Campylopus julaceus, AND

T, Cíntia Aparecida, Araújo, eixeira, Peñaloza-Bojacá, Gabriel Felipe, De, Bárbara Azevedo, Oliveira & Maciel-Silva, Adaíses S., 2020, A morphometric comparison of two sympatric Campylopus Brid. (Leucobryaceae, Bryophyta) species, Cryptogamie, Bryologie 20 (19), pp. 239-253 : 245-250

CAMPYLOPUS JULACEUS AND C. LAMELLATUS DO NOT FORM TWO MUTUALLY EXCLUSIVE GROUPS

Among the main characters used to distinguish the two species, statistical differences were recorded when we analyzed variations in “leaf apex widths” (trait 6) and “width of the leaf in the end lamina” (trait 7) measured on the shoot apex (Discriminant analysis). Although other traits related to cell size (wide and length) had contributed to discriminate both groups, when basal and middle sections of shoots were analyzed, all these traits are very unstable among shoots of

C. julaceus C. lamellatus C. julaceus (holotype) Simple Euclidian Distance Simple Euclidian Distance

the same taxon. Thereafter those variations were only slight, because there was a strong overlap (see Fig. 4 ). In the UPGMA trees, shoots of C. julaceus were intermingled with those of C. lamellatus . That same pattern was repeated independent of the leaf section considered (base, middle, or apex). Although the MRPP test indicated a significant split between the two groups ( C. julaceus and C. lamellatus ), they are weakly cohesive. Additionally, the PCA analysis demonstrated that the two species overlap one another. The morphometric data in our study confirmed the morphological similarities of the two species, highlighting that the observed differences are likely not significant enough to segregate them into two distinct taxa.

In their descriptions of C. julaceus, Een (1989) and Santos (2011) mentioned the similarity of that species to C. lamellatus (previously as C. pilifer ). Santos (2011) reported that the morphological traits of C. lamellatus leaves are quite similar to those of C. julaceus . Additionally, she noted that herbaria voucher specimens containing both species appear to have similar leaves, except for the leaves in the comal tufts (apical section of shoot) of C. julaceus . Similarly, Frahm (1991) reported that sex-expressing plants of C. julaceus differ in terms of the terminal tuft, with distinct leaves encircling several gametangia. In fact, statistical differences in traits as “leaf apex width” and “width of the leaf in the end lamina” between both taxa emphasize the morphological dissimilarities between C. julaceus and C. lamellatus . In the present study, plants morphologically recognized as C. lamellatus and C. julaceus appear to actually represent the same taxonomic unit. As suggested by other authors ( Een 1989; Santos 2011), C. julaceus could simply represent the reproductive phase of the C. lamellatus (or C. pilifer in other world places). In addition of the presence of sexual branches containing gametangia in the comal tuft of C. julaceus , we also found asexual propagula (e.g., deciduous branches) near them. This system may be beneficial because the plants appear to allocate energy to produce several vegetative propagula simultaneously with sexual branches (female or male gametangia), increasing the chances of offspring output.

Campylopus lamellatus and C. julaceus seem to belong to a complex of morphologically similar species, which also include the invasive C. introflexus (Hedwig)Bridel and C.pilifer (restricted to old world, Gama et al. 2017). Campylopus introflexus differs from C. lamellatus / C. pilifer because the strongly recurved hyaline leaf apex and the dorsal costal lamellae composed of only 1-2 cells in the latter ( Gradstein & Sipman 1978; Frahm 1991; Gama et al. 2016). Several inventories or local floras have associated the two species, as intermediate specimens have been described that are often mistakenly identified ( Frahm 1991; Frahm & Stech 2006). C lamellatus and C. pilifer have central lamellae (in cross section) in a conspicuous V-shaped pattern, and the former presents lamellae consisting of 5-6 cells different from C. pilifer with 3-4 cells ( Frahm 1991; Gama et al. 2017). Campylopus julaceus , as explained above, is very similar to C. lamellatus / C. pilifer and it is commonly treated as those species ( Sharp et al. 1994; Santos 2011). Additionally, Frahm (1991) also recognized C. julaceus ssp. arbogastii in Africa as a morphologically distinct taxon (i.e. shorter lamellae at the costa) with similar niche to C. julaceus in the Southeastern Brazil. Evolutionary studies involving all of those related Campylopus species, at a broader geographical scale (phylogeography) will be needed, however, to clarify the phylogenetic relationships of that species complex.

Figures

FIG. 4. — Principal Components analysis (PCA) of the leaf characters of the basal, middle, of apical the shoots of C. julaceus A. Jaeger (including the holotype) and C. lamellatus Mont.