1. Croton capitatus Michx. (woolly croton, hogwort)
Map 1656, Pl.
377 k–o
Plants monoecious,
densely pubescent with short, stellate hairs, the branches 0.4–1.0 mm long,
often slightly unequal. Stems 20–90 cm long, often sparsely to moderately
alternately branched, but sometimes with a pronounced whorl of branches above
the midpoint. Leaves all or mostly alternate, at least the lower and median
leaves long-petiolate, the petiole without large, saucer-shaped glands at the
tip. Leaf blades 2–12 cm long, lanceolate to oblong-lanceolate,
triangular-lanceolate, or triangular-ovate, rounded or less commonly shallowly
cordate at the base, rounded to angled or tapered to a bluntly or sharply
pointed tip, the margins entire or slightly wavy below the midpoint, the
undersurface usually paler than the upper surface. Inflorescences terminal at the
branch tips (the uppermost branches sometimes short and these inflorescences
then appearing axillary), short, dense, spikelike racemes (often appearing
headlike or as dense clusters) with pistillate flowers toward the base and
staminate flowers toward the tip. Staminate flowers with the calyx deeply
5-lobed, 0.8–1.2 mm long; the petals 5, 0.8–1.2 mm long, white to pale
cream-colored; the stamens (7–)10–14. Pistillate flowers with the calyx 2–4 mm
long at flowering, becoming enlarged to 6–9 mm long at fruiting, 6–9-lobed; the
petals absent; the ovary 3-locular, the 3 styles each dichotomously lobed 2 or
3 times (the total number of stigmatic branches thus theoretically 12–24 per
flower, but in practice mostly 12–16; the second and third order divisions
usually well above the style base). Fruits 6–9 mm in length and diameter,
nearly spherical, persistently densely hairy at maturity, 3-seeded (rarely
2-seeded by abortion of 1 ovule), dehiscent. Seeds 3.5–5.0 mm long, circular to
oblong in outline, sometimes somewhat flattened, the caruncle present. 2n=20.
June–October.
Scattered nearly
throughout the state but apparently absent from the far northwestern portion
(eastern U.S. west to South Dakota and Texas; Mexico). Glades, upland prairies,
and sand prairies; also pastures, dry ditches, old fields, fallow fields,
farmyards, railroads, roadsides, and open, sandy, disturbed areas.
Steyermark
(1963) noted that cattle can become poisoned if they eat hay contaminated with
this species, but that they tend to avoid living plants in pastures because of
the bitter flavor that renders them relatively unpalatable. Burrows and Tyrl
(2001) noted that the diterpenoid esters (croton oils) characteristic of the
genus cause inflammation of the digestive tract.
Steyermark
(1963) treated C. capitatus as comprising two varieties in Missouri. A
third variety recognized by some authors (Johnston, 1958), var. albinoides
(A.M. Ferguson) Shinners, grows in Texas and Mexico and differs only slightly
from var. lindheimeri in its smaller (less than 4 mm long), more
strongly obovate seeds. Johnston (1958) and Webster (1967) suggested, however,
that the two taxa in Missouri might better be treated as distinct species. In
spite of this, a number of seemingly intermediate specimens exist that appear
to justify the use of a lower taxonomic rank. The characters used by Steyermark
are also different than those used by Johnston, which may account for some of
the ambiguously placed specimens, as Steyermarks use of leaf size and
hair color does not appear to separate Missouri materials adequately.