In:
Systematic Botany, American Society of Plant Taxonomists, Vol. 33, No. 3 ( 2008-07-01), p. 598-612
Abstract:
Menyanthaceae consist of five genera of aquatic and wetland plants distributed worldwide. The three monotypic genera ( Liparophyllum , Menyanthes , and Nephrophyllidium ) are clearly differentiated morphologically, but the two larger genera ( Nymphoides and Villarsia )
contain several taxa of uncertain affinity. We undertook a phylogenetic analysis, using a combination of morphological and molecular data, to resolve relationships among species and to evaluate the current circumscription of genera. DNA sequence data for nuclear (ITS) and chloroplast ( rbcL and trnK/matK ) gene regions were largely congruent (by partition-homogeneity test), and a combined data phylogeny revealed several strongly supported relationships. Analyses using asterid outgroup taxa supported the monophyly of Menyanthaceae. Menyanthes trifoliata and Nephrophyllidium
crista-galli comprised a clade sister to the remainder of the family. Species of Nymphoides , except N. exigua , resolved to a single, deeply-nested clade, indicating that the floating-leaved habit is derived evolutionarily within the family. The genus Villarsia comprised
a paraphyletic grade toward Nymphoides , wherein the species resolved to three assemblages: (1) a shallowly nested clade containing V. albiflora , V. calthifolia , V. marchantii , V. parnassifolia , V. reniformis , and V. umbricola ; (2) an isolated
South African clade including V. manningiana and the type species, V. capensis ; and (3) a heterogeneous clade of taxa from three genera, including V. exaltata , V. lasiosperma , and V. latifolia , plus the anomalous species V. capitata , V. congestiflora , Liparophyllum gunnii , and Nymphoides exigua . Our results indicate that the genera Menyanthes , Nephrophyllidium , and Nymphoides should be retained as circumscribed, with the exception that Nymphoides exigua should be restored to Villarsia . The
genus Villarsia , however, eventually should be subdivided among monophyletic lineages, whereby in the strict sense Villarsia would contain only South African taxa.
Type of Medium:
Online Resource
ISSN:
0363-6445
DOI:
10.1600/036364408785679851
Language:
English
Publisher:
American Society of Plant Taxonomists
Publication Date:
2008
detail.hit.zdb_id:
2052625-8
SSG:
12
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