Phlegmariurus tico

Sorojsrisom, Elissa S., Alvarado-Rodrıguez, Olman & Testo, Weston, 2023, Goniopteris 3 tico (Thelypteridaceae), a New Hybrid Fern from Costa Rica, Systematic Botany (Basel, Switzerland) 48 (4), pp. 471-481 : 476

Etymology — “Tico ” is a colloquial Spanish-language term commonly used by inhabitants of Costa Rica to refer to themselves. In botanical nomenclature, has been incorporated in both generic names (e.g. Ticodendron Gomez-Laur. & L.D.Gomez , Ticodendraceae ) and specific epithets (e.g. Phlegmariurus tico A.Rojas , Lycopodiaceae ) of taxa endemic to Costa Rica, like this hybrid. It is used here as a noun in apposition.

Additional Specimens Examined — Costa Rica. — HEREDIA: Sarapiquı, La Selva Biological Field Station, 10.432 N, 84.0287 W, 100 m, 18 Jan 2015, M. Sundue 3931 (VT).

Although Goniopteris 3 tico superficially resembles G. nicaraguensis , it is readily distinguishable from that species by its short-creeping rhizome, irregularly lobed pinnae, and partially anastomosing veins. It could also be mistaken for G. mollis due to abundant white acicular hairs on both leaf surfaces, but it has much more deeply lobed pinnae, has at least some furcate hairs on the leaf axes, and has fewer and less regular vein anastomoses.

Goniopteris 3 rolandii (C.Chr.) A.R.Sm., which appears to be a hybrid of G. poiteana and Goniopteris tetragona ( Smith 1995) , shares the leaf division, irregularly anastomosing venation, and short-creeping rhizome of G. 3 tico , but differs by prominently setose sporangia and occasional proliferous buds at the base of distal pinnae. It is known from relatively few collections but is apparently widely distributed, with records from the Antilles, Nicaragua, Venezuela, and Ecuador ( Smith 1995).

This study also demonstrates the utility of target-capture DNA sequence data obtained with the GoFlag 408 probe set for characterizing hybrid origins in ferns. At least one other study used the same type of data and approach to detect hybrids in Australian Thelypteridaceae ( Bloesch et al. 2022) . Although our phylogeny resolves one subgenome of the hybrid as sister to a clade comprising Goniopteris oroniensis and multiple accessions of G. nicaraguensis , we exclude G. oroniensis as a candidate progenitor, as it is very rare and only known from a few localities in far southeastern Costa Rica ( Gomez 1978). When describing G. oroniensis, Gomez (1978) indicated that it was very similar to G. nicaraguensis and differed by conspicuously zig-zag rachises. The spores of the type specimen of G. oroniensis ( Ocampo 1635, CR, UC, US) are also irregularly and misshapen, suggesting that it may also be a hybrid with G. nicaraguensis as a parent. Along with confirming the hybrid origin of Goniopteris 3 tico , our phylogenomic analyses also indicate hybrid origins for at least two other taxa in our study set: G. poiteana and G. 3 rolandii. This approach shows promise for accelerating detection of hybridization in Goniopteris and other fern genera.

That this hybrid had not been previously recognized despite occurring in one of the most thoroughly studied field stations in tropical America highlights the cryptic nature of fern hybrids derived from progenitors with similar leaf morphologies. In these cases, study of morphology alone may not be sufficient to distinguish hybrids from their progenitors. Complementary data types such as DNA sequence data can play an important role in hybrid detection, as demonstrated here.