Phemeranthus aurantiacus
Phemeranthus calcaricus
orange fameflower
limestone fameflower
erect, simple or branching, slender to stout, sometimes suffrutescent.
ascending to erect, sometimes branching, ± tufted.
subsessile;
blade narrowly planate, linear to narrowly lanceolate or rarely oblanceolate, to 6 cm, base attenuate.
sessile;
blade terete, to 5 cm.
flowers usually solitary, sometimes in 2–3-flowered cymules.
cymose, overtopping leaves;
peduncle scapelike, to 15 cm.
sepals deciduous, ovate, sometimes cuspidate, 5–10 mm;
petals yellow or orange, sometimes reddish, rarely pinkish, obovate, 9–15(–25) mm;
stamens usually 20–30;
stigmas 3, linear;
pedicel often recurving in fruit.
sepals persistent, ovate, 3–4 mm;
petals rose-purple, elliptic to obovate, 8–10 mm;
stamens 25–45;
stigma 1, distinctly 3-lobed.
ovoid to globose, 4–7 mm.
ovoid to obovoid, 4–6 mm.
with arcuate ridges, 1.2(–1.7) mm.
without arcuate ridges, 1.2 mm.
= 48.
Phemeranthus aurantiacus
Phemeranthus calcaricus
A cladistic analysis of chloroplast ndhF sequence data (W. L. Applequist and R. S. Wallace 2001) indicated that Phemeranthus aurantiacus belongs in the same clade as Talinum paniculatum (Jacquin) Gaertner and the two other species of that genus that were sampled, rather than in a separate and rather distant clade containing P. mengesii, the only other species of Phemeranthus included in the study. The molecular evidence, together with the planate leaves and extended stem of P. aurantiacus, which are anomalous in Phemeranthus, suggest that perhaps this species should be restored to Talinum. However, in fruit and seed characters, the chief morphological bases on which Talinum and Phemeranthus are distinguished, P. aurantiacus clearly belongs in the latter.
Talinum angustissimum often has been held separate from Phemeranthus aurantiacus (T. aurantiacum), but the supposed distinctions break down in a continuum of intergradation, the other extreme of which was described as T. whitei. The former extreme, centered in southern Arizona, has yellow petals, very narrow leaves, slender stems, and small, globose capsules; the latter, centered in southern Chihuahua and northern Durango, has orange to reddish petals, broad leaves, stout stems, and large, ovoid capsules. The name T. lineare Kunth, which properly applies to a species from central Mexico, has been misapplied to some collections of P. aurantiacus from Texas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
A recent study strongly suggests that Phemeranthus calcaricus is a derivative of autotetraploid P. calycinus (W. H. Murdy and M. E. B. Carter 2001). Congruent with that hypothesis, one collection from a glade in Izard County, Arkansas (B. L. Lipscomb 1577, NCU), which is within the range of P. calycinus, appears to belong to P. calcaricus, which is known otherwise only from well east of the Mississippi River and outside the range of P. calycinus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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