Floral rewards in someScrophularia species (Scrophulariaceae) from the Iberian Peninsula and the Balearic Islands

The genusScrophularia in the Iberian Peninsula and Balearic Islands comprises two sections,Scrophularia andCaninaG. Don. Analyses were carried out on flower production, flower duration and their sexual phases, pollen and nectar production together with observations on their pollinators. Nectar production is correlated with corolla size and pollen production with anther size. The taxa of sect.Scrophularia show greater nectar and pollen production than those of sect.Canina. Also, those of the first section produce more ovules per ovary than those of the second group, production being correlated with the ovary size.Some observations on floral and reproductive biology in some species ofScrophularia from the Iberian Peninsula and the Balearic Islands. I.     

DNA fingerprint variation in some blackberry species (Rubus subg.Rubus,Rosaceae)

We have analysed samples from Sweden, Denmark, and Germany of six facultatively apomictic blackberry species to investigate the accordance between a taxonomy based on morphological characters on the one hand, and distribution of genetic variation estimated by DNA fingerprinting on the other hand. DNA fingerprint variation was found to be quite restricted in all species investigated. The first taxonomic group included three species related toRubus nessensis, two being characterized by one very widespread DNA fingerprint in all three countries and a few rare ones, whereas the third species differed between Sweden and Germany. The second taxonomic group included species related toR. gracilis. Two of these species exhibited very similar DNA fingerprints, whereas the third species deviated clearly. The utilization of DNA fingerprinting as a tool in taxonomy is discussed; most likely this method could become a useful complement to morphology, especially in plant groups with reduced levels of genetic recombination.     

Multivariate and cladistic analyses of the purple-flowered species ofErysimum (Cruciferae) from the Iberian Peninsula

A taxonomically difficult purple-flowered group within the genusErysimum, restricted to the Iberian Peninsula, is analyzed by multivariate and cladistic analyses. 51 specimens have been scored for 14 characters. Both principal components and discriminant analyses provide support to the recognition of the five species considered by the author, namelyE. linifolium, E. lagascae, E. baeticum, E. popovii, andE. cazorlense. Cladistic analysis, using 7 characters resulted in a single most parsimonious cladogram containing no homoplasies. The pattern of morphologic divergence follows a clear NW.-SE. trend, which is congruent with the topology of the cladogram. This trend significantly affects growth-form as well as fruit characters, both providing the main grounds for species recognition. The different behavior and significance of several characters in both kinds of analysis is discussed. The co-occurrence of morphologically similar individuals differing in the flower color is discussed, too. Possible explanations for this phenomenon involve hybridization in a wide sense or, alternatively, rejecting the assumption of monophyly for the group.     

Reproductive biology ofAsphodelus aestivus (Asphodelaceae)

InAsphodelus aestivus the large number of showy flowers opened per inflorescence, high nectar and pollen production, and absence of automatic self-pollination, so that insect visitation is necessary for pollination, indicate that cross-fertilization is favoured. LargeHymenoptera are the main pollinators. Hand self-pollinations result in some degree of fruit-set, but cross-pollination also yield low fruit- and seed-set. The perennial habit and polyploid status are in agreement with the breeding system of this species, with sexual reproduction being rather inefficient and active vegetative propagation.     

Karyology of theScorzonera (Compositae) species from the Iberian Peninsula

A karyological study of 15 taxa ofScorzonera L. from the Iberian Peninsula has been made. The chromosome numbers found inS. hispanica var.pinnatifida, S. baetica, S. reverchonii, S. angustifolia, S. laciniata var.calcitrapifolia and var.subulata (2n = 14) are new. Diploid cytotypes with 2n = 14 and 2n = 12 prevail, andS. hispanica var.crispatula is the only taxon which exhibits autopolyploidy (2n = 14, 28). x = 7 is considered to be the base chromosome number within the genus, with x = 6 being derived from it by translocation. This and detailed karyotype analyses allow to group the Iberian Peninsula species ofScorzonera into three groups.     

Comparisons of within-population genetic variation in sexual and agamospermousAmelanchier (Rosaceae) using RAPD markers

We compared genetic variation of sexualAmelanchier bartramiana and facultatively agamospermous (asexually seed-producing)A. laevis at one site where the two species are sympatric. We analyzed 77 random amplified polymorphic DNA (RAPD) markers in 29A. bartramiana individuals and 76 RAPD markers in 31A. laevis individuals. The two species do not differ significantly in mean genetic variation. However, 22.4% of genetic similarity values betweenA. laevis individuals exceed the highest value ofA. bartramiana and may represent the effect of agamospermy. Variation withinA. laevis may be the result of sexuality, hybridization, polyploidy, and other factors.     

Sexual reproduction in someScrophularia species (Scrophulariaceae) from the Iberian Peninsula and the Balearic Islands

The reproductive biology of someScrophularia species in the Iberian Peninsula and Balearic Islands has been studied. Levels of fruit-set in bagged and unbagged inflorescences, the production of seeds/capsule, the effectiveness of seed-set following cross-pollination in the genus and the pollen/ovule ratios have been analyzed.Some observations on floral and reproductive biology in some species ofScrophularia from the Iberian Peninsula and Balearic Islands. II. For first part seeOrtega Olivencia & Devesa 1993.     

Different levels of morphometric variation in three heterogamous dogrose species (Rosa sect.Caninae, Rosaceae)

Difficulties in delimiting well-defined entities in the dogroses (Rosa sect.Caninae) has resulted in very variable taxonomic treatments. The present study was undertaken to provide a background for taxonomy as well as plant breeding. Morphometric diversity was analysed on seedlings obtained from field collections in South Sweden of three species,Rosa dumalis, R. rubiginosa andR. villosa. A canonical variates analysis showed that the three species are relatively distinct whereas two subspecies ofR. dumalis were less well discriminated. Analyses of variance demonstrated that intraspecific variation is pronounced inR. dumalis and, to a lesser extent, inR. villosa.     

Reproductive biology in the primitive relic AngiospermDrimys brasiliensis (Winteraceae)

From field observations onDrimys brasiliensis, principally in the Botucatu region of São Paulo State, Brazil, new data on the reproductive biology, the rhythm of growth, and the development of lateral cymose inflorescences, flowers and fruits are presented. Pollination accelerates the rate of flower-development for about 4–6 days. Pollination experiments show thatD. brasiliensis is not self-sterile; because of mechanical devices the sticky pollen grains do not normally come into contact with the stigmata unless an animal pollen vector is involved. The pollinators are diurnalColeoptera, Diptera andThysanoptera which eat from the pollen, lick from the stigmatic exudates and (in case of the flies) probably also from the staminal glands. Fruit- and seedeaters are birds which seem to be the main dispersal agents. Establishment of new individuals normally is through seedlings, but also by vegetative propagation through plagiotropous branches which may root and separate from the mother plant. The morphological, developmental and reproductive aspects inD. brasiliensis are discussed in a wider context, compared with data from otherMagnoliidae, and related to aspects of early Angiosperm evolution.     

Reproductive biology of the Andean-disjunct genusRetanilla (Rhamnaceae)

Various aspects of the reproductive biology of the Andean-disjunct genusRetanilla (DC.) Brongn. were studied in populations ofR. trinervia andR. ephedra located in central Chile and ofR. patagonica in southern Argentina. Flowering extends from -austral- winter (early spring inR. patagonica) to early summer. The small, white, entomophilous flowers are incompletely protandrous and last four to five days. A weak pleasant odor along with nectar and pollen attract thirty-seven diurnal insect species, ten of which are probable pollinators: these include the honey bee, eight species of solitary bees pertaining toAnthophoridae (1 sp.),Colletidae (3 spp.) andHalictidae (4 spp.), and a nemestrinid fly. Although flower morphology and individual flower phenology do not fully prevent self-pollination (and geitonogamy can easily take place), the level of autogamy is low. Therefore, some self-incompatibility mechanism seems operative inRetanilla. Fruit set of open-pollinated flowers is extremely low, with a maximal value of c. 3% inR. patagonica. In this species, ripe fruits contain on average 1.37 viable seeds. Predispersal (maternal) reproductive success (percent ovules becoming viable seeds) is 2.3%. For medium to full-sized individuals this corresponds to c. 4600 potential offspring per year. As presently known,Retanilla is a reproductively uniform group, in which the Andean disjunction seems to have exerted no particular impact, which is consistent with the view that pollination generalization exerts some stabilizing influence on floral morphology and other reproductive traits.Retanilla expresses a basic rhamnacean set of traits (including protandry and self-incompatibility) showing also high pollen production and secondary pollen presentation. The latter two traits seem characteristic of theRetanilla-Trevoa clade, suggesting that a trend to increased male effort and, perhaps, dependence upon polleneating has evolved within the tribe Colletieae.     

Reproductive biology of the melon cactus, Melocactus curvispinus (Cactaceae)

We examined the reproductive biology of Melocactus curvispinus Pfeiffer (Cereeae, Cactoideae) in xeric areas of northern Venezuela. Floral traits correspond to a classic hummingbird-pollination syndrome; however, pollination is shared between hummingbirds, Leucippus fallax (Bourcier 1843), and anthophorid bees, Ceratina sp. Reproduction occurs during most of the year. Anthesis and nectar secretion occur between noon and sunset. Average daily nectar production per flower was 163.1 l, nectar sugar concentration between 29.1 and 30.2% (w/w). Hummingbirds promoted inter-plant pollen movement and were relatively more reliable floral visitors than anthophorid bees, but these insects had a higher frequency of floral visits (28.75/day) than hummingbirds (4.96/day). M. curvispinus is self-compatible and autogamous. By combining extended reproductive activity, frequent animal-mediated pollination, and selfing capabilities, this cactus possesses a mating strategy that guarantees reproduction under variable environmental conditions. We argue that based on its reproductive biology, M. curvispinus should be considered an example of evolutionary transition towards selfing within tribe Cereeae.     

Chromosome numbers of European blackberries (Rubus subg.Rubus,Rosaceae)

Chromosome numbers are presented for 32 collections of 29 European blackberry species (Rubus subg.Rubus) from Germany. One species is triploid (2n = 21), 27 species are tetraploid, (2n = 28), and one species is pentaploid (2n = 35). Chromosome numbers are reported for the first time ofR. adspersus, R. amisiensis, R. calvus, R. conothyrsoides, R. contractipes, R. demissus, R. elegantispinosus, R. ferocior, R. foliosus, R. hypomalacus, R. leucandrus, R. nemorosus, R. platyacanthus, R. praecox, R. rhombifolius, andR. rhytidophyllus. Chromosome numbers forR. dasyphyllus, R. gelertii, R. glandithyrsos, R. lamprocaulos, R. lindebergii, R. macrophyllus, R. montanus, R. muenteri, R. pedemontanus, R. polyanthemus, R. senticosus, R. silvaticus, andR. vigorosus are confirmed.     

Reproductive biology of two tree species of Leguminosae in a Montane Rain Forest in southeastern Brazil

Studies on sympatric species that belong to the same taxonomic group and have the same pattern of pollination and seed dispersion, but different patterns of geographical distribution and structural parameters may be worthwhile to understand the evolution of their compatibility system. We studied the floral biology, pollinators and reproductive systems of two tree species in Itatiaia, an area covered with montane rain forest. Pseudopiptadenia contorta is widespread in Brazil but is present at a low relative density at the study site, while Pseudopiptadenia leptostachya is restrictively distributed but presents one of its highest relative density values in Itatiaia. Both species have small flowers arranged in compact spicate raceme inflorescences that constitute the pollination unit. Pollinators are native stingless bees and European honeybees that collect pollen from their nectarless flowers. Although both species have similar floral characteristics and pollination system, their compatibility system differs. Fruit set after manual pollinations and observation of the pollen tube growth showed that P. leptostachya is self-compatible while P. contorta only set fruits after cross-pollinations, and is thus a self-incompatible species. However, fruit set did not differ between the species, indicating that structural parameters are not affected by the compatibility system. Thus, the difference between these two species in terms of reproductive system may be related to other factors such as patterns of geographical distribution.     

Honeyeater (Meliphagidae) pollination and the floral biology of PolynesianHeliconia (Heliconiaceae)

The primary pollinator of Polynesian heliconias,Heliconia laufao andH. paka, is the Wattled Honeyeater,Foulehaio carunculata. This report is the first documentation of pollination by honeyeaters in the genusHeliconia and the first record ofF. carunculata as a pollinator of a plant species. The Polynesian heliconias bear inflorescences that produce 2–4 hermaphroditic flowers per day for a period of 2–3 months. Each flower secretes abundant nectar (125–184 l) with low sugar concentration (15–18% sucrose-equivalents, weight per weight basis) which is available at anthesis just before dawn. Ninety percent of flower visits occur between anthesis and mid-morning. The honeyeaters perch on inflorescence bracts, and probing of the flower results in pollen deposition on the head and bill from where pollen is transferred between flowers. No statements on compatibility can be made forHeliconia paka; however,Heliconia laufao appears to be self-compatible. Calculations of energetic values of nectar of the Polynesian heliconias and Daily Energy Expenditures ofF. carunculata suggest that populations ofH. laufao andH. paka serve as rich energy resources for their pollinators.     

Reproductive biology of a primitive angiosperm,Pseudowintera colorata (Winteraceae), and the evolution of pollination systems in theAnthophyta

Stigmatic exudate-eating chironomid flies (Smittia) and pollen-eating halodid beetles are the most common visitors to flowers ofPseudowintera colorata. Plants are self-incompatible. After selfing pollen tubes penetrate the nucellus; chase pollination experiments show that the incompatibility reaction occurs before fertilization. When pollen is applied to stigmas, the exudate dries rapidly and does not usually reappear. A review of anthophytes suggests that their common ancestor around 200 mya was bisexual and pollinated at least in part by nectar-seeking insects, possibly including flies. The angiosperm stigma appears to have evolved from a pollination drop mechanism via an adaxial stigmatic surface.Dedicated with pleasure to ProfessorW. R. Philipson on the occasion of his 80th birthday.     

Genetic diversity inChaenomeles (Rosaceae) revealed by RAPD analysis

Genetic relatedness inChaenomeles was studied by RAPD analysis in 42 plants representing accessions of three wild species and one hybrid taxon. Amplification with 17 primers yielded a total of 156 polymorphic RAPD bands. Estimates of genetic relatedness suggest thatC. cathayensis andC. japonica are the most distantly related species, and that the former is comparatively homogeneous.Chaenomeles speciosa, which may have arisen through hybridization betweenC. cathayensis andC. japonica, takes an intermediate position between these two species. Analysis of diagnostic bands demonstrate that neitherC. speciosa norC. ×superba has any bands that do not occur in at least one ofC. cathayensis orC. japonica. Moreover,C. speciosa and the partly overlapping taxonC. ×superba are comparatively heterogeneous, which is also in accordance with a hybrid origin. Intraspecific variation was studied mainly inC. japonica; plants obtained from different sources of material formed well separated groups in the cluster analysis.     

Chloroplast DNA diversity in the genusRubus (Rosaceae) revealed by Southern hybridization

The variability in chloroplast DNA type of 20Rubus genotypes was examined by Southern hybridization. DNA extracted from theRubus accessions was digested with two restriction enzymes (EcoRI and EcoRV) and heterologous chloroplast DNA sequences from barley and pea were used as probes to detectRubus chloroplast DNA sequences on Southern blots ofRubus total DNA. Restriction fragment length polymorphism was detected and a total of 92 restriction fragments were generated by the probe/enzyme combinations examined. Cladistic principles based on the parsimony assumption were used to assemble a phylogenetic tree based on chloroplast restriction fragment length data. The phylogenetic tree grouped the taxonomically defined species and is in general agreement with information based on morphological criteria. However, the Japanese red raspberryR. illecebrosus was shown to have diverged considerably in terms of evolutionary time from other species in subg.Idaeobatus. Furthermore, the molecular approach provides a quantitative estimate of the relationship between species that is difficult to obtain from morphological data. In order to complement the chloroplast DNA information a ribosomal DNA probe was also included in the analysis and provided further information on the phylogenetic relationships withinRubus.     

Pollination biology of annual and perennialLeonotis species (Lamiaceae)

The pollination syndromes ofLeonotis (Pers.)R. Br. are discussed. Ornithophily accounts for most of the nutlets set in perennialLeonotis species but in the annual species [L. nepetifolia (L.)R. Br.] autogamy prevails.Leonotis species are predominantly pollinated by a variety of sunbirds, although bees are also involved. Nectar is sucrose-dominant in perennial species but hexose-dominant in the annual.     

Reproductive isolation of two sympatric subspecies ofJuniperus phoenicea (Cupressaceae) in southern Spain

The phenology, reproductive cycle and cone crop of two sympatric subspecies ofJuniperus phoenicea (Cupressaceae) were studied during three consecutive years in southern Spain. The flowering pattern of each subspecies was constant during this period: inJ. phoenicea subsp.turbinata flowering was always in October–November, whileJ. phoenicea subsp.phoenicea flowered in February–March. There was no overlap between the flowering periods of the two taxa. The reproductive cycle of the two subspecies was similar, though there were some important differences because of their flowering times. Male cone development in both subspecies occurred in autumn, but the male cones ofJ. phoenicea subsp.phoenicea did not shed pollen until the end of February. InJ. phoenicea subsp.turbinata, the gap between pollination and fertilisation was seven months while inJ. phoenicea subsp.phoenicea it was only three months, fertilisation taking place at the same time in the two taxa. Post-fertilisation events were similar in the two subspecies, leading to a cycle of two years inJ. phoenicea subsp.turbinata and a shorter one of about 20 months inJ. phoenicea subsp.phoenicea. Alternating good and slight seed cone crops were found in both taxa during the three years studied, the good crops of one subspecies coinciding with the slight crops of the other one. Although the proximity of the two subspecies and method of pollination could make hybridisation between the taxa possible, the different flowering seasons prevent hybridisation isolating them reproductively.