Hurst's Septet Scheme

Hurst: Septet Formulae

Hurst: Septet TraitsHurst: Septet Traits in Columns

Septets and Styles

Hurst: Origin of the Moss Rose (1921)

Hurst: Chromosomes and Characters (1925) Pics

Hurst: The Conception of a Species (1927)

Hurst: The Mechanism of Heredity and Evolution (1927)

Harrison & Blackburn: Rose pollen (1927)

Hurst: Genetics of the Rose (1928)

Hurst: Differential Polyploidy (1928)

Hurst: Embryo-sac Formation (1931)

Hurst: Spontaneous Polyploids (1932)

Hurst: Polyploid Species with Pics (1932)

Gustafsson: Differential Polyploidy in Rubus (1939)

Blackhurst: Rubiginosa Hybrids (1948)

Darlington: Integrated Species Differences (1949)

Wylie: Why Caninae roses are different (1975)

Yokoya, et al. Nuclear DNA Amounts in Roses (2000)
In the Pimpinellifoliae, DNA amounts of tetraploids were disproportionately larger than those of diploids which suggests that they originated as hybrids with species of sections with larger DNA amounts. [CybeRose: i.e., differential polyploidy.]

Buck: Rosa laxa as a source of hardiness (1960)

Compare Buck's Laxa breeding with what Austin (1993) found while breeding from 'Conrad Ferdinand Meyer': "The third line we pursued was by way of the Rugosa hybrid 'Conrad Ferdinand Meyer.' At first we harbored no great hopes of success, for we feared that the resulting seedlings from a cross with this excessively vigorous hybrid would be altogether too gross in character. 'Conrad Ferdinand Meyer' was itself a cross between the very popular and beautiful Climbing Noisette Rose 'Gloire de Dijon,' and an unknown Rugosa hybrid. It also had one of the most powerful and delicious fragrances. As before, we crossed with some of our better English Rose in particular 'Chaucer,' and had one of those pieces of luck that sometimes turn up in rose breeding. Some of the seedlings from this cross were of typical rugosa appearance, while others bore absolutely no resemblance to a Rugosa Rose. It seemed that some of our hybrids had taken the genes only from the 'Gloire de Dijon' half of 'Conrad Ferdinand Meyer,' while others had inherited those from the Rugosa side. What we had in many instances were in effect hybrids of 'Gloire de Dijon'."


Macfarlane: Microscopic Analysis of Hybrids (1890)

Macfarlane: Flowering Period and Vigor of Hybrids (1891)

Macfarlane: Minute Structure of Plant Hybrids (1892)

Hurst: Partial Prepotance in Paphiopedilum (1900)

Comparison of Rosa sayi Schwein. with Carman's hybrid of 'Harison's Yellow' and R. rugosa. (1890)

Logan: Origin of the Logan berry (1902)

J. Hered.: Is the hybrid origin of the Loganberry a myth? (1916)

Anderson: Introgressive Hybridization (1949)
In the studies of introgression between these [Tradescantia] species it was not until after the artificial backcrosses had been made that we began to suspect the origin of the subaspera introgressants in T. canaliculata. These two species are strikingly different: T. canaliculata has a few long nodes, the uppermost of which are usually the longest. T. pilosa has many short nodes, and node length decreases progressively upwards. The introgressants of subaspera tend to have brilliant stems and leaves and a much higher node number than ordinary canaliculata. Though their nodes are somewhat shorter than in the latter, the extra number more than compensates, and the introgressants are frequently twice as tall as their unmongrelized sisters. These tallish, bright-stemmed canaliculata's superficially do not look at all like T. subaspera pilosa. It is only when careful studies are made of leaf shape, inflorescence characters, and pubescence that one finds that the whole complex in a greatly diluted form is tending to stay together in these peculiar variants.

Hurst: History of the Garden Roses (1941)

Gustafsson: Constitution of the Rosa canina complex (1944)

Crane & Darlington: Origin of New Forms in Rubus, I (1927)

Crane: Reproductive Versatility in Rubus. I Morphology and Inheritance

Crane & Thomas: Reproductive Versatility in Rubus. III Raspberry-Blackberry Hybrids (1949)

Malinowski: Differential pairing, suppression of characters (1927)

Anderson: Hybridization of the Habitat (1948)

Flory: Septets and Pollen in Rosa (1950)

Britton & Hull: Mitotic instability in Rubus (1957)

Riley: Wheat Septets (1958)

Ehrendorfer: Differentiation-hybridization cycles and polyploidy in Achillea (1959)

Sinskaya: Wide Hybridization in Alfalfa etc (1960)
If species which natural migration has brought from afar enter conditions which are very different from those of their earlier areas of distribution, the tendency of two species to mutual incompatibility may weaken, and then one can observe a mass production of natural interspecific hybrids between species of different chromosome levels in certain localities; under such conditions, not triploids, but fertile tetraploids are formed (we have studied an occurrence of this kind in Daghestan).

Hiesey: Cohesion of Traits (1965)

  1. The inheritance of characters distinguishing ecological races is mostly governed by multiple genes. Simple Mendelian segregation being rare;
  2. Systems of genetic coherence characterize ecologic races; when two races from different environments are crossed, the F2 tends to segregate with a higher frequency of parental types than would be predicted on the basis of free random recombination.
  3. Such coherence systems do not preclude the production of striking recombinations which provide rich potentials of genetic variation for further natural selection; genetic coherence is probably the basis for the differentiation of ecologic races, subspecies and species in higher plants.

Paterniani: Selection for Reproductive Isolation, Maize (1969.
Selection against hybridization between white flint maize and yellow sweet maize was conducted in field plots (Paterniani, 1969). After five generations of selection, the percentage of hybrids produced by white flint declined from 36% in the original population to 5%, and the percentage produced by yellow sweet declined from 47% to 3%. The strains diverged in flowering time, although they had similar phenologies to begin with. The selected white flint began to flower five days earlier than the original population and the selected yellow sweet two days later.
    Paterniani also found that a crossing barrier had arisen in the white flint selection line. In the original populations, 1:1 pollen mixtures of the two strains, produced close to 50% hybrids in both strains. This is to be expected with complete cross-compatibility. However, when white flint of the fourth selection generation received 1:1 pollen mixtures of various types, less than 30% of the progeny were hybrids (table 6.2). Yellow sweet pollen was at a competitive disadvantage to white flint pollen in white flint stigmas and styles. Oddly enough the selected yellow sweet line did not become more discriminating when used as the female parent.

Hiesey, Nobs: Coherence of Characters in Achillea (1970)

Heslop-Harrison: Gene expression in hybrids (1990)

Sax: Origin and Relationships of the Pomoideae (1931)

Challice: Phenolic compounds of the subfamily pomoideae (1973)