Campyloneurum C.Presl, Tent. Pterid.

Smith, Alan R., Kessler, Michael, León, Blanca, Almeida, Thaís Elias, Jiménez-Pérez, Iván & Lehnert, Marcus, 2018, Prodromus of a fern flora for Bolivia. XL. Polypodiaceae, Phytotaxa 354 (1), pp. 448-450 : 448-450

Campyloneurum C.Presl, Tent. Pterid. 189. 1836.

Campyloneurum is a neotropical genus comprising over 55 species, with 26 species known from Bolivia. The species were provisionally keyed and several new ones described by Lellinger (1988). León (1992) revised the genus in an unpublished Ph.D. thesis, and contributed ( León 1993) a treatment of Peruvian species in Tryon & Stolze (1993). Two subgenera are currently recognized: Campyloneurum and Decurrentia R.C.Moran & Labiak that include entire and pinnate-leaved species, respectively ( Moran & Labiak 2017). Species occupy a wide variety of habitats, from sea level to above 4000 m in open and forested vegetation, and can be terrestrial, epipetric, epiphytic, or rarely hemiepiphytic; some species have twining rhizomes. The genus is characterized by having anastomosing venation, the areoles with excurrent veinlets (cyrtophlebioid venation: hence the synonymous genus Cyrtophlebium R.Br. , type C. repens ), and 2(–3) rows of sori between adjacent lateral veins; sometimes, these excurrent veinlets fully divide the areoles. Venation characters distinguish Campyloneurum from its two closest allies, Niphidium and Microgramma ; in addition, Campyloneurum differs in having sori that occupy a medial or subapical position on excurrent veinlets, especially in entire-leaved species. Most species have entire leaves; there are three pinnate-leaved species, one of which occurs in Bolivia ( C. magnificum ). Characters distinguishing the various species involve details of venation (regularity of anastomoses), visibility and prominence of the main lateral veins, and whether the included veinlets in the areoles fully divide the areoles (or not); whether the rhizomes are long- or short-creeping (internode length), their thickness and glaucousness (presence or absence); petiole length relative to blade length; blade base (long- vs. short-attenuate, or more abruptly reduced); laminar pubescence (if any); number of rows of sori between main lateral veins (correlated with complexity of venation); and various rhizome scale characters (color, clathrateness, size, apex shape, aspect). Specimens without rhizomes may be difficult to identify. All species counted show a base chromosome number of x = 37; polyploids are known, and hybridization is suspected, but not well documented. Spores are bilateral, with a verrucate perispore ( Giudice et al. 2004).

Several species ( Campyloneurum amphostenon , C. angustifolium , C. fuscosquamatum , C. phyllitidis , and C. repens ) from Bolivia and neighboring countries are traditionally used as folk-medicinals ( Macía 2004, Navarrete et al. 2006).

Campyloneurum appears to be sister to Niphidium , and this combined clade sister to Microgramma ( Schneider et al. 2004; Otto et al. 2009; Labiak et al. 2017). With the exception of Polypodium s.s. and Pleurosoriopsis , all genera within subfam. Polypodioideae are most species-rich in South America, and it is clear that these genera all arose and radiated in this area, including a few that have amphi-oceanic congeners ( Microgramma and Pleopeltis in Africa and on islands of the Indian Ocean, e.g., Madagascar).