Tigridieae (Iridaceae) in North America: floral diversity, flower preservation methods and keys for the identification of genera and species

Abstract

Background: The tribe Tigridieae (Iridaceae) is a monophyletic group restricted to America. It includes bulbous perennial plants with plicate and isobilateral leaves. The inflorescence is a rhipidium and the floral structures are fugacious, very variable in shape, color and size. Tigridieae is taxonomically and morphologically complex. Its generic limits are unresolved and the vegetative uniformity of the tribe complicates species identification. Species are recognized by the position, shape and color of the tepals, stamens and stigma, characters that are difficult to observe in many herbarium specimens. Studied species: Sixty-seven species of the tribe Tigridieae. Study site and years of study: North America (Canada, United States of America and Mexico). The study was conducted from 2009 to 2015. Methods: Twenty-three herbaria, floristic studies and monographs were reviewed and specimens were collected in the field. Fresh dissections were performed in order to preserve the flowers and an analysis was conducted of the floral variation and distribution of the species of Tigridieae. Results: Keys for the identification of genera and species are presented. Photographs of the species and floral structures are included for their recognition. In addition, a method is described for dissecting and preserving flowers as herbarium specimens. Finally, geographic distribution data are presented. Conclusions:In North America, 67 species within14 genera of Tigridieae are known, of which 54 are endemic. Tigridieae exhibits wide floral diversity influenced by its pollinators and geographic isolation. This key for the Tigridieae of North America along with the photographs illustrating floral diversity will facilitate identification of species in the field. Keywords: Mexico, key, floral dissections, distribution, biodiversity, floral diversity.Tigridieae (Iridaceae) en Norteamérica: diversidad floral, métodos de preservación de sus flores y claves para identificación de géneros y especies Resumen Antecedentes: La tribu Tigridieae (Iridaceae) es un grupo monofilético restringido a América. Incluye a plantas bulbosas y perennes, con hojas plegadas e isobilaterales, inflorescencia en forma de ripidio, estructuras florales fugaces, muy variables en forma, color y tamaño. Tigridieae es complicada morfológica y taxonómicamente. Sus límites genéricos no están resueltos y su uniformidad vegetativa dificulta la identificación de las especies. Las especies son reconocidas por la posición, forma, tamaño y color de los tépalos, estambres y estigma, caracteres difíciles de observar en ejemplares de herbario. Especies en estudio: 67 especies de la tribu Tigridieae. Sitio de estudio y fechas: Norteamérica (Canadá, Estados Unidos de América y México). El trabajo se realizó de 2009 a 2015.Métodos: Se revisaron 23 colecciones botánicas, trabajos botánicos y se colectaron ejemplares en campo. Se realizaron disecciones en fresco para preservar las flores y se analizó la diversidad floral y distribución de las especies de Tigridieae. Resultad...

Filogeografía de Tigridia durangensis (Tigridieae: Iridaceae), una especie endémica de la Zona de Transición Mexicana

“…Es una tribu monofilética y agrupa 203 especies. Dentro de Tigridieae, la variabilidad morfológica de las flores contrasta con la uniformidad de las hojas y bulbos (Rodríguez & Sytsma 2006, Munguía-Lino et al 2017. Las plantas del género Tigridia Juss.…”