Robert Ornduff

Goldfields Revisited: A Molecular Phylogenetic Perspective on the Evolution of Lasthenia (Compositae: Heliantheae sensu lato)

DNA sequence data from the internal and external transcribed spacers of 18S‐26S nuclear ribosomal DNA and the 3′ trnK intron of chloroplast DNA provide evidence for patterns of evolutionary diversification and relationships in Lasthenia. Maximum parsimony analysis shows strong support for monophyly of Lasthenia and monophyly of each of seven sections (as treated here) in Lasthenia, with minor revision of Ornduff’s (1966) sectional circumscriptions. Lasthenia sect. Amphiachaenia (correct name for L. sect. Baeria sensu Ornduff 1966 and redelimited to include L. leptalea) was resolved as a basally divergent section, i.e., as the sister group of a clade comprising all other Lasthenia taxa. Placement of other sections within Lasthenia is only weakly resolved, except for L. sect. Burrielia (redefined to exclude L. leptalea) and L. sect. Hologymne, which are robust sister clades. The clade comprising L. sect. Burrielia and L. sect. Hologymne and clades corresponding to each of the other sections except L. sect. Amphiachaenia constitute a polytomy, with most clades characterized by a long basal branch and relatively short terminal branches. We suggest that overall patterns of divergence in the molecular trees for Lasthenia conform to expectations of saltational diversification, with an initial rapid radiation followed by long periods of minimal diversification in each group preceding relatively recent episodes of speciation. Results also show that several important taxonomic characters in Lasthenia are homoplastic and that the base chromosome number for Lasthenia is x=8.

Pollen flow inPrimula veris (Primulaceae)

Observations on two natural and one artificial distylous populations ofPrimula veris in Britain revealed very high proportions of intramorph pollen on pin stigmas and moderate proportions of intermorph pollen on thrum stigmas. The average ratio of pin: thrum pollen production per flower was 2.4:1. Large amounts of pollen remained in dehisced anthers, perhaps reflecting low levels of pollinator activity. Population size and density had no clear effect on pollen flow patterns, which are asymmetrical for the two morphs.

The genetics of heterostyly in Hypericum aegypticum

Hypericum aegypticum L. (Hypericaceae) is a shrubby distylous species of north-western Africa and a few Mediterranean islands. It and two other species constitute section Adenotrias, the only section of a large genus of c. 400 species in which heterostyly is known to occur (Ornduff, 1975). In the few families for which the genetics of distyly has been worked out, there is a one-locus two-allele system that governs the trait. The long-styled (pin) flowers are produced by the homozygous recessive genotype (ss) and the short-styled (thrum) flowers are produced by the heterozygous genotype (Ss, or occasionally SS in some self-compatible species). A selfing and crossing programme was carried out using three pin and four thrum plants of H. aegypticum collected in the mountains c. 19 km northwest of Agadir on the Atlantic coast of Morocco. Because of a slight selfcompatibility of both morphs, a few seeds were obtainable from each cross (table). All progenies of the crosses thrum x thrum or of thrum selfed were composed of thrum individuals (table). All pin x pin crosses or pin selfs produced progenies with pins and thrums. Although the proportion of pins to thrums varied from progeny to progeny, when considered collectively, the ratio of pins: thrums in the F1 was 3: 1 (table). Thus, for Hypericum aegypticum pins are Ss and thrums are ss. The genetic basis of distyly has been determined for several species of Primula (Primulaceae; e.g. Bateson and Gregory, 1905; Mather, 1950; see

Flavonoids of Lasthenia conjugens and Lasthenia fremontii

Abstract The flavonoid complement of Lasthenia conjugens and L. fremontii (Compositae) as well as hybrids derived from these two species has been determined. The compounds observed were: quercetin-3- O -glucoside, quercetin-3- O -glucuronide, patuletin-3- O -glucoside, patuletin-3- O -glucuronide, patuletin-7-potassium bisulfate, patuletin-3, 7-di- O -glucoside, patuletin-3- O -glucoside-7-potassium bisulfate, and a quercetin-3- O -bioside. This latter compound was present in very small concentration in the hybrids only and yielded glucose and glucuronic acid. The hybrids lacked patuletin-7-potassium bisulfate.

Flavonoids of artificial interspecific hybrids in Lasthenia

Abstract The flavonoids of artificial interspecific hybrids in Lasthenia indicate differences in inheritance patterns among various classes of these compounds. Inheritance of production of anthochlors, kaempferol, and some patuletin glycosides is additive. Inheritance of production of luteolin and quercetin glycosides is not always additive, and in some progenies quercetin glycosides are produced that do not occur in the parents.

Ecology, morphology, and systematics of jepsonia (Saxifragaceae)

Aspects of flowering, leaf production, caudex and contractile root morphology, edaphic preferences, and systematics ofJepsonia (Saxifragaceae) are discussed. Although other authors have recognized as few as one species ofJepsonia, various lines of evidence suggest that three allopatric species can be recognized, which are morphologically distinct and separated from each other by barriers to hybridization. These species areJ. heterandra of the Sierra Nevada foothills of California,J. malvifolia of southern California’s offshore islands and the Mexican Guadalupe Island, andJ. parryi of mainland southern California and adjacent Baja California. Plants flower from late summer to early winter in response to environmental factors that have yet to be clearly identified. Flowers are heterostylous, and the species are self-incompatible. Pollination is by syrphid flies and halictid bees. Leaves are produced during or after flowering in response to rain. They persist through the winter until the onset of the dry season in the subsequent late spring. Plants perennate by a starchy underground structure, which is hypocotylar in origin and best termed a caudex. Young plants and many old ones also produce one or more very large, whitish, starch-free contractile roots that are annual in duration.Jepsonia heterandra characteristically is restricted to the crevices of slatelike rocks, although the other two species occur in a wider range of edaphic situations. Moisture and temperature conditions, as well as rodent predations, may determine the general and local distribution of the species. The relationships of the genus are briefly considered, and interspecific differences are described.

Stigma morphology in distylous and non-heterostylous species ofVillarsia (Menyanthaceae)

Stigma morphology was examined with the SEM in 14 of the 16 species ofVillarsia. In nine of the ten distylous species studied, stigmas of the floral morphs were strongly dimorphic in length, shape, configuration of the receptive surface, and in the size and density of their papillae. Thrum stigmas ofVillarsia, in contrast to those of most other distylous species, are not simply smaller versions of the conspecific pin stigmas, but generally exhibit an array of morph-specific characters. Thrum stigma lobes may be broader than those of pins, they may have undulate margins, lobes subdivided into secondary lobes, papillae more extensively distributed than in pins, and various combinations of these traits occur. The traits that distinguish thrum from pin stigmas achieve an increase in the receptive area and may enhance more efficient pollen capture by the shorter and less accessible thrum stigmas. The morphogenesis of the stigma shape dimorphism appears to involve processes more complex than inhibition of elongation in thrum styles. InVillarsia, the stigma dimorphisms are species-specific. No correlations were found between morphologies of the stigma and the different breeding systems in distylous species. Stigmas of the four non-heterostylous species examined resemble the thrum stigma type found in most distylousVillarsia species.

Flavonoid races in lasthenia (Compositae)

Nine of the 13 taxa ofLasthenia in which two or more populations were examined for flavonoid constituents exhibited interpopulation variation in these constituents. In certain species entire classes of compounds were present in some races and absent from others. Some of these biochemical differences are due to the failure of certain steps to occur in the biosynthesis of various flavonoids from precursor compounds. Another pattern of variation involves intraspecific differences in the nature of flavonoid glycosides that are produced. In view of the close biosynthetic relationships among all the flavonoids produced byLasthenia, the genetic differences among the flavonoid races of a species may be small. Whether or not these biochemical differences have any adaptive significance is problematical at present.

Hybridization and regional variation in Pacific Northwestern Impatiens (Balsaminaceae)

Variation patterns ofImpatiens species in the Pacific Northwest are discussed. Much of the variability there is attributed to widespread interspecific hybridization. Taxonomy of the genus is briefly reviewed, and it is suggested that four species should be recognized for the region. An account of natural hybridization betweenI. capensis andI. ecalcarata is given in detail, and it is postulated that the effects of this hybridization may extend beyond the immediate area in which it is detectable on the basis of morphological patterns. It is suggested thatI. aurella may be of hybrid origin since it combines characters of two species in the Pacific Northwest. Although natural hybridization is occurring at the present time, geographical distribution of variant populations of the species suggests that extensive hybridization may have been initiated in late Pleistocene as a result of the ecological disturbances prevalent at that time.

Chromosome numbers of Western Australian species ofVillarsia (Menyanthaceae)

Chromosome numbers are reported for eight of the nine Western AustralianVillarsia species.Villarsia albiflora, V. calthifolia, V. capitata, V. congestiflora, V. lasiosperma, V. latifolia, andV. violifolia are diploid with n=9. Five populations ofV. parnassiifolia are diploid and three are tetraploid (n=18). The morphological, ecological, and breeding-system diversity of the Western Australian species is largely not associated with the tetraploidy or hexaploidy that characterizes otherVillarsia species in eastern Australia and South Africa. The majority of Western AustralianVillarsia species are restricted to the high rainfall zone of southwestern Western Australia, where favorable climatic and edaphic conditions may have existed since mid-late Tertiary times.