THE EVOLUTION OF INSECT-MEDIATED SELF-POLLINATION FROM AN OUTCROSSING SYSTEM IN CALYPTRIDIUM (PORTULACACEAE)

Calyptridium monospermum (Portulacaceae) comprises two biological races visited by different groups of insects. One race, pollinated by a bumblebee, Bombus vosnesenskii (Apidae), is outcrossing, while the other race is pollinated casually by a variety of other insects whose visits result in insect-mediated self-pollination and geitonogamy within the inflorescence. Insect-mediated selfing is also the mode of pollination in the closely related species, C. umbellatum. While all plants of both species are self-compatible, insect visitation is necessary for good seed set. Selfing populations of C. monospermum exhibit many floral adaptations for insect-mediated self-pollination which parallel those of the selfing C. umbellatum, while retaining vegetative characteristics typical of C. monospermum. These floral traits involve flower color and odor, style and stamen orientation, size of stigmatic surfaces, number of pollen grains produced, density of open flowers on inflorescences, and presence or absence of protogyny. Artifical pollination experiments show that these floral adaptations are effective in increasing the probability of insect-mediated self-pollination. Insect-mediated selfing in C. umbellatum and in some populations of C. monospermum is encouraged and probably made necessary by the inconstant pollinating behavior of the insects which visit these plants, as shown by the large percentage of non-Calyptridium pollen recovered from the bodies of insects captured while visiting these plants.     

Reproductive biology of mixed-species populations of Goodyera (orchidaceae) in northern Michigan

The reproductive biology ofGoodyera oblongifolia, G. repens var.ophioides andG. tesselata is discussed with emphasis on the reproductive isolating mechanisms operating in mixed-species populations. Cytology, phenology and pollination of the above three species were studied. Artificial hybridizations were made of these three species and ofG. pubescens. Results show that within mixed-species populations,G. oblongifolia,G. repens var.ophioides andG. tesselata are not completely isolated reproductively, and hybridization does occur. The deleterious effects of the loss of gametes to interspecific crosses are reduced by seasonal isolation, perennial growth and geitonogamous seed production which is encouraged by self-compatibility and clonal growth. Thus, hybridization in mixed-species populations is apparently kept to levels low enough to allow the species to maintain their identities.     

Dryinid (Hym.: Dryinidae) parasitoids ofDalbulus leafhopper (Hom.: Cicadellidae) in Mexico

Little is known about the natural enemies of the leafhopperDalbulus spp. (Homoptera: Cicadellidae). Searches for its dryinid (wasps) parasitoids were made in Jalisco, Mexico. Jalisco contains the greatest number ofDalbulus species, and is considered to be near to the center of origin of this leafhopper genus and its host plants: maize, teosintes (Zea spp.) and gamagrasses (Tripsacum spp.). The dryinidGonatopus bartletti was found parasitizingD. maidis on maize and on annual teosinteZea mays spp.parviglumis. G. flavipes was found parasitizingD. elimatus on perennial teosinteZ. perennis; and a new speciesG. moyaraygozai andAnteon ciudadi parasitizingD. quinquenotatus onTripsacum pilosum andT. dactyloides. Parasitism by dryinids was found at altitudes of 680–2,000 m.Dalbulus maidis, the leafhopper species which causes the greatest losses in maize in Latin America, was found to be parasitized from 680–1,760 m. TheDalbulus species associated with annual host plants (maize andZ. mays spp.parviglumis) were parasitized by dryinids during the rainy season, while theDalbulus species associated with perennial host plants (Z. perennis andTripsacum) were parasitized by dryinids during both the rainy and dry season. The greatest diversity of dryinid parasitoids ofDalbulus spp. and the highest levels of parasitism were recorded from perennial plants, indicating that such species are reservoirs of natural enemies ofDalbulus spp.     

Agronomic evaluation of prospective new crop species IV.Dimorphotheca andOsteospermum — sources of dimorphecolic acid

Five species ofDimorphotheca, seventeen species ofOsteospermum, and one species each ofCastalis andChrysanthemoides were evaluated at Chico, California for crop potential as a source of dimorphecolic acid. Several species includingD. sinuata were highly susceptible to a number of diseases. Date of planting strongly influenced flowering period ofD. sinuata andD. pluvialis. D. cuneata showed the most promise for crop development. It had limited disease, relatively good seed retention and cold-tolerance, and considerable variability. With improved disease resistance,D. cuneata could be handled as a perennial seed crop. Its lightweight seed, an important disadvantage, is associated with a high proportion of winged to unwinged seeds.Osteospermum caulescens, O. ecklonis, andO. muricatum also have characteristics that favor crop development.O. ecklonis probably could be handled effectively as a winter annual. Seed of these three species had bushel weights of 30 to 41 pounds, compared with four to five pounds forD. cuneata andD. sinuata. Some preliminary germination work showed seed dormancy, which is probably associated with an after-ripening requirement. Overall, the agronomic characteristics that need improvement were disease resistance, seed retention, and seed form. Prospects for agronomic improvement of the most promising species should be good, because variability was evident even in small test populations.     

Three new species of Dasylirion (Nolinaceae) from Mexico and a clarification of the D. longissimum complex

Three new species ofDasylirion and a new variety ofD. longissimum Lem. from the mountains of northern Mexico are described and illustrated. Two of the new species are from northwestern Mexico:D. gentryi, with large, rosecolored fruits and glossy, non-waxy leaves; andD. sereke, characterized by roundish fruits with an unusuall large style.Dasylirion miquihuanense is a new species from northeastern Mexico with narrow, strictly upright leaves and widely separated marginal prickles. TheDasylirion longissimum complex consists of two species,D. quadrangulatum S. Wats andD. longissimum Lem., characterized by narrow, quadrangulate leaves with reduced or absents marginal prickles. Distinguishing features of these two species, which have often been confused, are presented andD. longissimum var.treleasei, characterized by small flowers and fruits, is described.     

Studies in the cyperaceae of Thailand

Ten species ofCarex and one species ofKobresia from Thailand are taxonomically discussed, and some new range extensions into Thailand are noted. Described as new areCarex subinclinata andC. thailandica, both belonging to the sectionIndicae, andC. speciosa ssp.latifolia of the sectionRadicales. Two new combinations proposed areCarex helferi ssp.mapanifolia, andC. speciosa ssp.platyrhina.     

A taxonomic study of the genusCalamagrostis on Mount Yakeishidake

Populations of seven species ofCalamagrostis growing on Mt. Yakeishidake were studied from a viewpoint of taxonomy. Four of them (C. sesquifolia, C. fauriei, C. matsumurae, C. gigas) were composed of tetraploid plants with 2n=28 and high pollen fertility.C. matsumurae andC. gigas had sympatric contacts, but no sign of their hybridization could be detected. The population ofC. sachalinensis on this mountain included hexaploids (2n=42) and octoploids (2n=56), and no obvious morphological or ecological differences could be found between them. The population ofC. sachalinensis was estimated to include various ecological races which may be continuously graded. InC. langsdorffi, only octoploid plants were found. Plants with 2n=56+0?1B were found in the population ofC. hakonensis. The pollen features of the collections ofC. langsdorffii, C. sachalinesis andC. hakonensis showed that apomictic seed formation may be more or less developed in them. Populations of these species on Mt. Yakeishidake were clearly separated morphologically. It was concluded that the populations of the seven species examined each have a unity and that strains ofC. langsdorffii, C. sachalinensis andC. hakonensis found on Mt. Yakeishidake are confined to those of a derived type.     

Notes on calycophyllous Rubiaceae. Part I. Morphological comparisons of the genera Chimarrhis,Bathysa, and Calycophyllum,with new combinations and a new species,Chimarrhis gentryana

A comparison of some genera of the Condaminecae (Rubiaceae) with a few taxa of closely related tribes (Rondeletieae, Calycophylleae, and Cinchoneae) revealed that some species ofChimarrhis (Condamineeae s. 1.),Bathysa (Rondeletieae), andCalycophyllum (Calycophylleae) are often misassigned to genera. The taxonomic significance of calycophylls is discussed; the generic boundaries ofChimarrhis, Bathysa, andCalycophyllum are reevaluated; and their similarities and differences are discussed. As a result, a new calycophyllous species ofChimarrhis from the Amazon,C. gentryana, is described, two of its species are transferred toBathysa (B. Bathysoides, B. perijaënsis), and one species ofBathysa (B. difformis) is reduced to synonymy underChimarrhis (C. turbinata).     

Pollenfertility and seed formation in theOrnithogalum umbellatum/angustifolium complex (Liliaceae/Scilloideae)

The pollen fertility and seed formation of six species of theOrnithogalum umbellatum/angustifolium complex and of seven related species were studied. Four types of pollen grains could be recognized. The pollen fertility varied greatly in this complex and is not related to the ploidy level. The seed formation ofO. umbellatum showed an adaptation to a subcontinental-Mediterranean climate, that ofO. angustifolium to an Atlantic climate. In both cases raindrops seem to be important for pollination, in view of the absence of insect pollinators. After open pollination 113 seedlings were obtained in four species. Their chromosome numbers were determined. Nearly all the cultivated seedlings were aneuploid, which points to a positive selection of euploids in nature, because aneuploid individuals are rare in the wild.Biosystematic Studies on theOrnithogalum umbellatum/angustifolium Complex III.—Previous parts of this series are Part I: Taxonomy. Proceeding Kon. Ned. Acad. Wet. series C,85 (4), 563–574 (1982) andvan Raamsdonk (1984).     

Chromosome numbers and their taxonomic implications for eight Brazilian andropogons (Poaceae: Andropogoneae)

Eleven chromosome counts are reported for Brazilian populations of eight species ofAndropogon. Counts for five of the species are first reports for the species. Four of these species,A. arenarius, A. glaziovii, A. lateralis, andA. lindmanii, are hexaploids (n=30) and belong to a group of about a dozen species informally referred to as theAndropogon lateralis complex. Two other species of this complex,A. bicornis andA. hypogynus, we also found to be hexaploids, in agreement with previous reports. Diploid counts (n=10) forA. macrothrix (a first report) andA. virgatus (the same as two previous reports) support the morphological affinities of these two species to other species complexes withinAndropogon.     

Some biochemical characteristics of fungi isolated from salmonid eggs

Fungal isolates from salmonid eggs displayed apparently unique patterns of biochemical characteristics at both the generic and specific levels. of the five genera examinedAchlya andPythium were able to assimilate 13–16 out of 19 carbohydrates.Aphanomyces was able to assimilate only glucose and starch, which was assimilated by all isolates. Members ofSaprolegnia displayed identical patterns of carbohydrate assimilation, except forS. hypogyna, which was also able to assimilate melibiose, in common withAchlya, Pythium, andLeptolegnia. Pythium was the only genus capable of assimilating salicin. OnlyAchlya andP. monospermum were able to assimilate rhamnose. In terms of amino acid assimilation isolates ofSaprolegnia ferax andS. diclina displayed an identical patterns, as did isolates ofS. parasitica andS. hypogyna. OnlyAphanomyces frigidophilus isolate was capable of assimilating cysteine. All genera exceptPythium assimilated glutamine, a fundamental amino acid. All isolates exhibited lipase and fatty acid esterase activities but no cellulase acitivity. The biochemical characteristics discovered in this study offer possibilities for identification and classification of these fungi, which are discussed herein.     

New species of Cuphea section Melvilla (Lythraceae) and an annotated key to the section

Three novelties inCuphea sectionMelvilla subsect.Pachycalyx are described from Brazil;C. andersonii andC. cylindracea from Pará, andC. sabulosa from Amazonas. An annotated key to the 47 species ofCuphea sectionMelvilla is provided, the first since the 1903 monograph of the family, which then included 27 species in the section. The key identifies those species ofCuphea with thick, dorsally convex, red- or yellow-tubed flowers distributed from Mexico to Argentina.     

Biosystematic studies on the umbellatum-angustifolium complex of the genus Ornithogalum. (Liliaceae). II. Genome characterization and evolution

Chromosome banding techniques (Giemsa and fluorochrome staining) were used to investigate Ornithogalum umbellatum L., O. angustifolium Bor. and 11 related taxa. Nine different basic Q-banding patterns, referred to as genomes, could be recognised. These patterns are indicated by capitals (A–E, P–S). Six of the nine basic genome types can be subdivided into different subtypes. The B genome was found in the two bulbilliferous species, i.e. O. umbellatum and O. angustifolium. It occurs in a number of combinations together with the A, C, D and E genomes. Genome combinations of these five basic types were found in seven species. Six of them share morphological characteristics. These species are: O. monticolum Jord. & Fourr., O. baeticum Boiss., O. angustifolium, O. refractum, Kit., O. umbellatum and O. algeriense Jord. & Fourr. A seventh species, O. platyphyllum Boiss., in which the E genome occurs, can be regarded as an intermediate between this complex and the O. montanum group. Each species is treated extensively; its morphology, geographical distribution, chromosome number and banding patterns are discussed separately. A model of the probable course of the evolution in this complex during the last two glaciation periods is described. In this model attention is paid to ecological differentiation, migration leading to the present distribution patterns, hybridization followed by polyploidization and to fixation, which may be the result of chromosomal rearrangements that prevent regular meiosis. Some cytotypes, formerly regarded as O. umbellatum, are now classified in other species. A second polyploid complex in which these species occur, is probably more widely distributed in south-eastern Europe than is generally thought at present. The species O. exscapum Ten., O. nivale Boiss., O. comosum L., O. collinum Guss. and O. gussonei Ten. p.p. are components of this complex. The delimitation of this complex as a whole and the relationship between its diploid and polyploid components have still to be clarified.     

Genetics of food preference inDrosophila sechellia

To reveal the genetic mechanism of host selection in a monophagous fruit flyDrosophila sechellia, olfactory responses and oviposition preferences of this species were compared with those of closely related polyphagous species,D. simulans andD. melanogaster. Adult flies ofD. sechellia were strongly attracted to the ripe fruit ofMorinda citrifolia which is known to be the sole breeding site of this species. They were also attracted to the odor ofn-caproic acid which is contained in the ripe fruit ofM. citrifolia and is presumably responsible for the characteristic odor of the fruit. In contrast,D. simulans andD. melanogaster showed a strong repulsion ton-caproic acid. In parallel with the olfactory responses,D. sechellia females laid eggs preferentially on a medium containingn-caproic acid, to which the other two species showed an aversion. Genetic analyses using the hybrid progeny betweenD. sechellia andD. simulans suggested that the species differences in these behaviors are controlled by gene(s) located on the second chromosome.     

Contribution to the biology of germination of four species ofChenopodium album agg. under different condition

The study investigated various factors stimulating germination of seeds of four species ofChenopodium album agg.—C. album L. s. str.,C. ficifolium Sm.,C. strictum Roth,C. suecicum J. Murr. These factors were: storage in wet and cold, alternating temperature, nitrates mainly in combination with light and, to a lesser degree, the duration of chilling. Germination was inhibited by darkness, which was most marked with seeds ofC. strictum. The effect of alternating temperature was better on the germination ofC. ficifolium andC. suecicum than on that ofC. album andC. strictum. We also discussed several differences in specific reactions of the individual species to the factors under consideration.     

Host specificity ofPareuchaetes insulata (Lep.: Arctiidae), a biological control agent forChromolaena odorata (Compositae)

Larvae of the arctiid moth,Pareuchaetes insulata, from Florida fed on the leaves ofChromolaena odorata, a serious composite, alien weed in Natal, South Africa. In starvation test trials using 48 plant species,P. insulata completed its development onC. odorata andAgeratum houstonianum. Subsequent attempts to cultureP. insulata on these two plants was only successful onC. odorata. The biology ofP. insulata is similar to that of two other well studiedPareuchaetes species namelyP. pseudoinsulata andP. aurata aurata. Repeated defoliation ofC. odorata byP. insulata could contribute to its control as has been found withP. pseudoinsulata in Guam.Pareuchaetes insulata has been approved for release as a biological control agent ofC. odorata in South Africa.     

Cannibalism and interspecific predation in two predatory ladybirds in relation to prey abundance in the field

Life tables for two predatory ladybirds,Coccinella septempunctata andHarmonia axyridis, were constructed in two years in which prey abundance differed. The prey aphid,Aphis gossypii, was abundant on its primary host from late May to late June. Females ofH. axyridis andC. septempumctata laid their eggs during the increase and peak in aphid abundance. The oviposition period ofC. septempunctata started before and was shorter than that ofH. axyridis. In both species, intraguild predation and/or cannibalism of the egg and fourth instar stages, but rarely of other developmental stages, were observed. Fourth instar larvae ofH. axyridis had to complete their development when aphids were scarce more frequently than those ofC. septempunctata. The highest frequency of intra- and interspecific predation was of fourth instarH. axyridis larvae. In terms of intraguild predation, the larvae ofH. axyridis preyed on larvae ofC. septempunctata, but the reverse was not observed. Percentage survival from egg to adult inH. axyridis was higher than inC. septempunctata in both years, and least in both species in the year of low aphid abundance. These results suggest that prey abundance influenced the frequency of cannibalism and intraguild predation, which were important in structuring this guild of ladybirds.     

Castilleja (Scrophulariaceae) of Costa Rica and Panama

The mountains of Costa Rica and western Panama constitute a natural floristic region that is inhabited by six species ofCastilleja.Castilleja talamancensis, C. lentii andC. tayloriorum are described as new. The remaining three areC. arvensis,C. irasuensis andC. quirosii. All butC. arvensis are endemic to the area. The six species are keyed, described, illustrated, mapped and documented with literature and specimen citations.