1. Claytonia virginica L. (Virginia spring beauty, spring beauty
C. virginica f. robusta (Somes) E.J. Palmer
& Steyerm.
C. ozarkensis John M. Mill. & K.L. Chambers
Pl. 506 a, b;
Map 2310
Plants perennial
herbs (annual elsewhere), with a globose to ovoid, brown, tuberous rootstock
(with taproots or rhizomes elsewhere), this 8–20 mm wide, usually positioned
well below the substrate surface. Aerial stems 1 to several, 5–20 cm long,
usually well-developed, erect to loosely ascending, sometimes sprawling, not
succulent or thickened, glabrous. Leaves basal and a single opposite pair along
the stems, glabrous. Basal leaves 1 or few (rarely more), 6–20 cm long, the
blade relatively thick, linear to narrowly oblanceolate or narrowly elliptic
(rarely broader), angled or tapered to a sharply pointed tip, long-tapered to
an indistinct, short to long petiole, green to dark green, sometimes
reddish-tinged. Stem leaves 4–15 cm long, sessile or with a short, indistinct
petiole, the blade relatively thick, linear to narrowly oblanceolate or
narrowly elliptic, occasionally more broadly elliptic, angled or tapered to a
sharply pointed tip, long-tapered at the base a single pair, variously sessile
to long-petiolate. Stipules absent. Inflorescences terminal, solitary racemes
4–18 cm long, short- to long-stalked (measured from above the pair of stem
leaves), with 5–18 flowers, all tending to be oriented toward 1 side of the
axis, only the basal 1(2) flower(s) subtended by a membranous to herbaceous
bract, this 2–9 mm long, narrowly lanceolate to ovate, more or less sheathing
the axis. Flowers mostly relatively long-stalked, the stalk continuing to
elongate after flowering, hypogynous; cleistogamous flowers absent. Calyces 5–7
mm long, the sepals overlapping, persistent at fruiting, remaining ascending
after flowering. Petals 5, 7–14 mm long, white or pinkish-tinged, usually with
pink venation, withering after the flowering. Stamens 5, the anthers pink
(white elsewhere). Ovary superior, the style 3-branched above the midpoint.
Fruits 2.5–5.0 mm long, ellipsoid to ovoid, with longitudinal dehiscence, the
valves remaining attached, the 1–6 seeds forcibly ejected. Seeds 1–3 mm long,
more or less circular (often minutely notched at the base) in outline, somewhat
flattened, the surface smooth, shiny, black (dull and/or pebbled elsewhere). 2n=12
to ca. 190. February–May.
Common
throughout the state (eastern U.S. west to Wisconsin and Texas; Canada).
Bottomland forests, mesic upland forests, banks of streams and rivers, upland
prairies, sand prairies, bases and ledges of bluffs, and occasionally margins
of sinkhole ponds; also pastures, cemeteries, lawns, railroads, and roadsides.
Claytonia
virginica holds the
distinction of having the longest recorded series of aneuploid chromosome
counts (Doyle, 1981; W. H. Lewis and Semple, 1977). In the St. Louis area
alone, W. H. Lewis et al. (1967) recorded plants with 2n=22–37 and
suggested that broader leaves are correlated with higher chromosome numbers.
Rare plants at the broadest-leaved extreme have been called f. robusta.
The rare Claytonia
ozarkensis was first described in late 2006 (J. M. Miller and Chambers,
2006). It was documented from a dozen herbarium specimens in the Ozark portions
of Arkansas and Missouri, as well as east-central Oklahoma. The Missouri
distribution included the type specimen from Ozark County and single historical
specimens from Jefferson and Stone Counties. These specimens were determined by
Steyermark (1963) as C. virginica f. robusta. Recent study of the
Missouri and Oklahoma specimens has determined that, in fact, Steyermark’s
determinations were correct and the plants in question are all merely
broad-leaved examples of C. virginica (Yatskievych et al., 2013).
Additionally, detailed searches by several botanists at the type locality in
Ozark County and the site in Stone county failed to disclose plants of C.
ozarkensis or suitable acidic rock outcrops for it to grow on. However, at
the type locality, broad-leaved individuals of C. virginica similar to
the C. ozarkensis type specimen were found intermixed with
narrower-leaved plants of that species. For these reasons, C. ozarkensis
must be excluded from the Missouri flora for the present and treated as endemic
to Arkansas. Because the type specimen of the species was misdetermined, the
taxon was of necessity renamed, C. arkansana Yatsk., R. Evans &
Witsell, and the name C. ozarkensis technically becomes a synonym of C.
virginica.
Claytonia
arkansana is
superficially less similar to C. virginica than to C. caroliniana
Michx., which is widespread in the eastern United States and adjacent Canada,
and to C. ogilviensis McNeill, a rare endemic in northwestern Canada. It
was distinguished morphologically from these taxa in the monograph of the genus
(J. M. Miller and Chambers, 2006, as C. ozarkensis). Subsequently, Croft
et al. (2011) provided genetic evidence to support the distinctness of the
Arkansas populations. It is restricted to horizontal ledges and tops of
sandstone bluffs where plants usually are rooted in relatively deeply incised
rock seams. Seed dispersal in the plants is unusual in that the inflorescences
become recurved back into the crevice as the fruits mature, depositing the
seeds back into suitable habitat adjacent to the maternal parent (Matthew
Albrecht, Missouri Botanical Garden, personal communication). When pressed and
dried, specimens of C. arkansana are easily differentiated from
broad-leaved plants of C. virginica because the leaves and stems become
very flaccid, thin, and translucent (whereas, plants of the latter species
generally remain firm and opaque). The key below, which is adapted from J. M.
Miller and Chambers (2006), provides additional characters to distinguish the
two. Because sandstone bluffs occur in several Missouri counties, it is possible
that this unusual rare species eventually may be discovered growing in the
state.