaller leaves (2.4 to 6.3 inches [6-16 cm] long) with shallower teeth (less than 1/10 inch [2.5 mm] long), and smaller involucres (less than 1 inch [2.5 cm] in diameter). Allegheny chinquapin grows in sandy soil and is most common on the Oklahoma Coastal Plain. It is rare in the Ozark Plateau.
Causes of Decline
The main threat to Ozark chinquapin is chestnut blight, a disease caused by the fungus Endothia parasitica. Chestnut blight was originally from east Asia. It appeared in New York City in 1904 and quickly spread throughout North America, decimating the American chestnut (C. dentata) by 1940. The fungus destroys the inner bark and growing tissue of the trunk. New stems sprout from dead stumps and live for several years until reinfected.
Despite ongoing research, no treatment has been found for chestnut blight. Until a treatment has been developed, protection is problematic. At present it appears that maintaining forest stands inhabited by Ozark chinquapin and not cutting or spray individual trees would be sufficient.
Shrubs or small trees with rounded, yellow-green canopies. Mature trees are 25 to 30 feet (7.6-9.1 m) high and have a crown spread of up to 20 feet (6.1 m). Trunks can reach two feet (60 cm) in diameter. Because of the chestnut blight, most plants are stump sprouts that are less than 15 feet (4.6 m) high and only 4- inch diameter (10.2 cm) trunks. Bark is gray-brown to light gray and smooth on young branches, but becoming furrowed into flat ridges or plates. Buds are dark brown, lightly hairy; and solitary at the apex of the twig. Leaves are deciduous, simple, alternate, sharp-coarsely toothed; they are narrowly oblong or elliptic. They are 5 to 8 inches (13-20 cm) long and 1 1/2 to 3 inches (5-8 cm) wide. The single primary vein has many straight parallel lateral veins. Lateral veins terminate in bristles at the tips of the teeth on the leaf margin. Leaf apices are acutely or abruptly angled. The upper surfaces of leaves are yellow-green and hairless. The under surfaces are paler and glabrous (= hairless) to slightly or densely hairy. The hairs are fine and straight or stellate (= starlike). Leaf petioles (= leaf stalks) are approximately 1/4 inch (8-12 mm) long and glabrous. Flowers are small yellowish, foul-smelling, imperfect (= flower has either all stamens or pistils), and without petals. Flowers are densely clustered into a spike known as a catkin. Catkins are 2 to 8 inches (5.1-20.3 mm) long and slender. They develop in the leaf axils near the end of a branch and are semi-erect to spreading. Each catkin will have either exclusively staminate (= male) flowers or staminate flowers with inconspicuous pistillate (= female) flowers near the base. Catkins with pistillate flowers are closest to the tip of the branch. Staminate flowers have 10 to 20 stamens. Female flowers have one pistil and are surrounded by spiny scales. Fruits are spiny, round, and produced in small clusters (= burs). They are 1 1/2 inches (2.5-3.8 cm) in diameter and covered with slender, hairy, 1/2 inch (1.3 cm) long spines. Burs split into two to six segments, releasing a solitary, dull-brown, roundish, edible nut.