A Treatment of American Xyridaceae Exclusive of Xyris

Abstract

This work is the first part of a treatment of New World Xyridaceae, exclusive of Xyris, and is focused on the other four genera that make up this family, namely Abolboda (21 species), Achlyphila (one species), Aratitiyopea (one species), and Orectanthe (two species). The treatment is conventional, providing (1) a general description, (2) a key to the genera, (3) detailed descriptions of each of the four genera and keys to their species where needed, and (4) illustrations of species and varieties together with synonymy and geographic distribution. Some realignment of taxa IS presented. Two new species, Abolboda dunstervillei and A. scabrida, and one new variety, Abolboda acaulis var. scaposa, are proposed.

Floral Anatomy of Xyrids (Poales): Contributions to Their Reproductive Biology, Taxonomy, and Phylogeny

“…Xyridaceae includes five genera and ;300 herbaceous species (Kral 1998). Xyris is the largest genus of this family and comprises ;270 species found across a pantropical distribution, mainly in Central and South America (Kral 1998).…”

Floral ontogeny and vasculature in Xyridaceae, with particular reference to staminodes and stylar appendages

“…6f, g). Conspicuous staminodes are absent in Orectanthe and in most species of Abolboda, though filiform structures occur in the staminode position Data sources morphological data from Kral (1992Kral ( , 1998 and this paper; anatomical data as cited in (Figs. 2e, 7c).…”

“…However, one monotypic genus, Achlyphila (A. disticha Maguire and Wurdack), has not yet been sequenced for molecular data; its placement is critical for analysis of character evolution in Xyridaceae. Achlyphila disticha is a rare species that grows in bogs at high altitudes (800-2300 m) in the Venezuelan Cerro Neblina; it is reportedly the only species of Xyridaceae in which the stamens are free from the petals (Kral 1992), though Carlquist (1960) illustrated the stamen bundles detaching from the petal bundles in this species. Achlyphila shares several flower, ovule and pollen characters with Abolboda, including characteristically sphaeroidal, inaperturate pollen; however, the pollen exine of Achlyphila lacks the characteristic spines of Abolboda grains, instead possessing only the small aggregated pila (rod-like rounded elements) that also occur on pollen of Xyris and other Xyridaceae (Carlquist 1960;Campbell 2012).…”

Inflorescence Architecture and Floral Morphology of Aratitiyopea lopezii (Xyridaceae)

“…The gynoecium of Achlyphila is incompletely known with respect to the surface of the stigma, and fusion of the carpels within the ovary and through the style. While it appears to lack appendages (Maguire and Wurdack 1960;Kral 1998), it should be noted that the delicate appendages in Abolboda are sometimes impossible to detect, especially in rehydrated flowers (Kral 1992, pers. obs.…”

“…Xyridaceae are characterized by a scapose spike inflorescence, and the few exceptions to this growth form (i.e., some Abolboda species, Achlyphila, and Aratitiyopea) have not been critically evaluated. In the taxonomic literature, the inflorescence of Aratitiyopea is described as a bracteate hemispheric capitulum (Steyermark and Berry 1984;Kral 1992Kral , 1998 (Smith 1951). While the inflorescence structure is largely uniform in Xyridaceae, it has long been noted that floral morphology is heterogeneous (Maguire and Wurdack 1960;Dahlgren et al 1985;Rudall and Sajo 1999; Table 1).…”