| Quercus hinckleyi | |
|---|---|
| Conservation status | |
|
Imperiled (NatureServe) |
|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fagales |
| Family: | Fagaceae |
| Genus: | Quercus |
| Species: | Q. hinckleyi |
| Binomial name | |
| Quercus hinckleyi C.H.Mull. |
|
Quercus hinckleyi is a rare species of oak known by the common name Hinckley oak. It is native to Texas in the United States, where it occurs in only two counties. The oak has probably become rare not because of habitat loss, but because today's climate in its native area is too dry.[1] It is federally listed as a threatened species of the United States.
This oak is a shrub growing into a bushy, tangled thicket not more than 1.5 meters tall. The highly branched stems are coated in scaly gray bark and the smaller twigs are brown and sometimes waxy. The leaves are up to 1.5 centimeters long by 1.5 wide and have large, widely spaced teeth, resembling holly leaves. The blades are leathery, waxy, and blue-green in color. The fruit is an acorn 1 to 1.5 centimeters wide at the cap, the nut measuring up to 2 centimeters long.[2]
This oak is known from Brewster and Presidio Counties in West Texas. It may also be found just across the border in Mexico.[2][3] The plant grows in Chihuahuan Desert scrub habitat on limestone substrates.[1] The tree grows in very rocky soils or sometimes cracks in solid limestone outcrops.[4]
Climate change has been implicated as the main reason for the rarity of this plant. It was more abundant 10,000 years ago when this region of Texas was wetter; there are plentiful fossilized acorns of this species in rodent middens from that era.[1][5] It may have even been a dominant species.[2] Low rates of reproduction may also contribute to its rarity.[5] There are about 10 populations in Texas.[1] Most populations are located in Big Bend Ranch State Park.[1][4]