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1.
Kerry Barringer 《Brittonia》1991,43(4):240-252
Epidendrum subgenusEpidanthus (L. O. Williams) Barringer (Orchidaceae) is a group of small, slender-stemmed epiphytes formerly classified in the genusEpidanthus L. O. Williams. The seven species are distributed from southern Mexico to Columbia in wet forests, usually above 1000 m in elevation. Species of subgenusEpidanthus are distinguished from the rest ofEpidendrum by their linear leaves, slender stems, and two pollinia. The new speciesEpidendrum aurigineum is described and the new nameEpidendrum, insolatum is created forE. crassum (Dressler) Mora-Retana & J. García.  相似文献   

2.
Oryza schlechteri has only recently been rediscovered in Papua New Guinea. This species is quite distinct from otherOryza species but resembles closely related genusLeersia in its small panicle and profusely spreading habit. On the basis of spikelet morphology that has previously been used to distinguishLeersia andOryza species,O. schlechteri was compared withO. brachyantha. O. longiglumis, O. sativa, L. perrieri, L. tisseranti, andL. hexandra to clarify its generic position. Results corroborate that the presence of a sterile lemma and a striated spikelet epidermal (abaxial) surface lacking siliceous triads inO. schlechteri allies this species with otherOryza species rather than withLeersia.  相似文献   

3.
Sixteen new species are proposed in the generaAckermania, Dressleria, Epidendrum, Maxillaria, Oncidium, Rodriguezia, Sigmatostalix, andTrigonidium. All new species are illustrated.Maxillaria vittariifolia L. O. Williams is newly recorded for Peru. A key is provided forTrigonidium of Peru.Trigonidium loretoense Schltr. andT. peruvianum Schltr. are lectotypified.  相似文献   

4.
The tandemly repeated multigene families encoding 18S and 25S rRNAs were studied at the restriction enzyme level inPopulus alba L.,Populus deltoides Bartr. exMarsh.,Populus trichocarpa Torr. & Gray and in the hybrids between the last two mentioned species. The analysis of single and double digestion with EcoRI, BamHI, XbaI, and SstI endonucleases showed the presence of single repetitive unit types of 12.25 and 11.75kb inP. alba andP. trichocarpa, respectively.P. deltoides showed two rDNA gene types having the same length (12.25Kb) but different nucleotide sequence in the IGS. The rDNAs genes ofP. deltoides andP. triochocarpa are inherited codominantly in their hybrids.  相似文献   

5.
Primula domensis Kass & S. L. Welsh,P. maguirei L. O. Williams, andP. nevadensis N. H. Holmgren are reduced to varietal status underP. cusickiana (A. Gray) A. Gray.  相似文献   

6.
The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.  相似文献   

7.
Claes Persson 《Brittonia》2003,55(2):176-201
Agouticarpa, a new genus of the informalAlibertia group (Rubiaceae), is described and illustrated. It comprises six species, and occurs from Costa Rica to Bolivia. Three species are here described as new:Agouticarpa grandistipula, A. hirsuta, andA. velutina. Additionally, three new combinations are made:A. curvifolia andA. williamsii (previously inGenipa) andA. isernii (previously inAlibertia). Agouticarpa is characterized by being dioecious, having elliptic to abovate, membranaceous stipules, male flowers in a branched dichasial or thyrse-like inflorescence, a poorly developed cup-shaped calyx, pollen grains with 3–7 apertures, and large globose fruits.  相似文献   

8.
Atlantic salmon,Salmo salar L., from four European locations show allelic variation at one of three triose-phosphate isomerase (TPI) loci (TPI-3*) when separated on horizontal starch gel electrophoresis, using either eye or liver extracts. Two common alleles (*100 and*103) and one rare allele (*97) segregate atTPI-3* with unambiguous typing being possible by observing the interlocus heterodimers. Family studies demonstrate thatTPI-3* 100 and*103 are of autosomal location and are inherited in a Mendelian fashion.TPI-3* variation can also be typed in adipose fin tissue, allowing nondestructive tissue sampling. Three loci are also active in brown trout,Salmo trutta, with two individuals being homozygous forTPI-3*, as are a small number ofS. salar from eastern Canada. The presence of this additional variable allozyme locus inS. salar is important, since genetic studies in that species have been limited by the low level of allozyme variability detectable.  相似文献   

9.
The formation of sperm cells has been examined ultrastructurally in the tricellular pollen grains ofGalium mollugo L. (Rubiaceae).Trichodiadema setuliferum Schwantes (Aizoaceae), andAvena sativa L. (Poaceae). After detachement from the intine the generative cell of all three species lies free within the vegetative cytoplasm. The two sperm cells are built inTrichodiadema andAvena by a single separating wall, while inGalium mollugo two independent walls are formed. However, both mechanisms separate the two male gametes completely.  相似文献   

10.
Parasitism ofLygus lineolaris (Palisot de Beauvois) eggs by three species ofMymaridae, Anaphes iole Girault,Erythmelus miridiphagus Dozier andPolynema pratensiphagum Walley and one species ofScelionidae, Telenomus sp., was investigated at Ste-Anne-de-Bellevue, Québec. The maximum level of field parasitism ofL. lineolaris eggs by individual species was 15.4, 53.8, 70.0 and 16,7%, respectively. Parasitoids were retrieved from eggs ofL. lineolaris inserted in stems and branches ofAmaranthus retroflexus L.,Chenopodium album L.,Coronilla varia L.,Rumex obtusifolius L. andSolanum tuberosum L. Amaranthus retroflexus andS. tuberosum sustained a large population ofL. lineolaris and egg parasitism was high enough to consider it as a potential control factor.   相似文献   

11.
The 16 species of theSedum acre-group were investigated for the presence of alkaloids. They areS. acre ofS. ser.Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, andS. urvillei ofS. ser.Alpestria, S. samium ofS. ser.Samia, andS. litoreum ofS. ser.Litorea. S. acre differs significantly from the other species. It contains sedamine, hydroxy sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species ofS. ser.Alpestria, S. ser.Samia, andS. ser.Litorea contain 4 piperidine alkaloids which also occur inS. acre, and in addition 4 pyrrolidine alkaloids not present inS. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia).  相似文献   

12.
Three new species of Myrtaceae (Calyptranthes bracteata, Eugenia gonglycocarpa, andMyrcia rupta) from northeastern South America are described and illustrated, and a new combination (Eugenia tetramera) is proposed. The closed-calyx and the completely or partially fused cotyledons ofMyrcia rupta, unusual features for the genus, are discussed and compared with related species inMyrcia andMarlierea.  相似文献   

13.
We have used total genomic DNA as a probe to size-fractionated restriction enzyme digests of genomic DNA from a range ofTriticeae species from the generaLeymus Hochst.,Psathyrostachys Nevski, andHordeum L., and hybrids betweenHordeum andLeymus to investigate their taxonomic relationships. Genomic Southern hybridization was found to be an effective and simple way to assess the distribution and diversity of essentially species-specific and common, repetitive DNA sequences, and is hence especially useful in evolutionary studies. The DNA sequences ofH. vulgare seem to diverge substantially from those ofH. brachyantherum, H. lechleri, H. procerum, andH. depressum. The genome ofThinopyron bessarabicum shows little homology to those of theLeymus species investigated, confirming thatT. bessarabicum is not an ancestral genome inLeymus. Although the genomes ofLeymus andPsathyrostachys share substantial proportions of DNA sequences, they include divergent repeated sequences as well. Hybridization with a ribosomal DNA probe (pTa 71) showed that the coding regions containing structural genes encoding the 18 S, 5.8 S, and 26 S ribosomal RNA were conserved among the species investigated, whereas the intergenic spacer region was more variable, presenting different sizes of restriction fragments and enabling a classification of the species. The rye heterochromatin probe pSc 119.2 hybridized to DNA fromH. lechleri andT. bessarabicum, but not to DNA from the other species investigated.  相似文献   

14.
The two species of the genusBrimeura (Liliaceae),B. amethystina andB. fastigiata, show a strikingly disjunct geographical distribution. Both species have a bimodal chromosome complement, 2n = 28, which includes 10 large (L) and 18 small (S) chromosomes. Most of the L-chromosomes possess heterochromatic segments which show enhanced quinacrine fluorescence. The resulting banding patterns are species-specific. Two triploid plants have been found inB. fastigiata.  相似文献   

15.
Seventy populations of North American annualMicroseris, Stebbinsoseris, andUropappus species were examined for chloroplast and nuclear ribosomal DNA restriction site variability to determine the origin of the allotetraploid speciesS. heterocarpa andS. decipiens. Previously identified chloroplast DNA restriction site variants were used in concert with restriction site variation forNco I in the nuclear-encoded ribosomal DNA repeat. The presence of two, mutually exclusive restriction site gains were observed in diploid populations ofM. douglasii; these same variants were also found in populations of allotetraploidS. heterocarpa, indicating mutiple origins of this species from different maternal diploid populations ofM. douglasii. Variation in the rDNA repeat between the diploid annual species and the putative paternal genome ofU. lindleyi was found to be additive inS. heterocarpa. A similar relationship was observed for the origin ofS. decipiens; cpDNA restriction site variants found inM. bigelovii andM. douglasii were present inS. decipiens. The rDNANco I variants also were additive in this purported allotetraploid. These results confirm the reticulate evolutionary pattern inStebbinsoseris and provide another example of multiple origins of intergeneric allopolyploids.  相似文献   

16.
In the Iberian Peninsula and Balearic Islands pollen dimorphism was found inTeucrium fruticans L.,T. pseudochamaepitys L., andT. rotundifolium Schreber. Generally, this dimorphism shows two sizes of pollen grains, the smaller more or less collapsed. The percentage of pollen viability is calculated. Differences in size between viable and nonviable pollen grains are similar, being about 40% inT. fruticans andT. pseudochamaepitys, and about 26% inT. rotundifolium. With regard to pollen viability, the percentage of male sterility is higher inT. fruticans, in which from male sterile (ms) plants, 100% nonviable pollen was obtained from every flower observed. InT. pseudochamaepitys andT. rotundifolium with rare exceptions, the percentage of nonviable pollen does not seem to be significant.  相似文献   

17.
Scilla persica and 5 species of the so-calledS. hohenackeri group, namely,S. furseorum, S. puschkinioides, S. vvedenskyi, S. hohenackeri, andS. greilhuberi, have been investigated embryologically with special reference to embryo sac and endosperm development.Polygonum-type embryo sac development was stated inS. puschkinioides andS. greilhuberi. 8-nucleate, normally structured embryo sacs, which could not be specified further due to sparse availability of the material, were stated inS. furseorum, S. vvedenskyi, andS. hohenackeri. InS. persica the embryo sac develops according to the bisporicAllium-type. In most species endosperm development was stated to be nuclear, exceptS. hohenackeri, where the type could not be specified. Other traits of possible taxonomic significance are the number of layers in the outer integument, which is mostly 4, or 5–6 inS. furseorum, and the occurrence of polyploid versus haploid and early degenerating antipodal nuclei, the latter occurring only inS. persica andS. furseorum. These embryological characters may be useful for assessing taxonomic relationship of the present species with other allied groups withinScilla, in particular, theS. siberica alliance,S. messeniaca, and theS. bifolia alliance. TheAllium-type embryo sac, which occurs inS. persica, is also characteristic for theS. siberica alliance, and may be a common derived character. Lack of antipodal polyploidization, as characteristic forS. persica andS. furseorum, occurs also in theS. siberica alliance, and is perhaps another common derived trait indicating phylogenetic relationship. Nuclear endosperm development is more frequent in spring-flowering squills than helobial development, which has previously been stated inS. messeniaca, some species of theS. siberica alliance, and inS. litardierei. While helobial endosperm may be primitive forHyacinthaceae in general, it may, by reversal, also occur as a derived character, at least in some species of theS. siberica alliance.  相似文献   

18.
In a chemotaxonomic study of the genusSymphytum pyrrolizidine alkaloids and triterpenes were used as chemotaxonomical markers. A micro-extraction methods was developed for screening compounds of very small pieces of herbarium material. The occurrence of the pyrrolizidine alkaloids symphytine and (acetyl-)lycopsamine is very general forSymphytum taxa. Echimidine is present in someS. officinale L. plants and inS. tanaicense Steven. The triterpene isobauerenol is present inS. officinale, S. bohemicum Schmidt,S. tanaicense and inS. officinale var.lanceolatum Weinm. The chemotaxonomic hypothesis, proposed byGadella and collaborators, based on the presence of the triterpene isobauerenol inS. officinale and its absence inS. asperum Lepech. and the presence of the pyrrolizidine alkaloid echimidine inS. asperum and its absence inS. officinale, can no longer be applied absolutely to theS. officinale species complex. The pyrrolizidine alkaloid and triterpene pattern ofS. officinale (2n = 24) andS. bohemicum (2n = 24) is identical.S. bohemicum is morphologically, cytologically and phytochemically very similar toS. officinale. Furthermore, it readily crosses with the white flowered W. European diploids ofS. officinale. Therefore it seems likely that these two taxa are conspecific.S. tanaicense shows a pyrrolizidine alkaloid and triterpene pattern similar toS. officinale (2n = 40). Also on morphological and cytological grounds they are very similar. It seems highly probable thatS. tanaicense is conspecific withS. officinale (2n = 40) and represents an intraspecific variant only.S. officinale var.lanceolatum contained no pyrrolizidine alkaloids but did contain isobauerenol. This feature points to an origin fromS. officinale.  相似文献   

19.
The genetic frequencies of 9 isozyme loci have been estimated in 23 samples of 4 species ofSecale by means of starch gel electrophoresis. The populations ofS. silvestre andS. vavilovii were monomorphic and uniform within each species, those ofS. montanum andS. cereale were polymorphic for most of the isozyme loci. On the basis of isozyme patterns as well as allelic and genotypic frequencies of isozyme loci,S. silvestre can be distinguished fromS. vavilovii, and both fromS. cereale andS. montanum; but there is no clear differentiation between the two latter species. Clusters constructed from genetic distances separateS. silvestre andS. vavilovii, whereasS. cereale andS. montanum were grouped together. The isozymatic data presented here, along with cytogenetic and life habit data, agree with the generally admitted existence of 4 species inSecale, and support the relationships suggested byKhush & Stebbins (1961).  相似文献   

20.
Significant relationships between the emergence of adult predatory species,Ophyra aenescens (Wiedemann) andMuscina stabulans (Fallen) and prey,Musca domestica L.,Fannia femoralis (Stein) andF. canicularis (L.) existed on 10 poultry ranches in southern California. Predatory species may function in natural control at intervals throughout the year, especially on predominant prey,F. femoralis andF. canicularis. Dipterous species, especiallyO. aenescens andF. femoralis, were only moderately influenced by the surface area of breeding habitat available. Accuracy in the measurement of population trends in Diptere may be enhanced by increasing the number of samples at any given ranch rather than the addition of study ranches. Parasitism, ranging from 22.6–37.8% of collected puparia, involved principally 3 species,Muscidifurax zaraptor Kogan & Legner,M. raptor Girault & Sanders andSpalangia cameroni Perkins.   相似文献   

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