Hickories
Carya glabra
C. glabra (Mill.) Sweet. Pignut Hickory
Pignut hickory is widely distributed,
ranging from southwestern New Hampshire west to eastern Illinois,
south to Louisiana and from there, east to central Florida. Distribution
maps of C. glabra have included the distribution of C. ovalis,
especially in maps prepared by Little (1971) since the reduction
of C. ovalis to synonomy with C. glabra (Little 1969). Distribution
reported here (distribution
map) is based on maps
prepared prior to that reduction (Little 1949), as well as subsequent
reports which continue to distinguish the two taxa. Proponents
of recognizing both species associate C. glabra with sites in
valleys, along streams or less exposed hillsides, while C. ovalis
is more common on dry exposed upland hillsides (Manning 1950).
C. glabra is a minor component of two forest types: Post Oak-Black
Oak; and White Oak-Red Oak-Hickory (Fowells, 1965).
C. glabra is distinguished by its glabrous
leaves, usually with
5 leaflets, its pyriform
fruit with smooth husks
which are only partially dehiscent, and by the tight bark
of mature trees. C. ovalis shares the feature of glabrous leaves,
but usually has 7 leaflets. C.
ovalis has warty husks
which dehisce to the base along sutures which are often somewhat
winged. The bark of mature trees sheds in long thin strips. It
is interesting that the only named cultivar of C. glabra is evidently
wrongly attributed to that species. 'Brackett' was named in 1896, from a specimen received from G.
B. Brackett, Denmark, Iowa (Heiges 1896). The figure of the fruit
(Heiges 1896, Pl. 12, fig. 4, 4a, 4b.) is clearly not C. glabra,
but is evidently C. X laneyi, the hybrid between C. ovata and
C. cordiformis. This determination is based on the presence of
prominent lacunae, which are lacking in both C. glabra and C.
ovata, but are present in C. cordiformis and its hybrids; by the
general appearance of the nut, with the prominent apex characteristic
of C. cordiformis and its hybrids but atypical of C. glabra; by
the dehiscent husks, apparently partially winged as in C. cordiformis,
but atypical of C. glabra; and by the kernel which lacks the convolutions
of C. cordiformis but is consistent with kernels of C. X laneyi.
Heiges (1896) noted that "the kernel is large and full, and
in flavor resembles closely H. ovata, but in color of surface
is more like the bitternut, H. minima" (p 69).
Manning (1950) noted that C. glabra readily hybridized with C.
ovalis when the two occurred together, with hybrids confusing
the distinctions between the species.
LJ Grauke
, Research Horticulturist
& Curator
USDA-ARS Pecan Genetics
10200 FM 50
Somerville, TX 77879
tele: 979-272-1402
fax: 979-272-1401
e-mail: ljg@tamu.edu
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