Family: Willowherb [Onangraceae]


Chamerion

Circaea

Clarkia

Epilobium

Fuchsia

Ludwigia

Oenothera

Zauschneria



[EPILOBIUM] Willowherbs

 

EPILOBIUM HYBRID CHART (shrunk)
Hybrid Chart: WILLOWHERB (larger)

Missing from the above chart are two triple hybrids, namely
Epilobium montanum × obscurum × parviflorum
Epilobium montanum × parviflorum × roseum
which are over-lapped on the chart by other normal hybrids.

Epilobium SPECIES LACKING HYBRIDS
(Epilobium komarovianum) Bronzy Willowherb
(Epilobium lactiflora)

Most of the Willowherbs hybridize freely with one another. The above is a chart of all the known hybrids of the Willowherbs with other Willowherbs. Note how Bronzy Willowherb has no known hybrids, and that Rosebay Willowherb does not appear in the chart, for it has no hybrids either and although it is a Willowherb, it is not an Epilobium. Rockery Willowherb has only one hybrid, that with Broad-Leaved Willowherb, whereas Broad-Leaved Willowherb has many hybrids. Together, Short-Fruited and Broad-Leaved Willowherbs have the most known hybrids, totalling 11 (out of a possible 12). The empty dark-brown squares show that there is plenty of opportunity for much more promiscuity between willowherbs.

N.B. Due to the symmetrical nature of the chart, being folded about the black diagonal, each hybrid appears twice.

All Willowgerbs have long seed pods, which when ripe split open like a banana to reveal hundreds of seeds with long feathery plumes, ready to be borne on the wind to set seed in far-off places. a single plant can produce up to 20,000 seeds. Little wonder then that once a willowherb has a foot-hold in a garden, it is almost impossible to eradicate, for the plants grow faster than gardeners on a fortnights holiday can control. The smaller varieties have set seed before the gardener is even aware of their presence.

The characteristics by which Willowherbs can be differentiated from one another concern the shape of the stigma (club-shaped or '+'-shaped) the type of hairs, the branching, if any, the usual colour of the flower, and its size and shape. Also the shape of the leaves. The shape of the stem (round or square) is also an important ID feature in Willowherbs (although seemingly not used in some keys). The presence or absence of either runners above the soil surface or rhizomes below it are also indicative features.

All willowherbs have long fruits which are square in cross-section and contain rows of seeds with long overlapping white hairs, the pappus, to aid its dispersal in the wind. When ripe the fruits split open along the four edges like an un-zipped banana revealing the seeds with pappii. After drying they are able to flee on a slight breeze.

Willowherbs hybridise freely with one another species, their hybrids commonly occurring where two (or more) compatible Willowherbs occur in the vicinity. They are usually recognised by their larger and more branched nature, their longer flowering season, by their unusually large or unusually small flowers and by the darker coloured tips of petals. Their fruits are either partially or entirely abortive, but some seeds within are fertile, able to back-cross or form a triple (or even a quadruple) hybrid with other compatible species of Willowherbs.

Most hybrids are intermediate in character between the parents., most notably in the shape of the stigma (club or cross) and the type of hairs.



[CHAMERION] Rosebay Willowherb

Rosebay Willowherb. (Chamerion angustifolium) Photo: © RWD



[EPILOBIUM] Willowherbs

Great Willowherb. (Epilobium hirsutum) Photo: © RWD



[EPILOBIUM] Willowherbs

New Zealand Willowherb (Epilobium brunnescens) Photo: © RWD

American Willowherb (Epilobium ciliatum) Photo: © RWD

BroadLeaved Willowherb (Epilobium montanum) Photo: © RWD



[OENOTHERA] Evening-primrose

 

[Oenothera]
EVENING-PRIMROSE HYBRID CHART
[Oenothera]
EVENING PRIMROSE
HYBRIDS
BSBI MAPS
Common
Evening-primrose

(biennis)
Small-flowered
Evening-primrose

(cambrica)
Large-flowered
Evening-primrose

(glazioviana)
Large-flowered
Evening-primrose

(glazioviana)
Oenothera
×
fallax
Oenothera
×
britannica
Small-flowered
Evening-primrose

(cambrica)
biennis
×
cambrica
Oenothera
×
britannica
Common
Evening-primrose

(biennis)
biennis
×
cambrica
Oenothera
×
fallax

In addition, and not shown on the above chart, there is a triple hybrid; a hybrid between all three Evening-Primroses shown above, Oenothera biennis x cambrica x glazioviana.

The Sefton Coast is renown for the hybrid swarm between Common Evening-primrose and Large-flowered Evening-primrose, the hybrid is commonly called Intermediate Evening-primrose and shown on the chart as Oenothera × fallax. Reciprocal crosses also occur between O. glazioviana and O. cambrica.

The hybrid between O. fallax and a female O. glazioviana is known as O. × brittanica (and is not shown on the chart).

Oenothera SPECIES LACKING HYBRIDS
(Oenothera agg.) Evening Primrose agg.
(Oenothera grandiflora)
(Oenothera laciniata)
(Oenothera missouriensis) Missouri Evening Primrose
(Oenothera oakesiana)
(Oenothera parviflora)
(Oenothera renneri)
(Oenothera rosea)
(Oenothera rubricaulis)
(Oenothera salicifolia)
(Oenothera stricta) Fragrant Evening-primrose
(Oenothera tetraptera)



[FUCHSIA] Fuchsias

Hedge Fuchsia (Fuchsia magellanica) Photo: © RWD

Family: Willowherb [Onangraceae]

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