Dieter H. Wilken

Flavonoid and anthocyanin patterns and the systematic relationships in Collomia

Abstract Analyses of extracts among populations of the 14 species of Collomia revealed the occurrence of 13 mono-, di- and triglycosides based on the flavonoids, acacetin, kaempferol, patuletin and quercetin. The glycosides included those having arabinose, galactose, glucose and rhamnose as mono-, bio- or triosides at the 3-, 5-, 3,7- or 7-position. Analyses of floral extracts from ten species revealed the occurrence of two anthocyanins, cyanidin and delphinidin 3-( p -coumarylglucosyl)-5-glucoside. Nearly all the species express distinctive flavonoid patterns, although the differences are based on relatively minor changes in position or type of glycosidic substitution. Use of the minimum biosynthetic step distance (MBSD), an index of similarity, revealed that a mean of 5.6 steps separated the 14 species. The four perennial species of section Collomiastrum showed a high degree of similarity and differed consistently from species of the two annual sections Courtoisia and Collomia by lacking quercetin-5-glucoside and kaempferol-3-arabinosylgalactoside. In contrast, flavonoid patterns among species within sections Courtoisia and Collomia showed a relatively low degree of similarity. The dissimilarity between C. diversifolia and C. heterophylla (section Courtoisia ) is consistent with their divergent patterns of pollen morphology and ecological distribution. Three groups of species within section Collomia were defined generally by shared patterns of flavonoids, which are correlated to some degree with floral, pollen and vegetative morphology.

Ipomopsis sancti-spiritus (Polemoniaceae), a new species from northern New Mexico

Ipomopsis sancti-spiritus, a new species in sect.Ipomopsis, from the mountains of northern New Mexico is described and illustrated. The purplish calyx, pink corolla, and a short pistil with the stigma situated below the included stamens represent a unique combination of characters. The new species is similar toI. arizonica but differs primarily in corolla color and in length of the pistil.

A systematic study of the genus hulsea (Asteraceae)

A systematic treatment based on genetic, biochemical, and morphological studies is presented for the 11 recognized taxa ofHulsea. A uniform diploid complement of 38 chromosomes was found in the 37 populations examined, including all species and representing first reports forH. brevifolia, H. californica, andH. mexicana. Thirteen flavonoid compounds, based on the aglycones quercetin, apigenin, cyanidin, and the 4′-O-methyl ether of luteolin, were detected inHulsea. Patterns of the flavonoid compounds are discussed with respect to the systematic treatment. The results of 595 synthetic crosses indicate thatHulsea species are self-incompatible, relatively cross-compatible, and that their F1 hybrids are relatively fertile. Heterozygosity for one or two translocations is reported for 11 interspecific and intersubspecific hybrid combinations.

Chemical data related to the tribal affinities of Hulsea and Arnica

The taxonomic placement of Hulsea is discussed in light of the distribution of pyrrolizidine alkaloids, sesquiterpene lactones, and polyacetylenic compounds in the Asteraceae.

A new species of thalictrum (Ranunculaceae) from Western Colorado

A new species,Thalictrum heliophilum, from exposed, shale talus of the Green River Formation in western Colorado where it is associated with a number of xerophytic taxa, is described. It differs from the commonT. fendleri by its shorter stature, relatively small, coriaceous, glaucous leaves, and pistillate flowers with 4 or 5 (6) pistils.