Breeding systems and hybridization inPetrorhagia sect.Kohlrauschia (Caryophyllaceae)

In the diploid speciesP. prolifera, the evolution of autogamy has resulted in the presence of distinct selfing and outcrossing races. The change in breeding system toward autogamy is associated with a reduction in the size of floral features and a lower pollen production. The outbreeding populations have only been found in Greece, while the selfing populations have colonized much of Europe. The two races appear to be reproductively isolated from one another. —Petrorhagia sect.Kohlrauschia contains four species.P. glumacea is outbreeding and shows unilateral incompatibility with the small-flowered race ofP. prolifera and interfertility with the large-flowered race; althoughP. glumacea is sympatric with the large-flowered race, they do not appear to hybridize in the wild. Amongst the allopatric species, internal breeding barriers are also found. These may take the form of hybrid sterility or seed incompatibility.P. velutina is autogamous and reproductively isolated from all the other species of the section regardless of whether they are sympatric or allopatric. It is suggested that the evolution of autogamy has been an important factor in the spread ofP. velutina, the tetraploidP. nanteuilii, and the small-flowered race ofP. prolifera in Europe.     

Pollination of the southwestern Opuntias

This paper presents an overview of pollination systems inOpuntia sens. lat. in the southwestern United States. The floral syndrome of large, colorful, bowl-shaped, diurnal flowers is present in all of the prickly-pear species and most of the cholla (Cylindropuntia) species in this area. Pollination by medium-sized and large bees is established for some of the species with this floral syndrome and is predicted for the others. The same floral syndrome is widespread inOpuntia in other geographical areas.—Deviations from this floral syndrome occur in certain species of southwestern chollas, one of which has nocturnal disc-shaped flowers, and in several tropical American species groups or segregate genera with red hummingbird flowers. But such cases are relatively infrequent. Divergence between species with respect to floral syndrome and pollination system is not a common feature in the evolutionary pattern ofOpuntia. Pollination of North American Cacti, IV.—Previons parts of this series:Grant & Grant 1979a,Grant & al. 1979,Grant & Grant 1979b.     

Floral scent and intrafloral scent differentiation inMoneses andPyrola (Pyrolaceae)

Floral scent was collected by headspace methods from intact flowers, petals, and stamens of four species ofPyrolaceae. The scent samples were analyzed by coupled gas chromatography-mass spectrometry (GC-MS). The floral scent inPyrola spp. is differentiated into a characteristic petal scent—phenyl propanoids and a characteristic stamen scent—methoxy benzenes. InMoneses the scent is characterized by isoprenoids and benzenoids, with a larger proportion of benzenoids in the stamens compared to the petals. Specific anther scents may promote foraging efficiency in buzz-pollinated species and enhance flower fidelity. Variation in floral scent composition is consistent with the taxonomic relationships among the genera and species examined.     

Pollination ofOpuntia lindheimeri and related species

The large, yellow, bowl-shaped flowers ofOpuntia lindheimeri, O. discata, O. phaeacantha major, andO. compressa in Texas are visited by various species of beetles and bees. The beetles and small bees (Perdita, Dialictus) are pollen thieves. The pollinators are the medium-sized and larger bees (Melissodes, Diadasia, Lithurge, Megachile, Agapostemon, etc.). Different species of theOpuntia lindheimeri group have the same pollination system and there is no evidence of any floral isolation between them. The pollination system of these species ofOpuntia in Texas is essentially the same as that ofEchinocereus fasciculatus andFerocactus wislizeni in Arizona.Pollination of North American Cacti, II.—SeeGrant & Grant (1979).     

Variation in self-fertility and floral characters ofGeranium caespitosum (Geraniaceae) along an elevational gradient

Characters that have the potential to alter the breeding system ofGeranium caespitosum were investigated. The characters differ mechanistically, functioning either endogenously and independent of pollen transfer, or exogenously by influencing pollen transfer. Little variation in self-fertility (endogenous mechanism) was measured among populations from different elevations grown in a common garden. Variation in floral morphology (exogenous mechanism) was limited and unlikely to create a change in the breeding system. Macroscopic variation (exogenous mechanism), including gynodioecy, sexual specialization, and pollen sterility, was observed in extreme elevation populations and probably has a sizeable effect on the breeding system.     

Contrasting breeding systems in twoEriotheca (Bombacaceae) species of the Brazilian cerrados

The pollination biology and breeding systems ofEriotheca pubescens andE. gracilipes have been studied. These two species occur as trees in cerrado vegetation, the neotropical savannas of Central Brazil, with partially sympatric distributions. They have similar phenology and floral structure, although the flowers ofE. pubescens are larger. Both species have nectar flowers pollinated by largeAnthophoridae bees but the main pollinators of each species differ in size. The species have markedly different breeding systems: late-acting self-incompatibility inE. gracilipes and apomixis stimulated by pollination inE. pubescens.     

Patterns of genetic variation of the genusCapsicum (Solanaceae) in Mexico

The evolutionary relationships of 186 accessions ofCapsicum from Mexico were studied through enzyme electrophoresis. A total of 76 alleles representing 20 genetic loci coding for nine enzyme systems were observed and the allelic variations of enzymes were studied for geographical distribution. Allele frequencies were used to estimate the apportionment of gene diversity within and between populations and to construct a dendrogram based on a similarity matrix containingNei genetic distances. — The gene diversity estimates suggest that the structure ofCapsicum populations in Mexico consists of predominantly homozygous genotypes presumably due to a self-pollinated breeding system and population bottlenecks. Significant genetic differentiation was found mainly between populations of differing geographical regions.—Based on the results of this study, three species of domesticatedCapsicum can be identified in Mexico,C. annuum var.annuum, C. chinense, andC. pubescens. Semidomesticated and wild forms include two species,C. frutescens andC. annuum var.glabriusculum. A sharp geographical division results between the latter species;C. frutescens was collected exclusively in the southeastern states of Oaxaca, Chiapas, and Tabasco; whereas wild and semidomesticated forms from the rest of the country areC. annuum. Based upon the similarity of enzyme genotypes of semidomesticated and wild forms, the primary center of domestication of cultivatedC. annuum was estimated to be the region comprising the states of Tamaulipas, Nuevo Leon, San Luis Potosi, Veracruz, and Hidalgo in eastern Mexico. A possible second center of domestication is suggested to be localized in the state of Nayarit, western Mexico.     

Floral scent chemistry and pollination ecology in phytelephantoid palms (Arecaceae)

The subfamilyPhytelephantoideae comprises three genera (Ammandra, Aphandra, andPhytelephas) and seven species of dioecious palms. The floral scents ofAmmandra dasyneura, A. decasperma, Aphandra natalia, Phytelephas aequatorialis, P. macrocarpa, andP. seemannii were analyzed by gas chromatography-mass spectrometry. We studied the pollination biology ofA. natalia, P. aequatorialis, andP. macrocarpa, and tested how the synthetically produced main constituents of the floral scents ofAphandra andPhytelephas attracted insects in two natural populations ofPhytelephas. The genera are distinct in terms of floral scents.Ammandra has sesquiterpenes,Aphandra (+)-2-methoxy-3-sec-butylpyrazine, andPhytelephas p-methyl anisol. These constituents dominated the scents quantitatively and qualitatively. The similarity between scents of male and female inflorescences was 76.5% inAmmandra, 84.2% inAphandra, and >99% inPhytelephas. Different species ofAleocharinae (Staphylinidae) pollinateAphandra natalia andPhytelephas species and reproduce in their male inflorescences.Derelomini (Curculinoidae) andMystrops (Nitidulidae) only visit and pollinatePhytelephas in which male inflorescences they reproduce. A species ofBaridinae (Curculionidae) only visits and pollinatesAphandra natalia, and reproduces in its female inflorescence. The apparent reliance on one or a few floral scent constituents as attractants and few and specific pollinators may indicate co-evolution. Sympatric species ofPhytelephantoideae have different scents. We suggest that species with similar scents have allopatric distributions due to the absence of a pollinator isolation mechanism.     

Floral bract function, flowering process and breeding systems ofSarcandra andChloranthus (Chloranthaceae)

Structure and function of floral bracts, anthesis and breeding systems were investigated in greenhouse plants ofSarcandra chloranthoides, Sarcandra glabra, andChloranthus spicatus (Chloranthaceae). In early developmental stages the floral bract replaces the lacking perianth as a protective structure by enclosing the floral organs completely in a pocket-like structure, which is formed by the u-shaped attachment zone of the floral bract to the spike axis. The floral bract has a tip with an epithem tissue, from which traces of secretion seem to be released by the stomata. All species investigated have protogynous and longlasting flowers. The female phase begins five to seven days earlier than the male phase. It continues during the male phase and for some time thereafter. The male phase lasts between one day (Chloranthus spicatus) and seven days (Sarcandra chloranthoides). This is the first study on breeding systems of Chloranthaceae. They are of special interest in such a basal family of the angiosperms. Although the investigatedSarcandra andChloranthus species have similar flowers with entomophilous features, surprisingly their breeding systems are diverse:Sarcandra glabra is self-compatible,S. chloranthoides is agamospermous andChloranthus spicatus is self-incompatible.     

Flower variation and breeding systems in theCistaceae

Fourteen common southern Spanish species in theCistaceae were examined for quantitative variations in floral traits. These included the diameter of the corolla, number and size of anthers, number of ovules, and the size and shape of the gynoecium. The variables were in most instances positively correlated, species with larger flowers having more and larger anthers, more ovules, etc. Shrubs were observed to possess the largest, annuals the smallest, and subshrubs medium-sized flowers. Detailed observations of flower structure and function in a shrub (Cistus salvifolius), a spring-annual (Tuberaria guttata) and a winter-annual (T. inconspicua), revealed substantial variations in the breeding system. WhileC. salvifolius (and probably most woody species in this family) presents self-incompatibility, annual species ofTuberaria are self-compatible. In the studied population,T. inconspicua plants bore only reduced, cleistogamous flowers with no sign of a corolla.T. guttata has chasmogamous flowers that can facultatively self-pollinate.     

Asphodelus tenuifolius andA. fistulosus (Liliaceae) are morphologically,genetically, and biologically different species

The biological analysis of six populations ofAsphodelus tenuifolius and 12 populations ofA. fistulosus has confirmed that they are separate species. Both their floral structures (length of the tepals, stamens, anthers and style) and also their pollen size are clearly different.A. tenuifolius has only the 2n = 28 chromosome race, whileA. fistulosus has 2n = 28 and 2n = 56.A. tenuifolius is genetically less variable thanA. fistulosus and they have different electrophoretic mobilities. Gene duplication phenomena exist in the 2n = 28 level of both species.     

AFLP and breeding system studies indicate vicariance origin for scattered populations and enigmatic low fecundity in the Moroccan endemic Hypochaeris angustifolia (Asteraceae), sister taxon to all of the South American Hypochaeris species

We used Amplified Fragment Length Polymorphism markers (AFLP) and breeding system studies to investigate the population structure and reproductive biology of Hypochaeris angustifolia (Asteraceae: Cichorieae). This species is endemic to altiplanos of the Atlas Mountains (Morocco) where it occurs in scattered populations, and it is the sister species to c. 40 species of this genus in South America. PCoA, NJ, and Bayesian clustering, revealed that the populations are very isolated whilst AFLP parameters show that almost all populations have marked genetic divergence. We contend that these features are more in accord with a vicariance origin for the scattered populations of H. angustifolia, rather than establishment by long-distance dispersal. The breeding system studies revealed that H. angustifolia is a self-incompatible species, with low fecundity in natural and in experimental crosses, probably due to a low frequency of compatible phenotypes within and between the populations.     

Erhaltung und Wiederansiedlung des Kleinen Rohrkolbens (Typha minima) – Vegetationsaufnahmen, Monitoring und genetische Herkunftsanalysen

Galeuchet D. J. and Holderegger R. 2005. Conservation and re-introduction of Dwarf Bulrush (Typha minima) – vegetation surveys, monitoring and genetic analysis of origin. Bot. Helv. 115: 15–32.Typha minima was formerly widespread along fast flowing alpine rivers but is now red-listed as critically endangered. To assess its conservation perspectives, we surveyed the few remaining natural populations along the alpine part of the River Rhine from 1997 to 2002 and determined their genetic diversity using isozyme electrophoresis. Six of the populations became extinct or extremely small, probably due to shading by taller plants and trampling, while six other populations remained stable or increased, partly due to habitat restoration measures. The largest populations, with areas of more than 10000 m², are found in secondary habitats which are regularly disturbed due to water regime management. Of the 19 investigated isozyme loci, only six were polymorphic. Allelic diversity (1.4–1.8) was low in all populations, and the number of multilocus genotpyes (1–18) was low for 11 of 13 investigated populations. Genetic diversity was also studied for ex-situ cultivations of T. minima in Swiss botanical gardens and reintroduced stands.These artificial populations (each with 1–3 multilocus genotypes) were genetically similar to natural populations (average genetic distance 0.094). For two ex-situ cultivations with unknown origin, the likely origin could genetically be defined. Hybridisation between two ex-situ cultivations of different origin (i.e. a potential risk of genetic introgression) was detected in one botanical garden. It is concluded that the long-term conservation of T. minima requires both the restoration of regularly disturbed, sparsely vegetated river margins and the re-introduction of plants from ex-situ cultivations with appropriate origin.Manuskript angenommen am 2. Februar 2005     

Pollination ofDianthus gratianopolitanus (Caryophyllaceae)

Pollination ofDianthus gratianopolitanus was studied in a population of the Swiss Jura mountains. Pollinators of this plant species are reported here for the first time. The flowers were not only visited by butterflies as postulated in the literature, but also by diurnal hawkmoths (Macroglossum stellatarum) and by diurnal and nocturnal noctuid moths. — Nectar is sucrose-dominant, the sugar concentration is moderate but the amino acid concentration is high. Nectar characteristics correspond well with the syndrome ofLepidoptera-pollinated flowers. — Field observations and flower characters (colour, range of the calyx length) suggest thatDianthus gratianopolitanus is an intermediate species in the transition of butterfly to moth pollination. — Lack of reproductive success inDianthus gratianopolitanus can not be attributed to lack of suitable pollinators.     

Stylar trimorphism in four functionally andromonoeciousProsopis species (Mimosaceae)

The reproductive system ofProsopis chilensis, P. pugionata, P. flexuosa, andP. torquata is described. Observations were made of floral morphology, stigmatic receptivity, pollen grain viability, and the nature of pollen reserves. Scanning electrone microscopy and statistical analysis were carried out. The results allow us to conclude that: 1) The studied species have three distinct floral morphs characterized by significantly different style lengths and, to a lesser extent, different stamen lengths; 2) style precocity found in all species does not indicate protogyny; 3) flowers with shortest styles are not receptive; 4) the pollen grains of all floral morphs showed high viability; 5) peroxidase is present in both the pollen and pistil; 6) viable pollen grains invariably have both starch and pollenkitt; 7) the studied species are andromonoecious.     

异质生境对二型花柱植物雪地报春花性状分化的影响

该研究以生长在新疆北部的二型花柱植物雪地报春(Primula nivalis)为研究材料,对7个低海拔(1 657~2 013m)森林居群和7个高海拔(2 400~2 700m)草原居群的花型比例进行调查,对花部特征进行检测,并对长、短花柱植株在不同海拔居群的花性状分化进行了比较研究,以揭示该类群植物的演化与环境的关系。结果表明:(1)在高海拔草原居群中长花柱植株比例高于短花柱植株。(2)比较草原和森林生态系统中的雪地报春居群,长花柱花形态特征间存在显著差异,但短花柱花形态特征间的差异不显著。(3)高海拔草原居群中长花柱花的花冠筒长度、雄蕊长度、雌雄蕊距离、雌雄异位程度以及雌雄蕊空间位置是导致花性状分化的主要因素。(4)在草原居群中,长花柱花的雄蕊、雌雄异位程度及花冠口至雄蕊距离的变化减少了长短花柱花间的互补式对应性。研究认为,在异质生境中长花柱花性状的变化是导致该物种长短花柱花性状分化的主要因素。     

Genetic variation and population structure in Korean endemic species: III.Hosta minor (Liliaceae)

Hosta minor, an insect-pollinated and rhizomatous herbaceous perennial, occurs in eastern and southern Korean Peninsula. AlthoughH. minor is a Korean endemic species and most populations of the species are scattered, the species maintains considerably high levels of genetic variation within the species, with a moderate level of variation (14%) found among populations. Nineteen of the 29 putative loci resolved (66%) were polymorphic within the species, the mean number of alleles per locus was 2.10 across all populations and averaged 1.68 within populations. In addition, genetic diversity was a considerably higher (for species and population level, mean estimates of genetic diversity were 0.275 and 0.230, respectively) than the average for other long-lived herbaceous perennials. Indirect estimate of the number of migrants per generation (Nm=1.03, calculated from mean G_ST) was moderate. Factors contributing to the high levels of genetic diversity found within populations ofH. minor include population maintenance via sexual and asexual modes of reproduction, primarily outcrossing breeding system, long generation time, probable ancient polyploid origin of the species, and moderate levels of seed dispersal by wind. Human disturbance in South Korea such as road and apartment constructions appears to be the major threat to this genetically diverse species.     

Fruit dimorphism inPhaseolus sublobatus (Fabaceae) and its evolutionary significance

Populations of the annualPhaseolus sublobatus from different ecogeographical zones are genetically differentiated. In twelve populations from the western ghats (Maharashtra range) chasmogamous flowers are arranged in peduncled capitate racemes borne in leaf axils of higher nodes. One population (Poona Race S₄) has additional inflorescences, also with chasmogamous flowers, on the main axis between the cotyledonary node and the ground. When the pods of these flowers ripen, the inflorescence gradually coils and, eventually, gets bury the fruits in the soil. This phenomenon is not known in any other plant.—The seed-coat patterns as revealed by SEM, and germination behaviour of both aerial and subterranean seeds are similar, and both types of seeds lack dormancy.—Heavy seed predation selection pressure is probably the principal cause for the evolution of fruit dimorphism inP. sublobatus. The origin of geocarpy in relation to fruit dimorphism and seed predation is discussed.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Floral biological observations onHeliamphora tatei (Sarraceniaceae) and other plants from Cerro de la Neblina in Venezuela

During 20 days in 1985, floral biological observations were made at 1 850–2 100m elevation on Cerro de la Neblina in Venezuela.Heliamphora tatei var.neblinae (Sarraceniaceae) is nectarless and has poricidal anthers.Heliamphora tatei, Graffenrieda fruticosa, G. polymera, G. reticulata, Tocca pachystachya, T. tepuiensis (Melastomataceae),Saxofridericia compressa, andStegolepsis neblinensis (Rapateaceae), are buzz-pollinated by ten species ofBombus, Eulaema, Melipona, Centris, Xylocopa, Dialictus, andNeocorynura. Additional observations of floral visits on tepui species ofGentianaceae, Loranthaceae, Malpighiaceae, Ericaceae, Orchidaceae, andAsteraceae are reported. Visitors include the hummingbirdCampylopterus duidae, the flower-piercerDiglossa duidae, the nectarivorous batAnoura geoffroyi, and various species ofCentris andBombus bees. Scent baits for euglossine bees attracted very few bees.Apis mellifera adansonii-scutellata, the africanized honey bee, was caught at 1 850m elevation.