5d. Epilobium Linnaeus sect. Cordylophorum (Nuttall ex Torrey & A. Gray) P. H. Raven, Ann. Missouri Bot. Gard. 63: 333. 1977.
[E]
Epilobium [unranked] Cordylophorum Nuttall ex Torrey & A. Gray, Fl. N. Amer. 1: 488. 1840; Cordylophorum (Nuttall ex Torrey & A. Gray) Rydberg
Herbs perennial, suffrutescent or rhizomatous. Stems ± woody at base, epidermis usually peeling proximally. Leaves opposite proximal to inflorescence, alternate distally. Flowers actinomorphic or slightly zygomorphic; floral tube sometimes with bulbous base, without scales inside; petals rose-purple or cream-yellow; pollen in tetrads; stigma 4-lobed. Capsules fusiform to subcylindrical, splitting to base, central column persistent, pedicellate to subsessile. Seeds 1–8+ per locule in 1 row, obovoid to broadly obovoid, prominently constricted near micropylar end, coma present.
Species 3 (3 in the flora): w United States.
Section Cordylophorum consists of three perennial self-compatible but outcrossing species, each with an unusual and restricted distribution in western North America. All three species, which P. H. Raven (1976) placed in two subsections, share a chromosome number of n = 15 (found also in sects. Zauschneria and Epilobiopsis) and several unusual pollen, seed, and leaf character states. However, as Raven noted, this section can be delimited only by a combination of characteristics, with no unequivocal synapomorphy. S. R. Seavey and Raven (1977c) reported hybrids between E. suffruticosum and E. nevadense (only 24% pollen-fertile), and between E. nevadense and E. nivium (99% fertile). Attempts to cross any of these species to taxa of sect. Zauschneria (n = 15), sect. Xerolobium (n = 12), and sect. Epilobium (n = 18) failed in all cases. D. A. Baum et al. (1994) found only weak support for the monophyly of this section. Pending additional data, the similarities among these species are emphasized and the current classification is here retained.
