摘要:

Material of 85 species ofBrassicaand genera closely related to it was examined cytologically, and the chroiftosome counts are reported. These confirm records published by other workers for 42 species, two contradict earlier records, and 41 counts are believed to be new.Different species with the same chromosome number have been cross‐pollinated, and those found to be interfertile have been grouped into cytodemes. For the most part species found to be interfertile have long been regarded as closely akin, but three cases of interfertile intergeneric hybrids are reported.Altogether the material has been classified into 45 cytodemes: 35 diploids with chromosome numbers ranging fromn= 7 ton= 13, and 10 derived tetraploids. This enumeration is possibly not exhaustive of the world's genomes closely related to the crop Brassicas and a list is appended of the wild species which need examination before the enumeration might be considered to be complet

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00920.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Mitotic karyotypes of species ofColumneaL. sensu lato (Gesneriaceae) show morphological but not numerical differences in most cases. The differences are more exaggerated in continental species than in Jamaican ones. Changes in karyotype morphology have accompanied speciation, but the present limited karyotype data show no marked correlation with the geography or taxonomy of the species.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00921.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

SectionsNaevosaM. P. Chr.,CroceaM. P. Chr. andMacrodontaM. P. Chr. are reduced to subsectional rank in sectionSpectabiliaDahlst. of the genusTaraxacum.SectionArcticaDahlst. (sectionLaevia(Hand.‐Mazz.) Schischk.) is enlarged by including sectionsGlabraDahlst.,AntarcticaHand.‐Mazz. andPacherav. Soest.Taraxacum gurglenseA. J. Richards andT. unicoloratumA. J. Richards (sectionAlpestriav. Soest),T. concucullatumA. J. Richards (sectionCucullatav. Soest) andT. venticolaA. J. Richards (sectionVulgariaDahlst.) are described as new agamospecies from the Alps; andT. calcifhilumA. J. Richards&J. L. van Soest (sectionOrientaliaHand.‐Mazz.),T. nigricornisA. J. Richards (sectionMacrocomutav. Soest) andT. breviscapumA. J. Richards (sectionErythrocarpaHand.‐Mazz.) are described as new agamospecies from Afgh

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00922.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The karyotypes of 18 samples assigned to 13 agamospecies inTaraxacumare described. The species are classified among six sections;EiythrospermaLindb. f.,VulgariaDahlst.,Alpestriav. Soest,AlpinaHagl.,Fontanav. Soest andCucullatav. Soest, all from alpine localities in Europe. No previous cytological work is known for agamospecies in the last four sections.Two small chromosome types and the occurrence of accessory chromosomes are described for the first time inTaraxacum.Sibling karyotypes were found to be invariable, but extensive karyotypic variation was found between samples, even intraspecifically. Karyotypes were compared by means of a “karyotype similarity index”. Samples with a high overall similarity tended to have smaller chromosomes. Eight species exhibited regular chromosome sets, the remainder being irregular. The nature of the origin of the latter is discussed in relation to the origin of agamospecies in the ge

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00923.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

One hundred species of flowering plants are recorded from Kuwait and the Neutral Zone, north‐east Arabia. The records, which arise out of collections and observations made between 1961 and 1971, include 56 species not hitherto recorded, 17 previously recorded under different names and for which a revision of nomenclature seemed necessary, and 33 species with new distributional data within the study area. Six species are common to the last two categories, i.e. have both new names and new range

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00924.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

In a survey of the Leguminosae (167 species of 89 genera), calcium oxalate crystals were found in tapetal cells in all three subfamilies (84 species of 52 genera). Crystal form ranged from small scattered crystals to lens‐like to various large prismatic types, and included the first report of styloid crystals in the Caesalpinioideae. Over half of the caesalpinioid and papilionoid legumes examined had crystals. Crystals were not common in the Mimosoideae, however, but this may be because of the small sample. The distribution of species with various crystal types, and of species lacking crystals, did not reveal any patterns that conform to the presently defined taxa. Crystals in tapetal cells have previously been reported only in the Commelinaceae and Labiata

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00925.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

When grown for long periods in axenic single spore cultures, gametophytes of the four European species of subgenusHippochaeteare initially male or female. Females invariably produce antheridia as they get older, but archegonium formation by males is a much rarer event and was only observed inE. hyemaleandE. scirpoides.Male gametophytes are smaller, grow more slowly than the females and inE. hyemaleandE. variegatumare often short‐lived. The proportions of male and bisexual individuals are relatively constant within each species but vary between species. Likewise species differ in the rate at which females later produce antheridia. Gametophytes grow in three ways: activity of antheridial meristems which are totally committed to the formation of male tissues, activity of cushion meristems which may produce archegonia for an indefinite period or switch to antheridium formation, and proliferation from lamellae. Either archegonia or antheridia may arise on the adventitious branches resulting from lamellar proliferation, but the type of sex organ produced is strongly influenced by the culture medium, the sex and age of the parent tissue and the particular species in question. Only by this means are archegonia formed on initially male individuals. The sexual behaviour of the subgenusHippochaeteis compared in some detail with that of the subgenusEquisetumand several subgeneric characteristics are outline

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00926.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

A detailed investigation ofRodeitesSahni from nearly 100 specimens collected from the Deccan Intertrappean beds of India has brought to light some new important facts: (1) The sporocarp wall is thicker and the spores within it are larger than hitherto described. (2) The mode of sorus attachment, observed for the first time, is similar to that ofMarsilearather thanRegnellidium.(3) The presence of a distinct cellular gametophyte inside some megaspores is an entirely new finding for the family Marsileaceae. The presence of a male prothallus inside smaller microspores is also newly observed. (4) The occurrence of sporocarps in groups and their attachment are unique. (5) The prismatic layer is distinct in the sporocarp wall ofRodeitesThe above observations help in reconsidering the position ofRodeitesin the Marsileaceae.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00927.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

An account of 13 taxa in the genusEnteromorphaoccurring on the shores of the mainland of India is given. Of these, one,E. ovata, is a new species and another,E. linzavar.bicomuta, is a new variety. A key to the taxa is provided.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00928.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1972.tb00920a.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY