Chromosome numbers in AustralianEuphrasia (Scrophulariaceae)

Chromosome numbers for six Australian taxa ofEuphrasia have been determined. Improved staining techniques have shown that numbers for four of the taxa published previously by the first author were incorrect. The investigated taxa show high ploidy levels with an apparent base number of x = 11, the same as for the genus outside Australia.Dedicated to Prof. DrElisabeth Tschermak-Woess on the occasion of her 70th birthday.     

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.     

Host influence on floral variability inOrthocarpus densiflorus (Scrophulariaceae)

This study investigates the influence of host plants on the expression of floral variability in the hemiparasiteOrthocarpus densiflorus (Scrophulariaceae), to determine if interaction with host plants can facilitate the expression of normally hidden genes. Style extension inO. densiflorus is highly uniform in natural populations, with less than 1% of the individuals exhibiting an aberrant extended-style condition. Both seed treatment with giberellic acid and parasitic development with host plants significantly facilitates the expression of extended-style in progenies that show only minimal expression when grown autotrophically. Artificial selection experiments demonstrate the range of potential phenotypic variation to be under genetic control, and differentially influenced by the host environment. Although the biochemical basis of the host influence is unknown, some host plants produce stimuli that apparently disrupt buffering inO. densiflorus and expose normally unexpressed genetic variability to selection. If variation in other traits is similarly affected, the influence of host chemistry may provide parasitic plants with a greater than normal opportunity for rapid selectional change.     

Morphometric variation in theAlonsoa meridionalis complex (Scrophulariaceae)

Morphological field studies of 27 populations of theA. meridionalis complex were conducted in Ecuador. It is possible to distinguish four different form series by the position of the stamens in relation to the style. This trait was congruent with the overall morphometric variation, shown by the results of a canonical discriminant analysis (CDA). The taxonomy of the species complex is discussed based upon the results of the CDA. The degree of outcrossing varied in different form series, from a comparatively high degree of selfing to predominantly outcrossing, as indicated by the variation within relative to among populations. This is probably due to the varying potentials for self-deposition owing to differences in the degree of herkogamy.     

Pollination of four sympatric species ofAngelonia (Scrophulariaceae) by oil-collecting bees in NE. Brazil

The manner whereby the oil-producing bisaccate flowers ofAngelonia (Scrophulariaceae) are pollinated by female oil-collecting bees is reported for the first time. Observations were made in the Caatinga formation of Pernambuco, NE. Brazil, on four synchronopatric species. These differ in sizes and structural details of the corolla, level of flower exposition, and habitat preferences. All legitimate visitors wereCentris spp. (Anthophoridae):Angelonia hirta was mainly pollinated byC. fuscata andA. pubescens byC. hyptidis; A. bisaccata andA. hookeriana shared an unidentified species. Several exomalopsine, tetrapediine and meliponid bees exploit the flowers less descriminately for oil or pollen, respectively, without regularly contacting anthers and stigma. The flowers are protandrous, and are self-incompatible except those of the annualA. pubescens. After alighting, theCentris bees introduce their front legs simultaneously into each of the pouches and start alternate collecting movements to gather the oil from the trichome elaiophores. While doing so, they are forced by projections of the corolla floor to press their head under the anthers and stigma, whereby pollen is transferred with their frons or clypeus. On account of their collector type and behaviour,C. fuscata andC. spec. are not specialized toAngelonia but may equally exploit other nonrelated taxa for oil, whereasC. hyptidis exhibits oligolecty onA. pubescens. It possesses relatively elongate forelegs with padlike collectors suitable for sweeping the lipids from the scattered glandular hairs inside the divergent spurs of its host. It is the only species that also collects pollen (by buzzing) from the oil host.A. hirta and relatives, provided with dense elaiophore carpets, are, for their part, adapted to scrapingCentris species with typical oil collectors. Flower and bee phenologies, although largely dependent on the irregular rainfalls, are not always coincident.     

Two newVeronica species (Scrophulariaceae) of Turkey and Iraq

Veronica davisii M. A.Fischer, sp. n., limited to the mountains of Kurdistan (S. E. Turkey and N. Iraq), is related to the Turkish-CaucasianV. gentianoidesVahl.—V. montbretii M. A.Fischer, sp. n., a local endemic of Erzincan prov. (E. Anatolia), shows affinities to the CaucasianV. liwanensisC. Koch and to the Turkish endemicV. oltensisWoron. & Schelk. from Erzurum province.     

Gametogenesis,endosperm development,and embryogeny inMicrocarpaea muscosa (Scrophulariaceae,Gratioleae)

InMicrocarpaea muscosa gametogenesis, embryo sac development (Polygonum type), endosperm development (cellular), embryogeny (Onagrad type), and seed structure are described. The different modes of endosperm development withinGratioleae are compared.     

SEM observations on seeds ofStriga spp. andBuchnera americana (Scrophulariaceae)

Seeds of the root parasitesStriga (several spp.) andBuchnera americana were examined by means of SEM. The surface patterns of the seeds in both genera resemble each other closely, especially those ofS. angustifolia andB. americana. SomeStriga spp. can be clearly distinguished by their surface characteristics, while this is quite difficult in others. The taxonomic value of the seed surface features ofStriga andBuchnera is discussed.     

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.     

The consequences of specialization for pollination in a rare South African shrub,Ixianthes retzioides (Scrophulariaceae)

Ixianthes retzioides is a rare South African shrub with large yellow oil-secreting flowers. Populations studied previously revealed low levels of reproductive success and the absence of a specialized oil-collecting pollinator. We report the discovery of a population in which the predicted specialist pollinator,Rediviva gigas, is present. The presence of this oil-collecting bee resulted in a mean fruit set per plant of 97.2 ± 8.3% (N = 9) and a mean seed set of 331.6 ± 162.6 (N = 52). This represents a 7.4-fold increase in fruit set and a 7.8-fold increase in seed set over a previously studied population lacking the specialist pollinator. The contrast between populations with and without the specialist pollinator dramatically illustrates the potential benefits and costs of specialization for pollination, respectively.     

Life history variation and infraspecific heterochrony inRhinanthus glacialis (Scrophulariaceae)

Comparative cultivation experiments were made with 14 populations of the annual, hemiparasitic speciesRhinanthus glacialis from seven different habitat types. Phenological data were recorded and plants from field samples and from corresponding experimental samples were morphologically analysed.There are up to ten weeks difference in the start of flowering between means of the extreme experimental populations. Flowering time variation correlates with the number of internodes and also with most of the other morphological characters. Flowering time also shows close relationships to different grassland types and the examined populations appear to be well-adapted to the environmental conditions in natural or man-influenced grassland types as far as flowering time is concerned. The number of internodes is mostly insensitive to the applied experimental influences. The rate of internode production is constant. Trade-offs are suggested for some morphological traits (i.e., few internodes with few branches and thus few flowers as trade-off for early flowering). — Previous studies of life history variation based on population data have not been incorporated into the theory of heterochrony. The pattern of life history variation of populations ofR. glacialis together with information about morphology, ecology, and phylogeny suggests that some variants have evolved from ancestors via heterochronic processes. Earlier flowering populations from montane hay meadows, litter meadows, and dry meadows belong to paedomorphic variants. These have fewer internodes and branches as well as reduced height in comparison with the suggested ancestor. Later flowering populations from subalpine limestone grassland belong to a peramorphic variant with more internodes, more branches, and taller stems in comparison with the suggested ancestor.     

Comparative studies on the reproductive systems ofMazus japonicus andM. miquelii (Scrophulariaceae)

Mazus japonicus is predominantly self-pollinated,M. miquelii mostly cross-pollinated, with a low degree of self-incompatibility. Correlated differences effect structure, development and seismonasty of the stigma, spatial relationships of stigma and anthers, and pollinator visits.M. japonicus produces numerous and light,M. miquelii fewer and heavier seeds. Growth experiments under different temperature regimes demonstrate thatM. japonicus dies after flowering and fruiting, and behaves as an annual, whileM. miquelii has additional asexual propagation and is clearly perennial.M. japonicus grows in somewhat drier and more disturbed habitats thanM. miquelii.     

Local evolution of obligate autogamy inEpipactis helleborine subsp.neerlandica (Orchidaceae)

Isozyme analysis was used to assess the origin of the DanishEpipactis renzii, a local endemic of open coastal dunes. It seems to have evolved recently in several local populations of the more or less allogamousE. helleborine subsp.neerlandica. The obligately autogamousE. renzii is restricted to the easternmost part of the Danish range ofE. helleborine subsp.neerlandica, indicating that transition to obligate autogamy has been a selective advantage in that area. This may be explained by water stress, caused by a higher evapotranspiration (cf. the mean temperature of July which increases towards the east) — obligate autogamy shortens the time span from anthesis to fruit set due to a rapid pollination process. We propose thatE. renzii should only be recognized as a variety ofE. helleborine subsp.neerlandica.     

Host plants of someRhinanthoideae (Scrophulariaceae) of eastern North America

Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.     

The pollen morphology ofOdontites (Scrophulariaceae) and its taxonomic significance

The pollen morphology of 29 species ofOdontites and related genera was examined by light and scanning electron microscopy. Three major pollen types differing fundamentally in exine sculpturing were found. In the parasitic tribePedicularieae retipilate sculpturing is the most widespread type representing a plesiomorphic character state from which the two other types are derived. Of these, reticulate sculpturing is confined toOdontites, whereas a complex retirugulate pattern was found only in the monotypic Near East genusBornmuellerantha. Within the retipilate and the reticulate major types eight minor types were distinguished based on the differential correlation of exine surface morphology, size, shape and amb form. The pollen data are generally well correlated with macromorphological features and furnish important taxonomic characters at the genus—as well as at the specieslevel.     

Zwei neue Hybriden in der GattungEuphrasia (Scrophulariaceae)

The following new hybrids are described:Euphrasia ×dilata = E. hirtella Jordan exReuter ×alpina Lam.;Euphrasia ×trikoviana = E. tricuspidata L. ×rostkoviana Hayne. The chromosome number ofEuphrasia tricuspidata L. has been established for the first time: 2n = 22.

     

Development of endosperm inScrophularia himalensis with a discussion on the variation in the endosperm of the tribeScrophularieae (Scrophulariaceae)

Scrophularia himalensis has anab initio cellular endosperm. A transverse division separates a micropylar chamber from a chalazal chamber. The second division is vertical in both, the third is also vertical but at right angles to the second and restricted to the micropylar chamber just as the fourth transverse division. The four-celled micropylar haustorium is branched, highly aggressive, and persists for a long time during seed development. The bicelled chalazal haustorium is non-aggressive and is relatively short-lived. The endosperm proper is ruminate. Variation in the early ontogeny of the endosperm and the structure of endosperm haustoria in the tribeScrophularieae are evaluated.     

Paulownia taiwaniana,a hybrid betweenP. fortunei andP. kawakamii (Scrophulariaceae)

Paulownia taiwaniana, the widely cultivated, commercially important tree, has been suspected of being of hybrid origin at least since its original publication in 1975. Evidence in support of this thesis, derived from a number of different investigations, is presented in this paper.—Strong evidence comes from a controlled pollination study of the two supposed parental species,P. kawakamii andP. fortunei. F₁ seedlings, derived from reciprocal crosses between the suspected parents, exhibited identical banding patterns for a number of enzymes (such as SKDH, GOT, and IDH) withP. taiwaniana, when separated by electrophoresis. Furthermore, comparative morphological studies of trichomes and wood parenchyma patterns between the purported parents andP. taiwaniana reveal that this latter qualitatively exhibits characteristics that combine features of both of the suspected parental types. Biochemically, eight enzyme systems were compared in the three species here under discussion, and, without exception, the electrophoretic banding patterns exhibited byP. taiwaniana represented a combination of the alleles of the other two species. Perhaps the most convincing evidence comes from a genetic analysis of the progeny obtained by selfingP. taiwaniana. Genotypic segregation of the offspring based on a single locus each of SKDH and PGI fit the 1:2:1 hypothesis. Genotypic segregation of the offspring based on two loci each of SP and GOT fit the ratio of 3:6:3:1:2:1. This, taken in conjunction with the other data presented, clearly suggests thatP. taiwaniana is a hybrid involvingP. kawakamii andP. fortunei.     

Phylogeny of the tribe Antirrhineae (Scrophulariaceae) based on morphological andndhF sequence data

Phylogenetic relationships within the tribe Antirrhineae (Scrophulariaceae) are analysed and discussed on the basis of parsimony analyses of morphological andndhF gene sequence data. The results indicate that the tribe Antirrhineae consists of four major groups of genera, theAnarrhinum clade, theGambelia clade, theMaurandya clade, and theAntirrhinum clade. TheAnarrhinum clade, consisting of the Old World bee-pollinated generaAnarrhinum andKickxia, is sister to the rest of the tribe. TheGambelia clade consists of the New World generaGambelia andGalvezia, which are very closely related and pollinated by hummingbirds. TheMaurandya clade consists of one subclade includingMaurandya and a number of related bee- or hummingbird-pollinated New World genera and another subclade with the Old World bee-pollinated generaAsarina andCymbalaria. TheAntirrhinum clade consists mainly of bee-pollinated Old World genera, such asAntirrhinum, Linaria, Chaenorhinum, and their segregates, but also includes the New World generaMohavea andHowelliella, of which the latter is known to be partly pollinated by hummingbirds. It is concluded that hummingbirdpollination has evolved independently within Antirrhineae at least three times from bee-pollinated ancestors.