Pimelia – a Beginner’s Guide

Welcome to my vegetation blog!   I plan to cover all sorts of different bits and pieces that might be of interest to anyone who wants to know more detail about the bush in Victoria, and will add to the blog with a new article every week or so.......

This initial post is the first of what will be a short series on the genus Pimelia and will give some information about the following species of Pimelia:

Pimelia glauca Smooth Rice-flower
Pimelia humilis Common Rice-flower
Pimelia curviflora Curved Rice-flower

Pimelia humilis - note the large floral bracts.

When you are looking at these cute cute plants, there is one thing you need to have your head around, and that is floral bracts.   Most pimelias are distinctive for the presence of these floral bracts, and sometimes you need to look closely at the floral bracts to see whether you are indeed looking at a pimelia, or to decide which one it is.  

You can Google floral bracts, or you can check the glossary of any good flora, but basically they are leaf-like structures that subtend (hold on to the stem right beneath) the inflorescence (assume if you’re reading this you know what an inflorescence is, but just in case, it means the whole group of flowers found together in each flower cluster).   The bracts are right up there under the inflorescence and a close look will reveal that they are different from the leaves on the stem.   In the case of Pimelia there are often four of them, but sometimes a few more, depending on the species.    The bracts sometimes hold some important diagnostic features for the species – for example when sorting out pimelias glauca and humilis.

The other things about pimelias in general is that they: 

• are always a shrub whether very short (up to half a meter) and small, or more substantial
• always have four flower petals
• are always white, cream or yellow
• usually have leaves arranged in opposite pairs on the stem(some exceptions).

One of the best things about pimelias is that there is a species of this plant for almost every habitat here in Victoria.   So whether you are down at the beach or up in the mountains, you can find one.   

I especially love plants that do this.     I love that they have sorted themselves out to make sure they got a spot anywhere they found themselves, back in the days when they were evolving.

And they are so pretty – if you are reading this post for info for planting up a local native plant garden, read on!   Yes you should include a Pimelia, but make sure it will fit the habitat you’re giving it.

So here we go, and I’ll start with the only two pimelias that you are likely to have trouble differentiating.

Pimelia glauca   (Smooth Rice Flower)

Pimelia glauca at Sunbury, Victo

It took me some time to realise that I was confusing Pimelia glauca with Pimelia humilis, and probably misnaming the former as the latter.    This was probably because they both inhabit grasslands, and it was grasslands, most likely, where I first became aware of Pimelia.   And it was also because to the unfamiliar eye they seem very similar.

Having realized this confusion, I checked it out, and the differences are:

Habitat
Pimelia glauca sticks to open habitats, particularly grasslands.   (I understand it is also to be found on sand-dunes on the coast).   I've only ever seen it in very open Basalt Plains grasslands on the northern fringes of Melbourne.   Even within open patches of forests and woodlands, if there is a pimelia, it will be humilis, never, it seems, glauca.
Flowering time
P glauca has a big flowering flush for a short time in October and then it is more or less all over, with occasional flowers, if you're lucky, through til late December.
Size
P glauca is small, up to around half a meter, but very showy, very broad with lots of branches.   Also it tends to occur in groups, as do many of our native shrubs.
Presence
P glauca has lots of it.   Multi-branched, lots of flowers, lots of plants having a party together.  You really notice it when its in flower.  Presence is the spotting characteristic that tells you as you walk up to it, that it’s probably going to be glauca and not humilis.    Pimelia glauca is solid, it is lots, it is in your face, it is quite a striking plant, or usually, a big, showy group of plants.
Also
More technically for a closer look:   stems are not hairy, are often stick-like (woody) brown or yellowish; hairs occur on only the inner two of the four floral bracts.


Pimelia Humilis (Common Rice-flower)
Habitat  More or less anywhere!   (that's why its called "Common")   Forests, heaths, woodlands......you will see it all over the place.
Flowering time
Unlike its cousin P glauca, Pimelia humilis is happy to keep on flowering through the warmer months and longer days, starting in September, and going through until the end of January.
Size
Small again - up to 50 cm tall, but usually shorter, very much down among the ground flora.
Presence

Pimelia humilis is just that – humble.    You might not even notice it at first.    In its humility it seems to choose company with a lot more pizzaz, like bright gold everlastings and vivid blue pincushions, massed Bulbines and chocolate lilies.  The occasional Pimelia humilis nestled modestly in amongst the grass is easy to overlook.   So glauca is a show-off and humilis is dainty.  Modest. Humble.    Usually.   I know one site where the Pimelia humilis stands up tall and sassy and bright white and that is a forest site rather than a woodland – where everything is taller and here little humilis decided it was be bold or be perished.

Pimelia curviflora (Curved Rice Flower).

Closer view of Pimelia curviflora

Pimelia curviflora has a range of habitats along the grassy understorey spectrum.  It finds a spot for itself, and therefore a function (more on function in a later post) in grasslands and in grassy woodlands and open, grassy and dry forests (a major forest type here in Victoria).    

P. curviflora is slightly built

P curviflora is another very small pimelia - growing up to about 30 cm.   And its build is slight, as shown in the bottom photo.  Easy to walk past without noticing, it is another in the dainty category.   For a plant that is so easy to miss, it's distinctive amongst pimelias in that it sometimes lacks the usual floral bracts, its leaves are alternate, not opposite like those of most of its cousins, and its flower petals are shaped very differently from those of many pimelias.

They seem to occur in sparse groups with perhaps two or three other plants close by. 

There seems to be some problem with naming sub-species.   Flora of Melbourne originally had Pimelia curviflora var sericea, but later editions have in the appendix an entry for Pimelia curviflora and a comment that the National Herbarium recognises no varieties or subspecies.

More Pimelias in a future post.