摘要:

From decussation to distichy, with some comments on current theories of phyllotaxy. An instance of the rare spontaneous phyllotactic change from decussate to alternate distichous involving fusion of whorled primordia is described inSymphoricarpos albusvar.laevigatus, a phenomenon experimentally induced earlier inStellaria media.Attention is called to the occurrence at the beginning or end of such changes, both spontaneous and experimentally induced, of leaves directly superimposed on the same orthostichy. This appears to put most current theories of phyllotaxy in question, as instead of arising as far as possible from the next older primordia, a primordium is initiated as close as possible to the preceding one.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00980.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Systematic wood anatomy of the tribe Guettardeae (Rubiaceae). The wood anatomy of nearly all genera of the Guettardeae (Rubiaceae, Guettardoideae) has been examined, and in this respect the tribe is heterogeneous. Suggestions are made for a delimitation of the tribe.Guettarda, Bobea, Antirhea, MalaneaandChomeliaJacq. are sufficiently similar in their wood anatomical characters to warrant retention in the same tribe.Machaonia, TimoniusandDichilantheare anomalous. Suggestions are given for taxonomic revisions of some genera based on their wood anatomy.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00981.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Anatomy of the endophyte ofViscum albumL. (Loranthaceae). An anatomical investigation into the nature of the host‐parasite interaction ofV. albumand several of its phanerogamic hosts using SEM and light microscopy was conducted. Three kinds of parasite cell (haustorial parenchyma cells, cells resembling transfer cells and haustorial tracheids) were identified at the host‐parasite interface. The terms haustorial parenchyma and haustorial tracheid are defined. Haustorial tracheids were seen to have penetrated the walls of host vessel elements and it is suggested thatV. albumis able to establish on a wide range of hosts because of the anatomically plastic nature of its haustorium. The development of the haustorium depends to a large extent on the nature of the surrounding host tissues. Parasite‐induced host abnormalities including hypertrophy, distorted xylem elements, vessel‐wall penetration and tylosis‐occluded vessels were observed. The macroanatomical features observed are discussed and interpreted by‐proposing a new theory for the ontogenesis of theV. albumhaustorium. Cortical strands with ‘chisel’ and ‘pencil’ shaped apices were both found to be present at the same time on one plant and thus were not s

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00982.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A taxonomic clarification ofPetrorhagiasectionKohlrauschia(Caryophyllaceae). The morphology of the inflorescence bracts and seeds inPetrorhagia glumaceaand the large‐flowered form ofP. ‘prolifera’is reported together with observations on some artificially produced hybrids.Petorhagia glumaceaand large‐floweredp. ‘prolifera’can be distinguished on the basis of bract and seed morphology. The taxonomic status of large‐floweredP. ‘prolifera’is recognized asP. obcordata.Two groups of intermediate, natural populations are described from the Peloponnese and it is suggested that they are of hybrid origin. The seeds ofP. obcordataare polytypic and show a geographical distribution pattern. Seed morphology, which is the most useful diagnostic character for identification, is described inP. prolifera, P. velutinaand the tetrap

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00983.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Pachyphragma macrophyllutn(Hoffm.) Busch (Cruciferae), a Caucasian species naturalized in Co. Avon, England.Pachyphragma macrophyllum(Hoffm). Busch (Cruciferae) has been naturalized near Bristol for a number of years. An account of this colony and a full description of the species, including features that have been overlooked in the literature, is given and a chromosome count of 2n= 14 is reported. The taxonomic status ofPachyphragmais discussed,vis‐à‐vis Thl

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00984.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Contribution à la cytotaxonomie del'Amelanchier ovalisMedikus (Rosaceae). The widely distributed European speciesAmelanchier ovalisMedikus (syn.Mespilus amelanchierL.) consists of a diploid population (2n= 34) and a tetraploid one (2n= 68) diverging quantitatively in size of leaf and length of pedicels, petals and seeds. The nameA. ovalisis here typified by a specimen (L.H. 646.11) in the Linnaean Herbarium which represents the diploid population. The tetraploid population is here namedA. ovalissubsp.embergeriFavarger&Stearn. Their cytology, distribution and nomenclature are discussed.RÉSUMÉL'espèceAmelanchier ovalisMedikus (Syn.Mespilus amelanchierL.), largement distribuée en Europe, comprend une race diploǐde (2n= 34) et une race tétraploǐde (2n= 68). Celles‐ci diffèrent l'une de l'autre par des caractères quantitatifs (taille des feuilles, longuer des pédicelles, des pétales et des graines). Le nomA. ovalisest typifié ici‐même par un specimen (L.H. 646.11) de l'Herbier de Linné qui représents le cytotype diploǐde. Le cytotype tétraploǐde est nommé ici:A. ovalissubsp.embergeriFavarger et Stearn. Les caractères cytologiques, la distribution et la nomenclature des deux so

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00985.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1983.tb00980a.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY