Hybrid Origins?

Tradescantia (Andersoniana Group) ‘Innocence’

I am sure this will be resolved over the coming weeks and months, but at the moment I am very confused about the origins and status of the Andersoniana Group hybrids. It seems pretty clear from all the research I have read that the parentage of most of the original hybrids were Tradescantia virginiana, Tradescantia ohiensis and Tradescantia subaspera. However, it is also true that Anderson himself found very few hybrids in the wild because although these three species share overlapping ranges, they enjoy differing habitats, therefore rarely coming into contact.

So, this led Anderson to speculate that it was only when two or more of these species were grown together in close proximity that hybrids began to appear through cross pollination. Tradescantia was certainly one of the first plants to be introduced into Europe from North America by John Tradescant the Younger in 1629, some 120 years before Carl Linnaeus even named the plant Tradescantia virginiana in Species Plantarum in 1753, certainly long enough for multiple hybrids to appear in domestic and botanic gardens in the UK and on the continent of Europe. However, Anderson then went further and showed through gene and cell research that these hybrids also crossed back with one or more of their parents creating ‘interspecific hybrids’.

Over the last 200 years, hybrids worthy of cultivation have been selected, propagated vegetatively, and, until recently, were known by the name Tradescantia × andersoniana. Further deliberate crossing and back-crossing has subsequently produced huge variations in flower colour and size, leaf colour and form, height, vigour and flowering period. Of course, naturally occurring hybrids are still being discovered and selected, and I think it is probably true to say that what we now call Tradescantia Andersoniana Group is a mixture of both.

Tradescantia virginiana ‘Brevicaulis’

I am indebted to Jorge of blog.primrose.co.uk
for the following detail which explains the origins and
differences between Species, Variety and Cultivar.

What is a species? One definition states a species is a group of
similar individuals which can
reproduce successfully with each other
while at the same time being reproductively isolated from other similar
species. This definition leaves it up to scientists to decide when a group of
individuals is distinct with some placing greater weight on genetics, others
more obvious characteristics such as their morphology.

When a group of individuals becomes geographically isolated, it will
begin to develop unique traits, making it distinct from the rest of the
species. These distinct groups are known as varieties. Over time, they may
become so different from the parent group that they are unable to breed,
leading to the creation of a new species. Often, however, a variety comes into
contact with its
parent group, resulting in an influx of genes that
erodes their distinct features, reintegrating it into the greater species
group.

Varieties are true to type as their seeds produce offspring with the
same unique characteristics of the parent plant. Cultivars are distinct from
varieties in that they do not occur naturally in the wild. Cultivars are selected
by humans for specific characteristics and are propagated through vegetative
cuttings i.e. cloning. Propagation by seed will often lead to something
different from the parent plant and as such they aren’t true to type”.

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