The Nature of Bladderworts - (Fairies Aprons)

Several days ago, Duncan commented on my previous post about "Fairies Aprons". Duncan pointed out that in Gippsland, the country was drying out, and the once common Bladderworts were disappearing. He wrote:

• "You captured the colour of the Utricularia beautifully, a gorgeous little plant. The swamps around here that used to hold it have been dry for quite a few years now, so we may have lost it. However Gouldiae and I were pleased to find it flowering in a sphagnum moss swamp in the high country last season."

Large "Fairies Aprons" - Utricularia dichotoma

Very generous comments by Duncan, thanks. Unfortunately, I cannot make it rain in Gippsland, guys. I wish.....

Where I saw these plants is on a flat sandstone plateau, with poor drainage, and as we have had the occasional "top-up" of rain recently, the low-lying areas are water logged. That is where these plants love to grow - preferably in shallow water. In Robertson, with deep, friable soil, the country does not feel wet. By contrast, just 5 Km away, on the flat sandstone plateau, if the rock sheet under the shallow soil is more-or-less continuous (as it generally is), then although the sandy soil is not good at holding water, the rock layer just below traps the water very effectively indeed. Hence, pools of water in shallow soil areas, lying on the flat sandstone base are common.

As a gardener, in Canberra, I remember trying to understand the instructions for growing Christmas Bells - you needed "moist, well drained, soil". As someone living on deep loamy soil (at the time), I wondered how on earth could one have those seemingly contradictory soil conditions? Simple answer, move to where there is a flat sandstone plateau, in a high rainfall area.

That's what the Carrington and Gerringong Falls areas, on the Budderoo Plateau and the Barren Grounds does better than just about anywhere else I know of. These same areas grows Fairies Aprons well, in addition to the Christmas Bells I mentioned - (but they are not yet in flower).

Tiny flowers of the "Small Bladderwort" - Utricularia lateriflora

This species is a genuinely tiny plant - growing only a mere 6 cm tall, (or less) - shorter than my finger. They are growing out on the Barren Grounds, beside a track, in a shallow pool of clear water.

Botanical Illustration from PlantNET
it clearly shows the "spur" underneath the main petal (lower left image)

The flowers are a softer lilac colour than the other species, and much, much smaller. In fact, if I had not been looking up the books a few days beforehand, I would not have recognised these plants as "Fairies Aprons".

There is a prominent structure, referred to as a "spur" underneath the main, lower, "lip-like" petal. After much searching I have finally found a reference to the biological or reproductive function of the "spur" underneath the main petal. Apparently the spur is a nectary, and so it is the attractive part of the flower for a large pollinator, like a Bee. The Bee lands on the front of the flower, the petal, and the weight of the Bee pulls down the petal, opening up the top of the "spur" to the proboscis of the Bee. It also exposes the stigma of the plant to be pollinated.
Just about everything about "Bladderworts" is unusual. According to the technical botanists, they do not have true roots, or even true leaves. Instead they are described as having "stolons" - which act as "leaves", and also as "roots" and in addition these stolons also produce "Bladders" which act like traps. These are touch-sensitive devices which can open their "doors" suddenly (like the mouth of a fish) to suck in water, and then any minute animals which might have been caught are then absorbed, chemically. F.E. Lloyd, Emeritus Professor of Botany at McGill University literally "wrote the book" on Carnivorous Plants, in 1942.

Front view of Utricularia laterifolia
This is approx 6 times life size. It is a tiny flower.

Utricularias, ("Bladderworts" or "Fairies Aprons") are carnivorous plants. As such they are beloved of collectors of carnivorous plants, from Sundews, to Venus Fly Traps. Problem is, unlike Sundews, you cannot see them "eating" their prey, for their method of trapping minute prey is hidden underground, or underwater. They produce "Bladders" on their underground (or underwater) stolons. This is very well illustrated on this link. I will never think badly of "trainspotters" again - these Carnivorous Plant enthusiasts take the cake - for obsessiveness.

But having said that, clearly Duncan and I both like Utricularias.

Biographical notes: I vividly remember, as a child, going on plant outings with my family in the company of an old, but venerable lady - a famous plant expert in Melbourne, in those days. She was Miss Winifred Waddell. Miss Waddell was a bit of a character, and had very strong views against the Mr Arthur Swaby, and the other founders of the Society for Growing Australian Plants as "murderers" (of native plants - I hasten to add). This was because of the SGAP policy of preserving native plant species, by growing them in gardens. Miss Waddell was a pure conservationist (indeed a "preservationist") - fighting to protect the last vestiges of habitat of rare plants. She was very keen on establishing "roadside reserves", and would she would endlessly lobby the Country Roads Authority to establish such reserves. I recall going out on the roads near Dandenong. Having revisited these areas last year, I doubt that many, if any, of these tiny roadside reserves have survived the crazy spread of suburbia in eastern Melbourne.

My mother used tell the story of receiving a phone call from Miss Waddell one evening, asking for my father. Mum happily told her that Dad was off at the inaugural meeting of Mr Swabey's group. Miss Waddell just said: "Humph - those Murderers !!!" and hung up.

Ah, the Politics of Conservation were alive and well, over 50 years ago.

But what I remember most vividly is being with this lady when we would find tiny Sundews and Fairies Aprons - the "little darlings". As I was an 8 year old, with sharp eyes, I was good at finding these things. Happy memories for me - no wonder I love these plants - some 50 years later.

Miss Waddell's entry in the "Women in Australian Science" "Bright Sparcs" website is here.