Generic limits in Polygonum and related genera (Polygonaceae) on the basis of floral characters

Abstract

RONSE DECRAENE, L.-P. AND AKEROYD, J. R., 1988. Generic limits in Polygonurn and related genera (Polygonaceae) on the basis of floral characters. In order to investigate the taxonomic value of a number of characters in the elucidation of relationships within the collective genus Polygonurn L., and segregate genera Atraphaxis L., Calligonum L., Pteropyrum Jaub. & Spach., Oxygonurn Burch., Fagofivrurn Mill., Hnrpagocarpus Hutch. & Dandy and Polygonella Michx., 83 species of the tribe Polygoneae emend. Jaretzky were studied. The following floral characters were examined: stamen number, insertion and external morphology; structure and morphology of the floral nectaries; vasculature and surface morphology of the tepals. Problems i n floral morphology in Polygonaceae are discussed, together with relationships within the Family. l'he tribal division proposed by Haraldson (1978) is supported, but a new and different delimitation of genera is proposed. The present data support a division of Polygonurn L. sensu lalo and its related taxa into two tribes: Polygoneae (containing Polygonum L. sensu slriclo, Fallopia Adans., Oxygonum Burch., Pterofivrum Jaub. & Sparh., Atraphaxis L. and Calligonum L.), and Persicarieae (containing Fagopyrurn Mill., Harpagocarpus Hutch. & Dandy, Persicaria Mill. and Koenigia L.). The genus Reynoulria Houtt. is included as a section of Fallopia Adans.; Bislorla Mill,, Aconogonon Reirhenb. and Touara Adans. are included within Persicaria Mill. A number of new combinations are proposed in Persicaria and Fallopia.

Phylogeny and systematics of Indian Polygonum sensu lato in the subfamily Polygonoideae based on ITS sequences of nuclear ribosomal DNA

“…in the cladogram, thus confirming the systematic invalidity of this section. This conclusion is also in line with the views proposed by Ronse De Craene and Akeroyd (1988). We also carried out studies on population structure and genetic variation of P. barbata.…”

“…Therefore, the traditional definitions of Polygonum and other polygonaceous taxa are useful for identification, but not necessarily for elucidation of evolutionary relationships. The traditional method of classification has led to disagreement among taxonomists over which species should be included in the Polygonum and which taxa should be elevated to their own genus because of the presence of at least one distinguishing characteristic (Meisner, 1826;Bentham and Hooker, 1880;Dammer, 1892;Gross, 1913;Hedberg, 1946;Graham and Wood, 1965;Holub, 1971;Haraldson, 1978;Ronse De Craene and Akeroyd, 1988;Hassan, 1997;Ronse De Craene et al, 2000;Hong et al, 2005). Morphological, cytological, palynological, and anatomical data, although useful in resolving some questions in the circumscription and relationship of genera, have not provided a consensus regarding relationship within the genera.…”

“…Recent biomolecular studies (Cuenound et al, 2002;Lamb Frye and Kron, 2003;Kim et al, 2005; Kim and Donoghue, 2008; Sanchez and Kron, 2008) have revealed that P. sensu lato is polyphyletic and should be divided into several genera. The treatment of the Polygonoideae subfamily by Haraldson (1978) and Ronse De Craene and Akeroyd (1988) have suggested that the Polygonum species, in the broad sense, be segregated into two separate tribes: Polygoneae and Persicarieae. The Persicarieae tribe is characterized by the presence of tepals with three nervatures departing from the base (with some exceptions in Fagopyrum), rectangular to elongate epidermic cells with straight or undulating anticlinal walls, and longitudinal and often continuous smooth or striate cuticles.…”

The Japanese knotweed invasion viewed as a vast unintentional hybridisation experiment

“…Fallopia x. conollyana represents a most unexpected hybrid between two non-sympatric taxa, an octoploid (2n ¼ 88) rhizomatous herb and a diploid (2n ¼ 20) twining woody climber. At the time of its discovery in the 1980s, it was regarded taxonomically as an intergeneric cross, and its existence provided additional support for Ronse Decraene and Akeroyd's (1988) decision to merge the genus Reynoutria with the older genus Fallopia. There are two major barriers to the spread of F. x conollyana: firstly, the general inability of seed from Japanese knotweed to overwinter, germinate and establish spontaneously in Europe, and secondly, the conflict between the parental overwintering strategies: woody stems versus rhizomes.…”

Anticancer potential of selected Fallopia Adans species

“…The low production cost of the plant extracts compared to the pure compounds and the synergistic effects of the natural compounds are the main advantages for using natural extracts (21). Fallopia Adans is a plant genus which contains approximately 15 species (22)(23)(24). The species are widespread over the northern hemisphere (25).…”