摘要:

As a result of a renewed search in the historical locality ofSpartina x neyrautiithis taxon was rediscovered on the Atlantic seaboard of northern Spain in 1970. Cytological study has subsequently demonstrated its hybrid nature, the same chromosome number asS. x townsendiiand probable similar parentage. However, it is significantly different in chromosome analysis and chiasma frequency. This, along with minor morphological deviations, suggests a different genotype and denotes it as a separate taxon, possibly of reciprocal parentage.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01182.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Taxonomy of six species ofChlorophytum(Liliaceae) from India has been reassessed in the light of their morphological and cytological characters.C. tuberosum(Roxb.) Baker (2n= 16), a wide‐spread species, is morphologically well defined butC. bharuchaeAnsari, Raghavan&Hemadri (2n= 16) has been confused withC. glaucumDalz. andC. glaucoidesBlatter (both 2n= 42) by earlier workers.C. malabaricumBaker (2n= 42) is a delicate species and occurs in the Nilgiris and the Western ghats. Two closely allied species,C. nepalense(Lindley) Baker andC. khasianumHooker fil. (both 2n= 56) are distributed in Eastern India. The first two species, with 2n= 16, have been considered as at the diploid level with base number 8 while the rest of them appear to be autoallopolyploids with base number

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01183.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The morphology of twelve species ofRosais described and similarities between these species are assessed. Possible origins of the tetraploid species from diploid species are indicated on grounds of comparative morphology.The wild origins of living and herbarium specimens are given in order to supplement published data on geographical distribution.Meiosis in pollen mother cells, viability of pollen grains at anthesis and ability to set seed was studied in several F1hybrids: no indication of complete or even partial sterility was found. Reproductive isolation is therefore unlikely to be maintained by reduced fertility of interspecific hybrids.Three species are reduced to synonymy with three other species, being retained as subspecific taxa. Two species are transferred from sectionPimpinellifoliaeto sectionCinnamomeae.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01184.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

A brief outline is given of the history and nomenclature of the sexual and graft hybrids (chimeras) betweenCrataegusandMespilus.An investigation has been made of some aspects of the macromorphology, the pollen fertility and exine characters, cytology and physiology of the plants growing in the Royal Botanic Gardens, Kew. It is suggested that in the past too much emphasis has been laid on the anatomy of the epidermal layers and the separation of parental characters in chimeras. Observations made during the study show the presence of intermediate characters in the graft hybrid as well as in the sexual hybrid and there is evidence that most parts of the graft hybrids are probably influenced by both the parental genotypes.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01185.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Three genera of the Uvularieae(Kreysigia, Schelhammera, Uvularia)have tricarpellate, syncarpous pistils. Ventral bundles (presumably the united simple septal and placental bundles of a carpellary wing) may be present inKreysigiaandSchelhammera.InKreysigiathe two presumptive ventral bundles from adjoining carpels are fused basipetally in each septum. The septal bundles of the other two genera are either simple(Schelhammera)or in part compound (united) below and simple (separate) above(Uvularia), hence fused acropetally. InUvularia, the dorsal bundle of the carpel and the median bundle of the tepal are uniquely tripartite and probably homologous. No raphides were found in the carpels of these genera.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01186.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Lateral phylloclades ofRuscus aculeatusare found in the axils of reduced scale leaves on the orthotropic, photosynthetic stem. The terminal phylloclade results from the elongation and flattening of the main shoot apex after the lateral appendages have been initiated. Studies of the development of both lateral and terminal phylloclades point to their cauline nature. The hypothesis that the phylloclade results from the congenital fusion of a reduced short shoot and its prophyll is not supported.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1977.tb01187.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY