HOARY WILLOWHERB

Epilobium parviflorum

Willowherb Family [Onagraceae]

month8jul month8july month8aug month8sep month8sept

status
statusZnative
flower
flower8pink
flower
flower8lilac
inner
inner8cream
inner
inner8white
morph
morph8actino
petals
petalsZ4
stem
stem8round
sex
sexZbisexual

25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
Grows to 75cm high; less than half the height to which the similar, but larger flowered, Great Willowherb ascends.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The plant is hoary, with hairs sticking out, often angled ~45° downwards. The hairs are denser and cover the leaves and stems more comprehensively than those on Great Willowherb. The leaves do not clasp the stem, but have stalks, albeit sometimes very short stalks mostly hidden by the leaf itself.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
Leaf shape a little variable depending upon whether it is at the top, in the middle or at the bottom of the plant. They are tapered to a blunt point and rounded at their base.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The hairs are dense and with both glandular hairs (with a tiny bobble on the end) and plain hairs.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The seed pods are long, narrow with a square cross-section (but they are this shape on all Willowherbs).


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
A single flower will grow at the tip of each long narrow seed pod. Here most have already grown and dropped off; others are in various stages of decay before dropping off. Only one is fully open.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
And several nearby in various stages of opening. With Willowherbs, second to the leaves in identification importance, is the size of the flowers, the colour of their petals and the shape of the stigma.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
Unfortunately, this is the clearest photo of the sexual organs your Author could obtain from the only opened flower. On Hoary Willowherb (and several others) the stigma is 4-lobed (rather than club-shaped as in some other Willowherbs). The 4-lobed stigmas on Hoary Willowherb are said to differ in shape of other Willowherbs with 4 stigma lobes: they are said to be held nearly vertically (rather than horizontally). However - from this photos, the pollen is getting in the way of most or all of the 4 lobes of the stigma! Most of the white objects that can be seen are the ten T-bar anthers and their creamy pollen cases.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
Luckily, your Author thought it wise to measure the size of the petals. These are about 7mm long and within the specified 5 to 9mm for Hoary Willowherb. And here the 4 white stigma in the centre are clearly not horizontally splayed out, but nearly vertical, touching each other. So this too confirms the Hoary Willowherb identification.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The seed pods have a mixture of glandular and non-glandular hairs.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The glandular hairs have a blob at their summit.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
A branch stem with both glandular and non-glandular hairs.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The hoary stems; hairs dense and here mostly angled downwards at a 45° angle.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
A lower leaf, one with less hairs.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The underside of the lower leaf.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
There are 4 sepals.


25th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
At ground zero. There are a multitude of stems growing here.


30th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
There's a good reason why all these are all one way up: there are one or two deep grooves on the reverse, making that side the more stable to come to rest at. And the seeds are tiny! Less than 1mm long and virtually manually uncontrollable on a flat sheet of paper. The spacing of the black lines on the right is 1mm - it is a ruler! But on this side of the seeds you can also see the minute pimples on this surface which are mainly absent from the other (grooved) side. The seeds taper to a blunt tip ate one end, and are slightly curved. The seeds are about 0.85mm long and 0.4mm wide. But in Hoary Willowherb, the size of the seeds is no guide to identification; several other Willowherbs have much the same size seeds. The size and shape of seeds is only useful to help identify Marsh, Chickweed, Broad-leaved, American and New-zealand Willowherbs.


30th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
The miniscule seeds attached to their white parachute hairs. The long pods have been manually peeled open like an extremely long banana, somewhat disturbing the neat stacking of the seeds and their parachutes within the pod. The pods are very numerous: their are seeds tightly packed in each of the 4 sides of the long pods.Because these seeds had no chance to flip over on to their grooved sides, you can see the two parallel U-shaped grooves on some of them. The others are displaying their un-grooved pimpled sides.


30th July 2019, a garden, Walkden, Gtr M/cr. Photo: © RWD
A blow-up of the grooves and the micrometer-thick parachute hairs. At a guestimate, the hairs are 10µm thick (and that guess might be limited by the size of the cameras pixels and lens resolution).


Hybridizes with :

  • Broad-Leaved Willowherb (Epilobium montanum) to produce Epilobium × limosum which is one of the commonest hybrids of Willowherb.
  • Great Willowherb (Epilobium hirsutum) to produce Epilobium × subhirsutum which has been found scattered in Guernsey and also from Northern Britain to Central Scotland
  • Spear-leaved Willowherb (Epilobium lanceolatum) to produce Epilobium × aschersonianum which was found in South Devon and East Kent several years ago.
  • Square-stalked Willowherb (Epilobium tetragonium) to produce Epilobium × palatinum which has been found scattered in South Britain and north to East Norfolk as well as Guernsey.
  • Short-fruited Willowherb (Epilobium obscvurum) to produce Epilobium × dacicum which is scattered in most of the Britain Isles.
  • Pale Willowherb (Epilobium roseum) to produce Epilobium × persicinum which is scattered in England and Monmouthshire.
  • American Willowherb (Epilobium ciliatum) to produce Epilobium × floridulum which is scattered over most of Britain from Northern Britain to Central Scotland.
  • Marsh Willowherb (Epilobium palustre) to produce Epilobium × rivulare which is mostly found scattered in Western Britain, but also elsewhere and Ireland.
  • New-Zealand Willowherb (Epilobium brunnescens) to produce Epilobium × chateri which was found in East Cornwall in 2002 but not elsewhere.

Many similarities to : Great Willowherb (Epilobium hirsutum) but that is much taller at up to 1.8m, and also usually has larger flowers with petals between 10 and 18mm long, but can occasionally be as short as 6mm or as long as 18mm. This plant also has a mixture of glandular hairs and normal hairs. unlike Hoary Willowherb, the 4 styles in the flowers splay out sideways rather than point upwards.

Hoary Willowherb likes much the same habitat as does the very similar Great Willowherb, namely in wet or damp places almost anywhere. With a clay soil which blocks the progress of water, the above garden seems to suit admirably during a wettish July.


  Epilobium parviflorum  ⇐ Global Aspect ⇒ Onagraceae  

Distribution
 family8Willowherb family8Onagraceae
 BSBI maps
genus8Epilobium
Epilobium
(Willowherbs)

HOARY WILLOWHERB

Epilobium parviflorum

Willowherb Family [Onagraceae]