摘要:

RASMUSSEN, F. N., 1985.The gynostemium of Bulbophyllum ecornutum (J. J. Smith) J.J. Smith (Orchidaceae). Stages in the development of the gynostemium ofBulbophyllum ecornutumdemonstrate that the pollinium stalk is a hamulus in this and in a closely related species,B. gibbolabium. A hamulus arises by apical growth and reflexion of the median carpel. Hamuli have recently been discovered in several orchid genera, and a transverse fold of the rostellar apex is already known from a large group of orchids. The closely relatedB. cornutumhas a quite different gynostemium structure.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01014.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

STERN, W. L., PRIDGEON, A. M.&LUER, C. A., 1985.Stem structure and its bearing on the systematics of Pleurothallidinae (Orchidaceae). Pleurothallids comprise a subtribe of numerous orchids consisting of mostly diminutive New World epiphytes. The cauline system involves a branching rhizome bearing unifoliate ramicauls. The inflorescence usually originates from an adaxial invagination toward the apex of the ramicaul. Two or more cycles of vascular bundles traverse the ramicaul; typically, there is an outer, branching series of smaller strands and an inner, non‐branching series of larger strands. In the ultimate internode subtending the leaf the smaller, outer bundles migrate between the larger, inner bundles and become aggregated in the medullary region. They bend adaxially to vascularize the inflorescence. The leaf is articulated at an abscission layer to the prolongated apex of the ramicaul more or less distal to the cauline invagination. In some pleurothallids, a cauline annulus appears at the insertion of the inflorescence and cither below or at the attachment of the leaf to the apex of the ramicaul. Anatomical studies show that the annulus is the external manifestation of an intercalary meristem. Except forPleurothallis, genera are consistent in having or lacking an annulus. Genera with two pollinia either possess or lack the annulus; those with four to eight pollinia always lack the annulus. It is suggested that the intercalary meristem is a derived characteristic providing survival value and a selective advantage to those pleurothallids in which it occurs. Presence of the intercalary meristem is correlated with other structural features considered to represent specialization

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01015.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

NICHOLLS, M. S., 1985.A systematic study of the Linum tenuifolium group (Linaceae). A new classification of theLinum tenuifoliumgroup is presented based upon detailed systematic study of 74 populations in nature. Previous confusion over taxonomy and nomenclature is resolved.Linum salsoloides, L. appressumandL. suffruticosumare treated as subspecies ofL. tenuifolium. The morphological variation within each subspecies is discussed with reference to its distribution.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01016.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

LOVELESS, A. R., 1985.The occurrence of ergot fungi (Clavicipitales) on the genusHyparrheniain southern Africa. In southern Africa the presence of ergots has been confirmed on 11 wild grasses of the genusHyparrhenia. Two species ofClavicepsare involved. One of them has predominantly triangular conidia, and is therefore identified asC. pusilla. The other has very characteristic truncate conidia, and is either an undescribed species orC. inconspicua, depending upon how problems in the identification of species ofClavicepsare to be resolved. OnHyparrhenia, C. pusillais restricted to species belonging to the series Cymbariae, and the undetermined species ofClavicepsinfects various species ofHyparrheniabelonging to at least four other series of the genus.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01017.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SKIDMORE, D. I.&INGRAM, D. S., 1985.Conidial morphology and the specialization ofBremia lactucaeRegel (Peronosporaceae) on hosts in the family Compositae. Conidia ofBremia lactucaewere collected fromLactuca saliva, Sonchus oleraceus, S. asper, Senecio vulgaris, S. bicolorsubsp.cineraria, Cirsium arvense, Centaurea nigraandPicris hieracioides, from a wide distribution in the British Isles. There were no consistent differences between isolates taken from the different hosts in the lengths, breadths or length: breadth ratios of the conidia, the lengths of the conidiophores or the numbers of sterigmata per conidiophorc branch. Therefore, as there are no significant morphological differences between the isolates ofBremia lactucaefrom these hosts, the pathogen is classified upon host specialization. A review is presented of cross‐infection studies in which isolates ofB. lactucaehad been inoculated on to a range of species of Compositae. On the basis of these investigations it is recommended that the term ‘formae speciales’ is used to denote host specialization of isolates within the speciesBremia lac

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01018.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1985.tb01014a.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY