Cryptic species in the fern Ceratopteris thalictroides (Parkeriaceae). III. Referential diagnostic characters of three cryptic species

Abstract

Three cryptic species of Ceratopteris thalictroides, named the south type, the north type and the third type, were examined for their morphological characteristics, using sporophytes cultivated under common conditions. The discriminant analysis for leaf characters followed by one-way layout ANOVA or Kruskal-Wallis test for selected combinations of characters revealed that the following characters may be effective for identifying the three types: the relative lengths of stipe to blade and to pinna, the degree of dissection, the segment densities on rachis and pinna rachis, and the elongation degree of ultimate segments. The number of annulus cells on sporangia also proved to be a possible distinguishing character. As morphological data were obtained from a limited number of cultivated sporophytes, they are regarded as not definitive, but only referential diagnostic characters of the types and should be utilized not solely, but collectively, to avoid identification errors of the types. An identification trial using herbarium specimens proved these diagnostic characters to be useful to a considerable degree.

Ceratopteris chunii and Ceratopteris chingii (Pteridaceae), two new diploid species from China, based on morphological, cytological, and molecular data

“…The genus Ceratopteris is an aquatic or subaquatic annual plant, distributed in tropical and subtropical regions worldwide ( Brongniart, 1821 ; Lloyd, 1974 ; Masuyama et al., 2002 ). However, because of the high degree of polymorphism within the genus, several reproductively isolated taxa are morphologically indistinguishable ( Grant, 1981 ; Paris et al., 1989 ; Masuyama et al., 2002 ; Masuyama, 2008 ). This phenomenon strongly suggests that many cryptic species exist in Ceratopteris ( Liao et al., 2011 ; Kinosian et al., 2020a ).…”

Species Occurrence, Hybridization and Speciation in Postglacial East and South Asia

“…Sequential studies have provided evidence that they are of hybrid origin and have a different number of chromosomes (Adjie et al, 2007;Masuyama, 2008). Although a detailed diagnosis of the characters of the species is analyzed for the final taxonomic treatment, the continuous variation in morphologies remains elusive (Masuyama, 2008;Masuyama & Watano, 2010).…”

Global transcriptome analysis and characterization of Dryopteris fragrans (L.) Schott sporangium in different developmental stages

“…The sporangium of ferns, the place that produces spores, plays an important role in the propagation of the plants, similar to that of the flower and fruit of flowering plants. At present, a number of investigations of the morphological development, evolution and functions of the sporangium have been reported [ 1 – 4 ], but little is known regarding the transcriptome of fern sporangium.…”