摘要:

Morphological evidence of hybridization and introgression betweenCrataegus orien–talisPallas ex M.–Bieb. and C.pycnolobaBoiss.&Heldr. in Boiss. was observed where the two species meet in the montane–subalpine zone of Mt Chelmos, Pelo–ponnisos.C. pycnolobavar.parnassicaDiap. is a variant ofC. orientalis.Greek and Yugoslavian material ofC. monogynaJacq.,C. curvisepalaLindm. and their hybrid is compared with Danish material of the three taxa using the multivariate techniques of discriminant analysis and Wells' distance coefficient. The infraspecific variation ofC. monogynaand the correct binary names forC. monogynaxorientalis(C.xalbanicaPojark. versus C. xpolyacanthaJan) andC. curvisepalaxmonogyna(C. xkyrtostylaFingerh.) are di

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01983.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01984.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The chemistry of the essential oil ofThymus praecoxOpiz ssp.arcticus(E. Durand) Jalas from Greenland was studied with the intention of comparing it with the results obtained earlier from Icelandic material. All the 17 samples collected at different localities of South–West Greenland were found to contain linalyl acetate as main component besides some sesquiterpene hydrocarbons and some oxygenated sesquiterpenes. The variable content of the sesquiterpene alcohols, nerolidol and hedycaryol in the essential oil gave reason to define four different chemotypes. The pattern of the chemotype characterizing compounds was identical with that of four of the seven chemotypes found earlier to be the most widely distributed in Iceland, namely chemotypes B, C, D, and F. No correlation between the occurrence of a certain type and special environmental conditions was found. That the essential oil chemistry and the appearance of polychemism in the GreenlandThymusplants accords so well with that of the Icelandic ones, indicates that the distance of nearly 300 km between Iceland and Greenland has not led to locally limited “chemical races” withinThymus praecoxssp.arcticus.These findings are contrary to the results obtained in some MediterraneanThymussp

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01985.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Seven species are recognized:Plantago pulvinataSpegazzini,P. uniglumisWalp.,P. sempervivoidesDusen,P. correaeRahn sp. nov.,P. tehuelchaSpegazzini,P. mooreiRahn sp. nov., andP. barbataG. Forster; the last with five subspecies: ssp.barbata;ssp.giganteaRahn ssp. nov.; ssp.austroandinaRahn ssp. nov.; ssp.monanthos(Dum. d'Urv.) Rahn stat. nov.; and ssp.muscoides(J. D. Hook.) Rahn stat. nov. 594 herbarium specimens from 399 collections have been studied and 61 collections cultivated. The chromosomes were counted in 56 of these: 2n = 23, 24, 48, 68, 72, and 96. Sympatric taxa usually occupy different ploidy levels. Populations with 2n = 48 of four subspecies ofP. barbataare separated geographically in Patagonia by ssp.barbatawith 2n = 72, which occupies the area between them. 846 cultivated plants and 312 herbarium collections have been measured. Numerical taxonomic methods were used, employing both sets of measurements. Statistics are used in keys and descriptions.

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01986.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01987.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

As a result of field work in Peru and Bolivia 1982–83, and herbarium studies, 21 new taxa are described and two new combinations are made inCalceolaria.The following species are described as new:C. sclerophylla, C. arbuscula, andC. crassaof sect.Sa–licifoliae; C. rupestrisof sect.Revolutae; C. micans, C. laevis, C. rariflora, and C.concavaof sect.Teucriifoliae; C. bullataandC. neglectaof sect.Parvifoliae; C. amoenaandC. ramosaof sect.Polyclada; C. pilosa, C. incana, C. hirsuta, and C.cordifoliaof sect.Urticopsis; C. cumbemayensisof sect.Lobatae;andC. caespitosaof sect.Scapiflorae.Three new subspecies are described:C. deflexaR.&P. ssp.cuneataandC. salicifoliaR.&P. ssp.nigricansof sect.Salicifoliae, andC. hispidaBenth. ssp.acaulisof sect.Lobatae.Two new combinations are proposed: C.melissifoliaBenth. ssp.pseudoscabra(Edwin) Molau of sect.Teucriifoliae, andC. llamaensis(Edwin) Molau of sect.Anacyrta.The taxonRevolutaeis raised to the sectional level, and the sectionsPolycladaandParvifoliaeare emendated. Chromosome numbers are reported forC. sclerophylla(2n = 36),C. micans(2n = 72),C. laevis(2n = 72),C. melissifoliassp.pseudoscabra(2n = 36),C. neglecta(2n = 36), C.cumbemayensis(2n = 36), andC. hispidassp.acaulis(2n =

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01988.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Finds of pollen and macrofossils ofRhamnus frangulaL. from Eem and Holocene are discussed and compared with the present pollen production and dispersal of the species, and its present distribution. It is presumed that there was little difference between the potential distribution area ofR. frangulaand its actual geographical range because of its rapid spread during Preboreal and Boreal in South Norway. A small, temporary expansion ofR. frangulaoccurred around 5 500 BP in a mountain valley in W Norway. A simultaneous local expansion of the species has been registered in Vestvågøy, Nordland county, N Norway. In these two areas, which are outside its present distribution, the maximum ofR. frangulais dated to between 5 000 and 4 800 BP. The maxima ofR. frangulain profiles from other Norwegian areas are discussed. Factors such as changes in climatic condition, in–filling stages of local successions in the sedimentation basins, or human activity may explain the differences fo

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01989.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A histochemical study was made of developing sporogenous cells, meiocytes, microspores, pollen and the tapetum in anthers ofKalanchoë morlagei.Storage polysaccharides were seen only in mature pollen. Ascorbic acid was not found in the sporogenous cells, but in meiocytes a high quantity of this compound occurred in the cytoplasm. Spore tetrads, microspores and pollen also had a high ascorbic acid content. The amounts of RNA and proteins were high in the sporogenous cells and in meiocytes during meiosis–I, but a small reduction trend with respect to RNA content was noticed. Microspores in the tetrad showed high amounts of RNA and proteins. In the young microspores RNA and proteins declined. Later, as the microspores matured, an increase in content of RNA and proteins took place. The wall of the young microspores gave a faint green colour with azure B stain, the intensity of which increased and remained high in the exine of the mature pollen. The additional wall thickening around the meiocytes and tetrads gave a strong pink colour with PAS test. This thickening showed presence of silver granules when tested for ascorbic acid, the tapetum synthesized abundant quantities of PAS positive starch, ascorbic acid, RNA and proteins from its appearance in the anther wall until microspore formation. During meiocyte meiosis the tapetum became highly vesicular. Our results indicate that the tapetum constitutes a tissue specialized for storing and supplying basic nutritive substances for the developing pollen in the anth

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01990.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01991.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Dry seeds ofCuscuta pedicellatahave a deeply pitted surface due to invaginated epidermal cell walls. After water uptake these walls bulge outwards and the seed surface becomes papillose. The seed coat consists of an epidermis, two palissade cell layers, and a multiple layer of parenchyma cells. The epidermis contains starch and mucilage, the parenchyma cells are compressed but some contain starch. The endosperm consists of starch–filled cells, but has a peripheral aleuron layer. The endosperm cell walls are gelatinous. The variable structure of the seed coat epidermis is believed to function in wind dispersal and rapid water uptake. Seed dormancy is common in the genus, but does apparently not occur inC. pedicellat

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1984.tb01992.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY