Resource depression in Daphnia galeata, Daphnia cucullata and their interspecific hybrid: life history consequences

In this study, the effect of the food concentration on severallife history parameters of Daphnia galeata, Daphnia cucullataand the hybrid between these two species was examined. The foodconcentration had a significant effect on both growth and reproductionof all three taxa. Mortality was highly species specific, andto a lesser extent dependent on the food concentration. Changesin life history parameters resulted in changes in the intrinsicrate of population increase (r). The food dependence of thedifferent species was found to be different. Daphnia cucullatahad a relatively constant and low r. The r values for the hybridvaried most, with low values compared with the parental specieswhen grown at low food levels and relatively high values athigher food concentrations. Our results suggest that when foodconcentrations are high the hybrid will have a selective advantageover both parental species, but that at lower food levels D.galeatawill have an advantage over both D.cucullata and the hybrid.     

Spatial and temporal patterns of sexual reproduction in a hybrid Daphnia species complex

Evidence for extensive interspecific hybridization among speciesof the genus Daphnia has been accumulating on a global scale.Although there is evidence for limited gene flow between taxavia hybridization, many species still maintain discrete morphologicaland molecular characteristics. We studied temporal and spatialpatterns of sexual reproduction within the Daphnia galeata–hyalina–cucullatahybrid species complex in a lake (Plußsee), located innorthern Germany. Allozyme electrophoresis allowed us to trackseasonal changes in taxon composition as well as the quantificationof back-crosses. Sexually-reproducing animals (ephippial femalesand males) were mainly found in autumn. The simultaneous presenceof sexual morphs of D. galeata and D. galeata x hyalina withthe dominant D. hyalina taxa makes recent hybridization, aswell as back-crossing, plausible. Males and ephippial femalesof D. hyalina were not back-crossed as were the parthenogeneticfemales. The low number of sexual clones of the hybrid D. galeatax hyalina might reflect its reduced fertility, although thesefew clones were detected in high densities. Only hybrid-clonesthat had a back-cross genotype (towards D. hyalina) exhibitedephippial females and males. This indicates that male and ephippialfemale production within the Daphnia taxa is not random, whichmight increase the chance for the parental Daphnia species toremain distinct.     

Diet selection by copepods in the presence of cyanobacteria

Boeckella, the dominant calanoid in many Southern Hemispherelakes, can survive, grow and reproduce to varying extents onmonocultures of cyanobacteria. In this study, we determinedthe effects of algal and cyanobacterial foods of different nutritionalvalue and concentration on food preferences of adult femaleBoeckella trianiculata and Boeckella hamata. Four species ofcyanobacteria (Anabaena flos-aquae, Nostoc sp. 2, OscillatoriatenuisandMicrocystis aeruginosa) were offered alone and mixedwith equal biomasses of Cryptomonas sp., Choricystis or a cyanobacterium.Food preferences were calculated as ratios of the rates at whichthe copepods removed each food at high and low food concentrations.In high-concentration mixtures with cyanobacteria, Cryptomonaswas consistently preferred by both Boeckella spp. In low-concentrationmixtures, both Boeckella spp. preferred Anabaena and Nostoc,which they removed at high rates(81–142 ml mg^–1h^–1), although Cryptomonas was selected in preferenceto Oscillatoria and Microcystis. When fed mixtures of filamentouscyanobacteria, both species of Boeckella showed invariant discriminationagainst Nostoc, andshifts in preference between Anabaena andOscillatoria that were related to food concentration. Microcystis,the least favouredfood, appeared to have a toxic effect on B.triarticulata. ¹Present address: Nursing and Midwifery Department, Otago Polytechnic,Forth Street, Dunedin, New Zealand     

Isozyme Evidence for Natural Hybridization in Phlomis (Lamiaceae): Hybrid Origin of the RareP.xmargaritae

Phlomisxmargaritae is a rare and sterile hybrid taxon foundin a single endangered population in southern Spain. It waspreviously described as a morphologically intermediate hybrid,putatively between Phlomis purpurea and P. composita. The presentstudy used allozymes as molecular markers to assess the hybrididentity ofP.xmargaritae . Ten putative loci from seven enzymesystems were resolved: five were monomorphic and fixed acrossall taxa studied and the rest (Aat-1, Aat-2, 6-Pgdh-2, Pgi andPgm) were polymorphic in at least one taxon. The two parentaltaxa are fixed for different alleles at 6-Pgdh-2 and show distinctallelic frequency differences for four other loci. Phlomisxmargaritaedisplays fixed heterozygous phenotypes for four of the fivepolymorphic loci, these being composed of combinations of thealleles found in the parental taxa. No unique alleles were detectedin P.xmargaritae. We conclude that this taxon is of hybrid originand confirm the identity of the parental taxa involved. It isfurther suggested that this population is composed of individualsthat are recent F₁hybrids that have not undergone backcrossingor introgression. Global conservation measures are necessaryfor the whole hybrid system in this location since further continuousassessment could reveal the evolutionary input of hybridizationin Phlomis.Copyright 2000 Annals of Botany Company Endangered species, genetic diversity, isozyme variation, hybrid species, Phlomisxmargaritae, plant conservation, population genetics, Lamiaceae, Spain.     

Life history responses of Daphnia clones to toxic Microcystis at different food levels

We examined how the amount of food of good quality, Scenedrsmusobtusiusculus, influenced the toxic effects of the cyanobacteriumMicrocystu aeruginosa on Daphnia pulex in a 21 day life tableexperiment. Our results show that all life history traits studied,i.e. longevity, growth and reproduction, of D.pulex were negativelyaffected by toxic Microcystis. The detrimental effects on theselife history traits were less pronounced at increasing foodlevels. In addition, D.pule.x clones differed in their lifehistory responses to toxic Microcystis, suggesting that thepresence of toxic cyanobacteria may modify the outcome amongD.pulex clones.     

Interspecific Hybridization in the Genus Dioscorea

Interspecific hybridization between Dioscorea alata (2n = 60).D. deltoidea (2n = 20), D. floribunda (2n = 36), D. composita(2n = 36), and D. friedrichsthallii (2n = 36) has revealed levelsof crossability consisting of successful crossing and normalgermination of hybrid seeds, successful crossing but poor germinationof hybrid seeds, crosses not successful due to a pre-fertilizationovular breakdown, and crosses not successful due to post-fertilizationovular breakdown. In general the three Central American species with basic chromosomenumber as 9, namely D. floribunda, D. composita, and D. friedrichsthalliiare cross compatible. In crosses involving D. floribunda withD. composita and D. floribunda with D. friedrichsthallii viablehybrids were obtained. The cross between D. friedrichsthalliiand D. composita is also successful but germination of the hybridseeds is greatly reduced. The cross of D. composita female withthe male D. friedrichsthallii was an exception to the generalcompatibility between these three species. In this cross thefertilized embryo aborted after attaining four-celled stage. The crosses between the two Old World species with basic chromosomenumber as 10, namely D. alata and D. deltoidea with each otherand with the above named three Central American species werenot successful. D. alata had pollen grains which rarely germinated.When D. alata was used as the female parent, the pollen tubesof other species grew down the style but no fertilization tookplace. The reciprocal crosses of D. deltoidea with the CentralAmerican species gave differential results. When D. deltoideawas used as the female parent no fertilization took place. However,when D. deltoidea was used as the male parent the fertilizedembryo aborted after attaining globular stage.     

Studies on Plankton Parasites: III. Examples of the Interaction between Parasitism and other Factors determining the Growth of Diatoms

This paper deals with the interrelations of populations of planktonorganisms and their parasites in two English lakes. The organismsconsidered are diatoms, mainly Asterionella farmosa but alsoTabellaria fenestrata var. asterionelloides, Fragilaria crotonensis,and Melosira italica, with a blue-green Oscillatoria agardhiivar. isothrix. The parasites are the Chytrids Rhizophidium planktonicumon diatoms and R. megarrhizum on Oscillatoria. The parasites may delay the time of maximum algal number ormay decrease the size of the maximum. Generally parasitism ofone alga favoura the development of others. Various other complexitiesarise from the interaction of these factors with nutritionalconditions.     

Shifting Regimes and Changing Interactions in the Lake Washington,U.S.A., Plankton Community from 1962–1994

Understanding how changing climate, nutrient regimes, and invasive species shift food web structure is critically important in ecology. Most analytical approaches, however, assume static species interactions and environmental effects across time. Therefore, we applied multivariate autoregressive (MAR) models in a moving window context to test for shifting plankton community interactions and effects of environmental variables on plankton abundance in Lake Washington, U.S.A. from 1962–1994, following reduced nutrient loading in the 1960s and the rise of Daphnia in the 1970s. The moving-window MAR (mwMAR) approach showed shifts in the strengths of interactions between Daphnia, a dominant grazer, and other plankton taxa between a high nutrient, Oscillatoria-dominated regime and a low nutrient, Daphnia-dominated regime. The approach also highlighted the inhibiting influence of the cyanobacterium Oscillatoria on other plankton taxa in the community. Overall community stability was lowest during the period of elevated nutrient loading and Oscillatoria dominance. Despite recent warming of the lake, we found no evidence that anomalous temperatures impacted plankton abundance. Our results suggest mwMAR modeling is a useful approach that can be applied across diverse ecosystems, when questions involve shifting relationships within food webs, and among species and abiotic drivers.     

The IJsselmeer and its phytoplankton--with special attention to the suitability of the lake as a habitat for Oscillatoria agardhii Gom

The IJsselmeer (surface area 1200 km², mean depth 4.5 m, residencetime 0.4 year, phosphorus load 7 g m^–2 year^–1) isa very important conservation area. Regular summer bloomingof Oscillatoria spp. can depreciate this value, so the boundsof possibility of this kind of blooming have been investigated.Therefore samples were taken along the shore and in the openwater from 1974 to 1982, continuous temperature profile measurementswere made in the same period in the middle of the lake and insitu primary production was measured in 1976 and 1977. The phytoplanktonconsists of green algae throughout the year, diatoms in spring,and blooms of Microcystis aeruginosa in summer. Blooming ofOscillatoria agardhii Gom occurs regularly in summer along theFrisian shore. In 1976, however, a heavy bloom of this algaoccurred in the whole lake. Comparing the IJsselmeer with shallowerOscillatoria-lakes in the Netherlands distinct differences arepresent concerning biomass, chlorophyll a content, relativevolume of the euphotic zone and light-dark cycle. Not only thelarger depth and extensiveness of the IJsselmeer are unfavourablefactors for Oscillatoria, but also the separation by land reclamationof many of the shallow littoral regions from the main body ofthe lake. High temperature and microstratification are neededto develop a bloom in the whole lake.     

Genetic diversity and polyploidy in the cosmopolitan asexual ostracod Cypris pubera

Freshwater ostracods show extensive breeding system variation,but both the cause of breeding system transitions, and the originsof genotypic diversity in asexuals, have yet to be convincinglyexplained. The study reports on the genotypic (based on allozymeelectrophoresis) characteristics of Northern European populationsof the globally distributed ostracod Cypris pubera. No malehas ever been described for C. pubera, and none were found inthis study. Genotypic profiles indicated deviations from Hardy–Weinberg(HW) equilibrium, confirming that C. pubera reproduces throughameiotic parthenogenesis, that is, the production of femaleoffspring where the formation of ova is through a mitotic process.Cypris pubera seems to be comprised of diploid clones that arebrown in colour and a series of polyploid clones that are green.The two morphs often occurred in sympatry, but the green morphwas considerably more diverse than the brown. The factors whichcontribute to asexual diversity or elevated ploidy levels inother taxa, such as hybridization, do not appear to be importantfor C. pubera. Thus, this study has established a link betweenpolyploidy and genetic diversity in C. pubera, but the originsof both asexuality and polyploidy remain unclear for this ecologicallysuccessful ostracod.     

Toxic and inhibitory effects of the blue-green alga Microcystis aeruginosa on herbivorous zooplankton

Blooms of blue-green algae are often associated with declinesin populations of large-bodied cladocerans and increased importanceof small cladocerans, copepods, and rotifers. We conducted toxicityand herbivory experiments, using a wide range of herbivore taxa,to test the hypothesis that the blue-green alga Microcystisaeruginosa most strongly inhibits large cladocerans. For a varietyof herbivore taxa, M. aeruginosa was toxic or non-nutritious,and inhibited feeding on co-occurring nutritious food. The rotiferBrachionus calyciflorus was unique in several respects: it wasunaffected by M. aeruginosa toxins, it showed some ability togrow and reproduce on a diet of M. aeruginosa, and it maintainedhigh feeding rates on co-occurring nutritious food in the presenceof bloom densities of M. aeruginosa. There was a strong relationbetween the toxicity of M. aeruginosa and its inhibitory effecton herbivore feeding rates. Copepods strongly avoided consumingM. aeruginosa, but all cladocerans and rotifers tested filteredunicellular M. aeruginosa at rates similar to or higher thannutritious Chlamydomonas reinhardi. Our results indicate thatthere are a variety of mechanisms whereby herbivorous zooplanktoncan coexist with blooms of M. aeruginosa, including resistanceto toxic chemicals (B. calyciflorus), and avoidance of consumptionof M. aeruginosa by chemosensory means (copepods), or by theinability to consume large colonies (some small cladocerans). ¹Present Address: Department of Biology, George Mason University,4400 University Drive, Fairfax, VA 22030, USA     

Morphological adaptations in filtering screens of Daphnia galeata to food quantity and food quality

We reared clones of the waterflea Daphnia galeata, a common grazer in many types of lakes, under several food regimes to study adaptations to feeding conditions in filter screen morphology and life history. As food regimes, we used low and high concentrations of the green alga Scenedesmus, a high concentration of the filamentous cyanobacterium Oscillatoria, and a mixture of Scenedesmus and clay. Natural seston from Lake IJsselmeer was also tested. Clones from two contrasting habitats (mesotrophic versus hypertrophic lake) did not differ in either population growth rate, r, or filtering structures. However, all the clones exhibited phenotypic plasticity when reared under low and high food concentrations. In relation to their body length, daphnids grew larger filter screens with longer setae in response to low food concentrations, thus enhancing filtering efficiency. Supplementing the low food concentration with inert clay particles had no effect on either the growth performance or filter screen morphology. In both cases, the growth and reproduction were low and filtering areas large. Filter screens were of intermediate size when daphnids were supplied with food supporting intermediate growth and reproduction. From these laboratory results, we concluded that the nutritional status of Daphnia is a more important cue for the phenotypic response of the filter screen morphology than particle concentration.      

Dynamics of phytoplankton in the Great Barrier Reef Lagoon

The characteristics of the phytoplankton crop in the centralregion of the Great Barrier Reef were analyzed through two annualcycles together with basic oceanographic parameters. Chlorophylla standing crop and primary production were size fractionatedinto nanoplankton and microplankton components. Community compositionwas determined using the Utermöhl settling technique andcommunity diversities estimated by the Shannon-Weaver equation.The data and analysis are the most comprehensive in existencefor the region, and the first detailed study since the 1928–29Great Barrier Reef expedition. A marked seasonal cycle was identified,contrary to most assumptions, closely associated with precipitationpatterns and nutrients introduced by land drainage. The regionwould rank as mesotrophic with some eutrophic areas in the innerreaches of the Lagoon. Oscillatoria spp. accounted for a largefraction of the majority of phytoplankton maxima and were inverselyrelated to diatom crop densities even under conditions favoringdiatom growth. Microplankton crop species diversities usuallydecreased during extended Oscillatoria blooms. The reduced diversitypersisted after the bloom suggesting that Oscillatoria spp.were the source of extracellular metabolites and/or decompositionproducts adversely influencing diatom microplankton.     

Some Observations on the Diversity of Stomata and Trichomes in Six Species of Dioscorea

Stomata and trichomes are described on the leaves of six speciesof Dioscorea. As many as six types were found in D. bulbiferaand D. oppositifolia, four types in D.hispida and D. wallichii,three types in D. belophylla, but only two types in D. alata.Although there is a diversity of stomata even on the same surface,the predominant type is anomocytic in all the species exceptD. bulbifera in which it is tricytic. Rarely a stoma is alsocyclocytic in D. bulbifera. An increase in the number of subsidiarycells in paracytic, tricytic, or diacytic stomata takes placeby the wall formation in them. Similarly a reduction in thenumber of subsidiary cells of a tetracytic stoma is the resultof lateral subsidiary cells assuming the form of epidermal cells.Abnormalities such as a stoma with one guard cell, degenerationof guard cells, and contiguous stomata are also met with. Theorganization of different types of stomata is studied in D.bulbifera and D. wallichii and shown to be perigenous. Capitateglandular hairs were seen on the leaves of D. belophylla, D.bulbifera, D. hispida, and D. wallichii but non-glandular, uniseriate,3-celled trichomes were observed only in D. hispida.     

Variation in Two Sorbus Species Endemic to the Isle of Arran, Scotland

A study of the morphology of plants from four species of Sorbus,S. arraensis, S. pseudofennica, S. aucuparia and S. rupicola,two of them endemic to North Arran, suggested that the originof the two endemic groups could have been by hybridization. Variation between individuals within the hybrid groups indicatesthat the two groups, probably of hybrid origin (S. arranensisand S. pseudofennica), could each consist of a set of geneticallyisolated clones reproducing by apomixis, with the possibilityin the case of S. pseudofennica of occasional genetic interchangeby sexual reproduction. The overlap of characters between the two hybrid groups suggeststhat the inflow of genetic material by hybridization and geneticmodification in these groups is continuing. Sorbus arranensis Hedl., Sorbus pseudofennica E. F. Warb., Sorbus aucuparia L., Sorbus rupicola (Syme) Hedl., interspecific hybridization, apomixis     

中国松毛虫属八个种和亚种亲缘关系的DNA指纹证据

利用DNA指纹谱方法探讨了中国松毛虫属8个种和亚种〔马尾松毛虫Dendrolimus punctatus punctatus (Walker),德昌松毛虫D. punctatus tehchangensis Tsai et Liu,文山松毛虫D. punctatus wenshanensis Tsai et Liu,思茅松毛虫D. kikuchii Matsumura,赤松毛虫D. spectabilis Butler,油松毛虫D. tabulaeformis Tsai et Liu,落叶松毛虫D. superans (Butler),云南松毛虫D. houi Lajonquiere之间的亲缘关系。13个随机引物在8种松毛虫中共检测到168个多态分子标记。分析表明,这8个种间的遗传距离的变化范围为0.3780～0.7360;马尾松毛虫与其亚种德昌松毛虫的遗传距离最近,为0.3780,与其另一亚种文山松毛虫以及油松毛虫的遗传距离次之,皆为0.5233;赤松毛虫、落叶松毛虫、云南松毛虫与马尾松毛虫的遗传距离则再次之,分别为0.6362,0.6770和0.6944;与马尾松毛虫遗传距离最远的是思茅松毛虫,为0.7360。8种松毛虫间具体的亲缘关系为: (D. superans (D. tabulaeformis (D. p. wenshanensis (D. p. tehchangensis, D. p. punctatus)(D. Kikuchii (D. spectabilis, D. houi))。     

Phytoplankton population dynamics in perennially ice-covered Lake Fryxell, Antarctica

Phytoplankton were collected over five austral summers (1987–88through 1991–92) to examine seasonal and annual fluctuationsin species composition and biovolume in Lake Fryxell, a perenniallyice-covered lake located in the Dry Valleys of South VictoriaLand, Antarctica. Lake Fryxell has perennial gradients of salinity,dissolved oxygen and nutrients. We found that algal speciesdiversity was low (56 taxa were collected), confirming the resultsof previous short-term studies. The phytoplankton consistedprimarily of cryptophyte and chlorophyte flagellates, and filamentouscyanobacteria. The presence of filamentous cyanobacteria, whichhave not been reported as abundant in this lake by previousworkers, may represent a significant ecological change. Eachaustral summer, one dominant species contributed >70% ofthe total biovolume; Chroomonas lacustris was dominant in 1987–88,while Cryptomonas sp. dominated the phytoplankton in the remaining4 years. No species succession occurred during the austral summer.Some common taxa were vertically stratified (Oscillatoria limnetica,Phormidium angustissimum, Pyramimonas sp., Oscillatoria sp.),while others showed no distinct vertical stratification (Chlamydomonassubcaudata, Cryptomonas sp.). The stratification of the phytoplanktonreflects the gradients of nutrients and light, and the stabilityof the water column.     

Seasonal variability in the relationship between body length and individual dry weight as related to food abundance and clutch size in two coexisting Daphnia species

Dry weights of individual Daphnia galeata and D. hyalina, whichcoexist in Lake Constance, were determined weekly during a twoyear investigation. From each sample and each species a length–weightrelationship (LWR) was calculated resulting in 54 (65) regressionequations based on N=2466 (3032) in D. galeata (D. hyalina).The constants (Ln(A)) and (B) of the LWRs showed a marked seasonalvariability, ranging from Ln(A)=1.0784–2.4740(1.0152–2.3860)and B=2.14–4.20 (2.11–4.15). The seasonal variabilityof the LWR was estimated with four different models. Condensingthe 54 (65) equations into one seasonal cycle resulted in amodel with an explained variance of r²=0.873 (0.869). Threemore models were established by calculating multiple regressionswith take stratification, average fecundity (E), and food concentrationas determining variates. Differences in LWRs of the two Daphniaspecies were significant (p <0.001). As the most useful approximationduring the period of stratification, LWRs are recommended forD. galeata: Ln(W)=(1.5674+0.0287^*(E))+Ln(L)^*(3.3611+0.0111^*(E)) as a generalized LWR for an epilimnetic daphnid, and for D.hyalina: Ln(W)=(1.5593+0.0613^*(E))+Ln(L)^*(3.2709+0.0017^*(E)) as LWR for a daphnid which migrates diurnally between epi andhypolimnion. The explained variance of this model is r²=0.843(0.826). The influence of food concentration in the epilimnionon LWRs was found to be significant on Ln(A) but not on (B). ^*This research project was supported by the Deutsche Forschungsgemeinschaft     

Changes in the structure of a zooplankton community during a Ceratium (dinoflagellate) bloom in a eutrophic fishless pond

The community structure of zooplankton was studied in a eutrophic,fishless Japanese pond. The ecosystem was dominated by a dinoflagellate,Ceratium hirundinella, two filter-feeding clado-cerans, Daphniarosea and Ceriodaphnia reticulata, and an invertebrate predator,the dipteran Chaoborus flavicans. The midsummer zooplanktoncommunity showed a large change in species composition (theDaphnia population crashed) when a heavy Ceratium bloom occurred.It is shown that (i) the rapid density decline of D.rosea inmid-May was mainly caused by a shortage of edible phytoplankton,which was facilitated by the rapid increase in Chirundinellaabundance; (ii) the low density of D.rosea in June-July wasconsidered to be mainly caused by the blooming of Ceratium hirundinella(which may inhibit the feeding process of D.rosea), while predationby Cflavicans larvae, the changing temperature, the interspecificcompetition and the scarcity of edible algae were not judgedto be important; (iii) the high summer biomass of the planktonicCflavicans larvae was maintained by the bloom of C.hirundinella,because >90% of the crop contents of C.flavicans larvae wereC.hirundinella during this period. The present study indicatesthat the large-sized cells or colonies of phytoplankton arenot only inedible by most cladocerans, but the selective effectof the blooming of these algae can also influence the compositionand dominance of the zooplankton community, especially for thefilter-feeding Cladocera, in a similar way as the selectivepredation by planktivorous fish. The large-sized phytoplanktoncan also be an important alternative food for ominivorous invertebratepredators such as Chaoborus larvae, and thus may affect theinteractions between these predators and their zooplanktonicprey. In this way, such phytoplankton may play a very importantrole in regulating the dynamics of the aquatic food web, andbecome a driving force in shaping the community structure ofzooplankton.     

Taxonomic Study of Linaria depauperata and L. supina Complexes in Eastern Spain

Morphological characteristics were studied in two groups ofclosely related taxa of sectionSupinae , Linaria depauperataand L. supina, from eastern Spain. Vegetative, floral and seedcharacteristics were of little use in distinguishing betweenthese taxa as the ranges for all the taxa studied overlapped.Flower colour could be used as a diagnostic character for somebut not all of these taxa. Seed coat characters were of hightaxonomic value, both when trying to distinguish among thesetwo groups, and the taxa included within them, and also whenestablishing relationships among the taxa studied. Some differenceswere found in the indumentum distribution and density. Threetypes of trichomes were identified, two of them eglandular andcommon to all taxa. The third type of trichome was a simplegland, that varied in the number of cells in the stalk and gland.Trichome length and wall width of stalk cells allowed severalgroups of taxa to be distinguished. Similarity relationshipsamong the samples studied are shown in a UPGMA phenogram. Accordingto these results, two new species, L. cardonica and L. sulphurea,are described. L. arabiniana is conspecific with L. depauperatasubsp. hegelmaieri. A key to identify the different taxa isprovided. Copyright 2001 Annals of Botany Company Scropulariaceae, Antirrhineae, taxonomy, morphological characters, seed-coat, trichomes, Linaria depauperata,Linaria supina