Spore types in Mexican and Mesoamerican species of Pteris L. (Pteridaceae)

Abstract

Spore morphology of 25 Mexican and Central American species in Pteris were studied. This was accomplished using scanning electron and light microscopy. Spores are trilete, tetrahedral, with plane or slightly convex proximal faces, concave only occasionally, and convex or hemispherical distal faces. In addition to these general features and size, we also considered the following traits: (a) cingulum; (b) presence of a commissural flange; (c) types of macro-ornamentation; (d) ornamentation in distal and proximal faces. In general, distal and proximal faces of Pteris spores are divided by a circumfluent cingulum, lacking ornamentation, infrequently not well defined, or interrupted. The laesura have a commissural flange in almost half of the studied species. The most common macro-ornamentation is muriform, less frequently steliform or buliform. Ornamentation is usually different on both sides of the spore. In most of the studied species occasional to abundant globules are present on the spore surface. The combination of these traits allows us to recognise six spore types, which are described in detail. These spore types disagree with groups of species of Neotropical Pteris previously studied using other characteristics (mainly frond architecture and molecular data). Our results show that the use of spore characteristics can help clarify infrageneric taxonomy in Pteris.

Keywords:

• ferns
• Mesoamerica
• Mexico
• palynology
• scanning electron microscopy

Acknowledgements

The authors are very much indebted to the Tiburcio Láes for his invaluable work with the MEB photographs at the Instituto de Ecología, A.C., Xalapa, Veracruz, México. The authors appreciate the invaluable comments to the manuscript made by Marcelo Arana, Universidad de Río Cuarto, Argentina. Many thanks to Olga Martha Montiel, Missouri Botanical Garden, USA, for providing important literature from the Missouri Botanical Garden. The facilities provided from the different Herbaria are appreciated. Thanks to Alejandra Valencia, Universidad Veracruzana, México, for the logistic support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Specimens investigated

Pteris altissima Poir.: (a) México: Gómez-Pompa et al. 5355 (XAL); (b) México: Ventura 12775 (ENCB); (c) Costa Rica: Martén 827 (CR); (d) México: Linden s.n. (BR); (e) Colombia: Forero & Jaramillo N.2.510 (XAL).

Pteris biaurita L.: (a) México: Riba et al. 1254-d (UAMIZ); (b) Costa Rica: Induni 19 (INB).

Pteris chiapensis A.R.Sm.: (a) México: Rzedowski 23584 (ENCB).

Pteris cretica L.: (a) México: Ventura 16907 (ENCB); (b) México: Rzedowski 42402 (ENCB); (c) Guatemala: Lundell & Contreras 19736 (MO); (d) México: Yatskievych & Gastony 89-208 (MO); (e) México: Orcutt 0428 (MO); (f) Honduras: Moran 05668 (MO); (g) México: Hammel et al. 15794 (MO); (h) México: Rodríguez et al. 00067 (MO); (i) México: Lorence & Cedillo 04168 (MO); (j) Guatemala: Molina & Molina 26686 (MO).

Pteris ensiformis Burm.f.: (a) México: Palacios-Rios s.n. (XAL).

Pteris erosa Mickel et Beitel: (a) México: McVaugh 23376 (ENCB).

Pteris grandifolia L.: (a) México: Díaz-Barriga & Zamudio 4643 (ENCB); (b) México: Ventura 11462 (MEXU); (c) Costa Rica: Grayum & Hammel 9547 (INB); (d) Costa Rica: Reyes & Rojas 243 (INB); (e) Cuba: Cárdenas s.n. (XAL).

Pteris livida Mett.: (a) Costa Rica: Fuentes 759 (INB); (b) Costa Rica: Rivera 118 (INB).

Pteris longifolia L.: (a) México: Ventura 12512 (MEXU); (b) Guatemala: Croat 24691 (XAL).

Pteris multifida Poir.: (a) USA: Correll & Correll 09396 (MO); (b) USA: Hill 19480 (MO).

Pteris muricata Hook.: (a) México: F. Ventura 15768 (MEXU); (b) México: Martínez et al. 13221 (MEXU); (c) Costa Rica: Moran 4164 (CR).

Pteris muricatopedata Arbeláez: (a) Costa Rica: Rojas 816 (CR).

Pteris muricella Fée: (a) México: Fink 19 (MO); (b) Costa Rica: Pittier 7565 (BR).

Pteris navarrensis H.Christ: (a) Costa Rica: Stolze 1476 (CR); (b) Panamá: Snapp et al. 2047 (CR).

Pteris orizabae M.Martens et Galeotti: (a) México: Ventura 4802 (ENCB); (b) México: Riba & Pérez 874 (UAMIZ); (c) Nicaragua: Croat 43115 (CR); (d) México: Palacios-Rios 5130-5134 (XAL).

Pteris paucinervata Fée: (a) México: Linden 63 (BR); (b) México: Calzada et al. 8924 (XAL); (c) Costa Rica: Jiménez 1183 (CR).

Pteris plumula Desv.: (a) México: Greenman 141 (F); (b) México: Morelos & Lyonnet 1372 (CAS); (c) Costa Rica: Pittier 1058 (BR); (d) Costa Rica: Pittier 8494 (BR); (e) México: Palacios-Rios 5135 (XAL).

Pteris podophylla Sw.: (a) México: Ventura 11122 (MEXU); (b) México: Pringle 7885 (MO); (c) Costa Rica: Lent 4041 (CR).

Pteris propinqua J.Agardh: (a) Costa Rica: Grayum et al. 8796 (CR); (b) Honduras: Nelson et al. 4060 (CR); (c) México: Hernández-Gómez s/n (XAL); (d) Panamá: Tyson et al. 4700 (MO); (e) Brasil: Sperling et al. 05932 (MO); (f) Panamá: Duke & Bristan 00448 (MO); (g) Panamá: Croat 10960 (MO); (h) Nicaragua: Grijalva & Araquistain 00138 (MO).

Pteris pulchra Schltdl. et Cham.: (a) México: Rubio 2705 (CAS); (b) México: Calzada 5459 (UAMIZ).

Pteris pungens Willd.: (a) México: Orcutt 3376 (MEXU); (b) México: Riba & Pérez 808 (XAL); (c) Costa Rica: Croat 35726 (CR); (d) México: Acosta & Mendoza 03140 (XAL).

Pteris speciosa Mett. ex Kuhn: (a) Costa Rica: Grayum et al. 7808 (CR).

Pteris tremula R.Br.: (a) USA: Bold s.n. (US); (b) USA: Politi S-1974-58 #1 (US); (c) México: Díaz & Carranza 6560 (IEB).

Pteris tripartita Sw.: (a) Costa Rica: Grayum 8035 (CR).

Pteris vittata L.: (a) México: Clausen 7640 (US); (b) México: Knobloch 2013 (US); (c) México: Palacios-Rios et al. 3690 (XAL); (d) Costa Rica: Gómez 6833 (CR); (e) Cuba: Valdés s.n. (XAL).

Additional information

Funding

The authors appreciate the logistic and financial support from Victor Rico-Gray, Universidad Veracruzana, México, the financial support from the Missouri Botanical Garden, Mellon Foundation, Latin American Studies, Conabio (J009, V039); Conacyt (D112-904011, 1360-N9206, 4102p-N9607, 35123-V, POSGR0210722) and IdeaWild as well as from the Instituto de Ecología, A.C., and the Universidad Veracruzana, Xalapa, Veracruz, México. Part of the work has been accomplished thanks to the support of the Universidad Complutense de Madrid, Madrid, Spain, through the Research Group Funds (Group 910801, Biodiversity and Taxonomy of Cryptogamic Plants).