John E. Averett

Polyploidy in plant taxa: summary.

The preceding seven papers deal with the distribution and evolutionary significance of Polyploidy in each of the major plant taxa. Polyploidy, the multiplication of entire chromosomal complements, is the most widespread and distinctive cytogenetic process affecting higher plant evolution. Approximately 36% of the species of flowering plants have gametic chromosome numbers which are multiples of the basic diploid number found within their respective genera, but between 70 and 80 percent may, in fact, have Polyploidy in their evolutionary history. The percent of intrageneric Polyploidy in ferns is even higher and the occurrence of intergeneric Polyploidy is equivalent to that in angiosperms. Studies to date have been largely confined to the aforementioned groups, especially the dicotyledonous angiosperms. However, the preceding papers suggest that Polyploidy may be an important aspect of evolution among at least certain groups of the thallophytes. The only group in which Polyploidy is con-spicuously rare is the gyminosperms.

Flavonoid systematics of ten sections of Ludwigia (Onagraceae)

Abstract Data for the flavonoids of 19 species in 10 sections of Ludwigia are presented. Eight flavonoids, comprising four glycoflavones, of which vitexin and isovitexin are reported for the first time in Ludwigia, and four flavonol glycosides, based on quercetin, are present in these species. Each section treated here has either glycoflavones or flavonols; presence of only onte class is considered to be advanced in the genus as a whole, compared with the presence of both glycoflavones and flavonols in the more generalized sects Myrtocarpus Cinerascentes, and Pterocaulon, which were examined earlier. Only glycoflavones are present in sects Macrocarpon (four species), Seminuda (five species), the ditypic African sect. Africana, the monotypic African sects Brenania, Cryptosperma, and Prieurea, the monotypic east Asian sect. Nipponia, and the monotypic pantropical section Fissendocarpa. Only flavonols are present in the monotypic Old Wodd section Caryophylloidea and sect. Oligospermum, which comprises nine species widespread in the OId and New Worlds.

Flavonoid variation in Xanthisma texanum: Infrapopulation and interpopulation variation

Fourte en flavonoids were isolated from Xanthisma texanum. Chemosystematic interpretations are made concerning the origin and distribution of the infraspecific taxa of the species. The flavonoid chemistry of Xanthisma texanum DC. (Asteraceae) was investigated as part of a cytological and systematic study of the monotypic genus (1, 2). Flavonoid profiles were obtained using standard procedures (3), and tentative identifications of some compounds have been completed (Table 1). Fourteen compounds were isolated and ten were used for systematic conclusions given below: quer- cetin (1), quercetin-3-O-glucoside (9), quer- cetin-3-O-glycoside (10), luteolin (2), luteolin- 7-O-glucoside (6), a flavonol-7-O-glucoside (12), an anthocyanin (13), a flavanone (4), and unknown flavonoids.

Glycoflavones in Circaea

Hydrolysates of methanolic leaf extracts of Circaea yield the glycoflavones vitexin, isovitexin, vicinin-1, and vicinin-2. Additional flavonoids are found in the unhydrolyzed extracts. Previous studies of Onagraceae report only flavonols and one chalcone. Circaea is assigned to a monogeneric tribe of Onagraceae and has no clear relationship to any other group within the family. The presence of glycoflavones in Circaea serves to underscore the distinctiveness of the genus.

Flavonoids in some monotropoideae

Abstract Flavonoid glycosides are either lacking or comprise simple profiles in five species representing four genera of the mycotrophic, achlorophyllous Monotropoideae of the Ericaceae. Monotropa hypopitys and Pterospora andromedea afforded no flavonoids while the profiles of M. uniflora Hemitomes conjestum and Sarcodes sanguinea cornprise monoglycosides and digylcosides of kaempferol and quereetin, although not all taxa have all compounds. Hemitomes also possess isorhamnetin 3- O -rutinoside The red colour of Sarcodes arises from a pelargonidin xyloside. The observed flavonoid profiles are more similar to the simple profiles reported for members of the Pyroloideae than they are to those of the Ericaceae sens str.

Eight flavonol glycosides in Pyrola (pyrolaceae)

Abstract As part of a general survey of the flavonoids of Pyrolaceae, the flavonoids of Pyrola virens and P. chlorantha were investigated. Eight flavonol glycosides based upon kaempferol, quercetin and rhamnetin were identified from each of the two species. Two of the glycosides, rhamnetin 3,3′,4′-tri- O -glucoside and rhamnetin 3- O -arabinoside-3′,4′-di- O -glucoside are previously unreported and further, represent an unusual pattern of glycosylation. The similarity of flavonoids and the presence of the unusual substitution pattern supports a conspecific status for the two taxa.

The Flavonoids and Flavonoid Systematics of Circaea (Circaeeae, Onagraceae)

Foliar flavonoid data are given for 13 of the taxa recognized in Circaea and for six of the nine known naturally occurring hybrids. Analysis of 113 populations revealed the presence of eight glycoflavones, two flavones, and two flavonols in the genus. The glycoflavones are orientin, isoorientin, isoorientin 0-acylate, vitexin, vitexin 0-acylate, isovitexin, isovitexin 0-acylate, and vicinin-1. Apigenin 7-0-glucoside and luteolin 7-0-glucoside are the two flavones and kaempferol 3-0-glucoside and quercetin 3-0-glucoside are the two flavonols. Circaea differs from other genera of the Onagraceae investigated in exhibiting considerable interspecific and interpopulational vari- ation in flavonoid composition. Two groups of species can be recognized in Circaea based on flavonoid data; the same two groups are also recognized using morphological criteria. As in other Onagraceae, Circaea shows reduction in structural diversity and overall number of compounds with

Flavonoids of the North American species of Leucophysalis (Solanaceae)

Abstract The known flavonoids, quercetin 3-rutinoside-7-glucoside, kaempferol 3-rutinoside-7-glucoside, quercetin 3,7-diglucoside, rutin, kaempferol 3-rutinoside, quercetin 3-glucoside, kaempferol 3-glucoside, quercetin 7-glucoside, and kaempferol 7-glucoside were found in leaf extracts of Leucophysalis nana and L. grandiflora ; the latter species also contained kaempferol 3,7-diglucoside.

Flavonoids of Rhynchocalycaceae (Myrtales)

Rhynchocalycaceae is a monotypic family represented by the rare Rhynchocalyx lawsonioides from South Africa. Although unquestionably myrtalean, it is isolated in the order with closest affinity to Alzatea verticillata in the monotypic Alzateaceae. Foliar flavonoids of Rhynchocalyx are reported for the first time. The flavonoid pattern comprises five quercetin 3-0-glycosides, present in approximately equal concentrations. These are quercetin 3-0-glucoside, 3-0-diglucoside, 3-0-rhamnoside, 3-0-xyloside, and 3-0-galactoside. Quercetin 3-0-glucoside and quercetin 3-0-diglucoside also occur in Alzatea. The pattern agrees with the typical profile of the Myrtales in which flavonols are common and flavones are rare. It differs in absence of myricetin, which is frequently found in the order. No more specific relationships are possible based on these flavonoid data due to the generalized nature and widespread occurrence of the compounds. Rhynchocalycaceae is a newly recognized monotypic family based on the rare Rhynchocalyx lawsonioides Oliv. from Natal, South Africa. It has been regarded generally as a genus of the Lythraceae, related to Lawsonia in subtribe Lagerstromiinae (Oliver, 1895; Sprague & Metcalfe, 1937) although that position was rejected by the monographer of the family (Koehne, 1903). Recently, it was included in a remodeled Crypteroniaceae as sole member of the subfamily Alzateoideae, tribe Rhynchocalyceae (van Beusekom-Osinga & van Beusekom, 1975). Anatomical, embryological, and morphological data now support the relationship of Rhynchocalyx to the unigeneric Alzateaceae but reflect a degree of isolation that merits its recognition as a separate family (Johnson & Briggs, 1984; Graham,

The flavonoids of Margaranthus

Abstract Four flavonols based on either quercetin or kaempferol are found in Margaranthus . The compounds are uniform throughout the populations examined and no evidence is present for the recognition of more than one species. The flavonols are similar to those found in related in genera, and do not provide a basis for the exclusion of Margaranthus from the subtribe Solaninae.