摘要:

A total of 241 intergeneric combinations betweenHordeumandSecalewere attempted. It was only possible to obtain hybrid offspring from combinations withHordeumas the female parent. By the aid of embryo culture technique 81 intergeneric combinations were synthesized, 72 of them not reported earlier. Generally hybridization with the polyploid species ofHordeumwas most successful. Morphologically the hybrids were intermediate to the parents in most characters, though an obvious effect of genome dosage could be observed. Only few deviations from the expected chromosome numbers of the hybrids were found. All hybrid plants showed complete male sterility.

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01404.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Eremopyrum(tribe Triticeae) is revised and 4 species are recognized:E. triticeum(2n = 14),E. orientate(2n = 28),E. distans(2n = 14) andE. bonaepartis(2n = 14,28). A key and maps showing the distribution of the species are presented. The relationships withinEremopyrum, including the origin of the tetraploids, and the relationships betweenEremopyrumand other genera of the Triticeae are discussed.

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01405.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01406.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Names of sixtyone taxa described by G. Wahlenberg based on Nordic material are typified. An additional four are listed but no type material is traced. Wahlenberg's four journeys and various modifications of his handwriting are presented. Flora nordica notes no. 4

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01407.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The genusCalotropisof the tribe Asclepiadeae of Asclepiadaceae subfamily Ascle‐piadoideae is revised throughout its Tange in tropical and subtropical Africa and Asia. The three species recognized are keyed out, illustrated and described with appropriate bibliography, synonymy, notes on ecology, distribution and uses. Distribution maps for the species are provided. The taxonomic position of the genus is discussed and a historical review is provide

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01408.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Atriplex griffithiiis divided into two subspecies, ssp.griffithiiand ssp.stocksii, stat. nov.Atriplex farinosais typified and divided into two subspecies, ssp.farinosaand ssp.keniensis, stat. nov. A new species ofAtriplex, A. nogalensisis described from Somalia. The subtribe Sevadinae is revised and found to consist of the two monotypic generaSevadaandFadeniaand the genusLagenanthawith two species,L. cycloptera, comb. nov. (which includes the types ofGyropteraandCycloptera), andL. gillettii, comb. nov.

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01409.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A study of the variation within the tropical African taxonTrifolium burchellianumssp.johnstonii, including var.oblongum, is made on the basis of herbarium material and cultivated material. The chromosome numbers 2n = 48 and 2n = 96 were counted in the collections of var.johnstoniiand var.oblongumrespectively. In most other material, the chromosome number has been estimated from the size of the pollen grains and guard cells. Var.johnstoniiwas found to have both 2n = 48 and 2n = 96 and var.oblongumwas found only to have 2n = 96. Var.oblongumand var.johnstoniiwith 2n = 96 are found to have complementary distributions, while the distribution of var.johnstoniiwith 2n = 48 is found sympatric with all the 2n = 96 material. The sterility barriers are persumed to have become weakened at the higher ploidy level, and gene flow is presumed to explain the continuous variation between the two varieties. The origin of var.oblongumis also discussed.

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01410.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01411.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Two new species ofChusquea, C. albilanatafrom Colombia and Ecuador, andC. repensfrom Mexico, are described and illustrated; two subspecies are recognized withinC. repens.A complete description ofC. lehmannii, a common species of the upper montane forests and subpáramos in southern Colombia and Ecuador, is provided, and two subspecies are formally recognized.Guadua velutinafrom central and eastern Mexico is described and illustrated; this species represents the northernmost extension of the genus

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01412.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The phloem of the Myristicaceae is composed of sieve elements, parenchymatous cells, and fibers. Within the metaphloem and secondary phloem parenchymatic layers including prominent secretory elements alternate with tangential bands of fibers and layers composed of sieve elements, companion cells and phloem‐parenchyma cells. among the latter the sieve elements are most abundant and easily identified by the presence of thick (nacreous) walls. The most characteristic feature of the sieve elements of Myristicaceae (and found nowhere else among the Magnoliiflorae) are nuclear crystals, which are released into the lumen during nuclear degeneration and persist in the mature cell. P‐and S‐type sieve‐element plastids were recorded for the 18 species investigated. Both types of the plastid are characterized by large diameters and many medium‐sized starch grains. The sizes and contents (small protein crystals only) of the P‐type plastids of the Myristicaceae do not conform to the tiny P‐type plastids (with large protein crystals) of the Annonaceae, a family to which the Myristicaceae is traditi

ISSN:0107-055X    

DOI:10.1111/j.1756-1051.1991.tb01413.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY