2. Croton glandulosus L. var. septentrionalis Müll. Arg. (sand croton, tropic croton)
Map 1657, Pl.
monoecious, densely pubescent with short, mostly stellate hairs (the upper
surface of the leaves sometimes with some of the hairs appearing unbranched or
nearly so and spreading), the branches mostly 0.3–0.7 mm long and
loosely appressed, but with 1 branch much longer (to 2 mm) and spreading. Stems
15–60 cm long, alternately branched but with some or most of the
branches in irregular whorls. Leaves alternate, opposite, or whorled, short-petiolate,
the petiole with 1 or 2 large, saucer-shaped (or 2-lipped), white to
cream-colored glands at the tip. Leaf blades 1–7 cm long, narrowly
oblong to oblong-lanceolate, oblong-oblanceolate, or less commonly
oblong-ovate, mostly angled or tapered at the base at the base, mostly angled
to a bluntly pointed tip (occasionally rounded or sharply pointed) tip, the
margins finely toothed, the undersurface sometimes slightly paler than the
upper surface. Inflorescences appearing terminal and between the stem branches,
short, dense, spikelike racemes (often appearing as dense clusters) with
pistillate flowers toward the base and staminate flowers toward the tip.
Staminate flowers with the calyx deeply (4)5-lobed, 0.7–1.5 mm long;
the petals (4)5, 1–2 mm long, white; the stamens 7–13.
Pistillate flowers with the calyx 1.2–1.8 mm long at flowering,
becoming enlarged to 3.5–4.5 mm long at fruiting, 5-lobed; the petals
absent; the ovary 3-locular, the 3 styles each deeply 2-lobed (the total number
of stigmatic branches thus 6 per flower). Fruits 3.5–5.5 mm in length,
4–5 mm in diameter, nearly spherical, 3-seeded (rarely 2-seeded by
abortion of 1 ovule), dehiscent. Seeds 3–4 mm long, oblong-ovate to
oblong-elliptic in outline, somewhat flattened and often slightly wedge-shaped,
the caruncle present as a small knob. July–October.
throughout the state but absent or uncommon in the western half of the
Glaciated Plains Division (eastern U.S. west to Minnesota, Nebraska, and Texas). Glades, upland prairies, sand prairies, and openings of bottomland forests; also
pastures, crop fields, fallow fields, ditches, levees, railroads, roadsides,
and open, disturbed areas.
variation in C. glandulosus requires much more detailed study. Numerous
varieties have been named in this widespread and variable species, which occurs
from North America to South America and in the Caribbean Islands, but a
comprehensive summary of variation in the species or even a key to
determination of all of the varieties does not appear to exist. Johnston (1958) treated three varieties in Texas. Webster (1967) further noted the
existence of several taxa described as species in Florida that are very closely
related to C. glandulosus, some of which might better be classified as
varieties. Missouri plants apparently correspond to var. septentrionalis,
the northernmost phase, which is robust but with relatively small, narrower
leaves having relatively sharply toothed margins, small seeds, and moderately
coarse, spreading pubescence. Its relationship to the more tropical var. glandulosus,
which apparently occurs as far north as Florida, remains to be elucidated.
Interestingly, although the variety is considered of conservation concern in a
few northern states, it is considered a crop weed in some southeastern states.