3. Castanea pumila (L.) Mill. (chinquapin)
Pl. 413 d–g; Map
1837
Plants shrubs or
trees to 20 m tall (mostly much shorter now). Bark gray to brown, smooth to
deeply furrowed. Twigs dark brown or grayish, with inconspicuous, sessile
glands and/or short gland-tipped hairs. Buds with the outer pair of scales dark
purple, glabrous or hairy. Leaves with the petiole 2–19 mm long, with
inconspicuous glands or short glandular hairs, sometimes also variously
longer-hairy. Stipules lanceolate, shed early. Leaf blades 7.5–21.0 cm long,
3–9 cm wide, narrowly elliptic to oblanceolate or narrowly obovate, rounded,
broadly angled, or rarely narrowly angled at the base, broadly to sharply
angled or short-tapered at the tip, the marginal teeth 1–9 mm long, broadly to
slenderly tapered or short-tapered above a triangular base, straight or curved,
the secondary veins 11–23 on each side of the midvein, both surfaces with the
main veins with inconspicuous glands or short glandular hairs, the undersurface
also sparsely to densely hairy between the veins. Cupules 2–13 per spike, 1–2
cm wide at fruiting (excluding the spines), splitting into 2 valves, the spines
5–13 mm long. Nut 1 per cupule, 7–20 mm long, more or less circular in
cross-section. 2n=24. May–June.
Uncommon in
southernmost Missouri (eastern U.S. west to Missouri and Texas). Mesic to dry
upland forests; fencerows and roadsides; often on acidic substrates.
This species is
less susceptible to chestnut blight than is C. dentata. The blight
develops more slowly, and infected stems live much longer before dying, so they
are able to set seed. The characteristic growth form of the species has
changed, however; due to the repeated death and replacement of the trunks. The
tall, single-trunked trees present before the blight have been replaced by low,
multitrunked small trees or shrubs. Large chestnut logs can still be found
associated with living colonies of smaller trees in some parts of the Ozarks.
Castanea
pumila is a puzzling and
problematic species that has been split into six or more species by some
authors (G. P. Johnson, 1988). In the Ozarks, there are two taxa that are
generally well defined, which are treated as varieties in the present work.
This is primarily because other races elsewhere in the range of the species
intergrade with the Ozark race of var. pumila, and some of these combine
characters of the Ozark race of var. pumila with characters of var. ozarkensis
(larger, more tapered leaves, larger cupules, and sparser pubescence). As noted
under var. pumila, the key and descriptions below hold only for Ozark
material. In the literature, our two varieties are said to differ in twig
indumentum (pubescent in var. pumila, glabrous in var. ozarkensis),
but this character does not hold up in Missouri and Arkansas populations.