Comesperma flavum

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Comesperma flavum

This small plant like others in its genus is highly opportunistic to local summer rainfall by rapidly producing additional flowers. They begin normal flowering during late spring when the days are warm and there is still plenty of moisture in the soil, after which they produce their seed, but if additional moisture becomes available, they quickly develop more flowers just above the earlier produced seed capsules.

Due to this repetitive floral development, the bright cream/yellow flowers can usually be seen throughout late spring, summer and the autumn period; all that is required is warmth and moisture. Comesperma flavum is mainly distributed in near coastal environments from Perth to Albany and again around Esperance. Drier conditions (as is the case around Esperance) will influence the growth of the plants, of which locally they are usually less than ½ metre (20”) in height, but in more sheltered environments to the west, they can reach 11/2 metres (5’).

Locally, the preferred habitat of Comesperma flavum is non-calcareous sandy soil on the outer edge of slow moving seepage zones, especially where they enter swamps or flood plains. These areas provide the necessary moisture during spring and early summer when it first comes into flower, plus the habitat remains moist, or is replenished after summer rainfall for the second flowering period.

The bright autumn flowers of Comesperma flavum are most welcome, as there are few plants in bloom at this time, other than the odd eucalypt and a few Proteaceae.

Comesperma is part of Polygalaceae, the Milkwort family.

Comesperma spinosum - Spiny Milkwort

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Comesperma spinosum - Spiny Milkwort

A common and widespread shrub, although preferring near coastal mallee regions, where favouring the heavier loams over limestone, clay or gravel. It looks prickly and indeed is, especially when trying to collect a specimen that usually results in spilt blood, however there is rarely the need to touch them as they invariably grow into a compact shrub, with a fine compliment of bright purple/blue flowers.

Comesperma spinosum seldom grows more than ½ metre (20”) in height, unless jammed in amongst taller vegetation to force it up to around twice that size. The foliage consists of minute scales scattered on multi-branching stems, all of which end in a short stiff spine, and due to this prickly arrangement the Spiny Milkwort is unlikely to be confused with other Comesperma species.

The flowers are about 1 cm (3/8”) wide and commonly bloom from September to December, although odd flowers are often encountered at other times, especially after good summer rain. The capsule is of similar size to that of the bud (except heart shaped) and is produced soon after the flower has finished. Interestingly, the inner two seeds differ from most other Comesperma species by not having a tuft of hair at their base (coma), from which the genus (Comesperma) gets its name. Unfortunately, I don’t have a photo of the seed, but shall add one when obtained.

The distribution of the Spiny Milkwort is from the Israelite Bay/Mt Ragged region (East of Esperance) to the Stirling Range (NE of Albany), it then extends patchily inland to NE of Geraldton and then to the Southern Cross district (SW of Kalgoorlie). Comesperma spinosum is another WA endemic (as are many Comesperma spp.), so is not found elsewhere.

The Comesperma genus is part of the Polygalaceae family.

Comesperma confertum - Milkwort

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Comesperma confertum - Milkwort

The genus name of Comesperma refers to the tuft of hairs (coma) that are attached to the seed (sperma), which just so happens are similar in appearance to the shape of a comma (punctuation mark). These are attractive long flowering plants and bear some resemblance to pea-flowers by having large standard-like petals and a central keel petal, but they are not related.

An important feature with plants in this genus is the sepal arrangement (the lobes on the outside of the flower, which can be seen at the base of the coloured petals). Basically, if they are all free (unattached) from each other, although some may overlap, then these belong to one group, whilst another group has two of the sepals joined for most of their length. With Comesperma confertum the sepals are all free, which is important as it separates this species from another, although there are other differences.

The other similar species is Comesperma virgatum, which is often found growing in the same area as C. confertum, but besides the different sepal arrangement the leaves also differ, although appearing much the same from casual observation. With C. confertum the leaves are quite soft and the edges recurved, whilst the leaves of C. virgatum are thicker, flat and with a prominent vein below (the leaf keel).

Comesperma confertum grows to around a metre (3’) in height and unless tip pruned by browsing animals, is very upright and sparsely branched, whilst those that have, develop into a multi-branched shrub although still quite open. It is generally found in near-coastal environments from Kalbarri to Cape Arid, primarily in non-calcareous sandy soils, which can also overlie limestone or granite.

The flowers come in various shades of pink and even light purple, which are produced prolifically from September to December as the top of the flowering raceme continually grows, thereby producing more flowers providing there is also regular rainfall over the same period.

Comesperma calymega - Blue-spike Milkwort

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Comesperma calymega - Blue-spike Milkwort

A total of 32 species (one undescribed) in the Comesperma genus are found throughout Australia, of which 21 occur in Western Australia. They comprise a mixture of climbers, small shrubs and perennial herbs, the latter dying back to the rootstock during hot dry conditions, to grow again after good rainfall the following winter/early spring period. Comesperma calymega is one of the perennial herbs

The Blue-spike Milkwort occurs across southern Australia including SA, Victoria and Tasmania, whilst in WA it is found SW of a line between Cape Arid (100 km or 60 miles E of Esperance) and Kalbarri (500 km or 310 miles N of Perth). It usually grows to around 30 cm (12”) in height, although it can get a little taller. It has ovate leaves at the base and narrower ones further up the stem (in drier conditions the lower leaves may also be quite narrow).

This species produces an elongated raceme of brightly coloured flowers, which mature from the raceme base upwards. It is often the case that the flowers will bloom and produce seed capsules, but after additional rainfall will go on to produce another crop of flowers above the earlier ones (now gone to seed). So these plants depending on weather conditions, can flower over a number of months.

Generally, Comesperma species appreciate periodic bushfires and/or soil disturbance to reduce plant competition and enhance seed germination; even slashed bush tracks or firebreaks provide ideal growing conditions. Comesperma calymega favours deep non-calcareous sandy soils, commonly associated with heath plant communities. However it is surprisingly adaptable and can also be found on rocky outcrops and gravel soils, providing the habitat is well-drained but with some moisture holding ability.

The sepals (enclosing the flower) are not attached to each other (free) and the closed petals only just protrude above them (see close-up of light purple flower above). Also in the same photograph; besides the flower’s two large petals, the smaller central (keel) one is clearly three lobed. These flowers are mostly blue, but occasionally light purple forms are also encountered. Flowering depending on weather conditions occurs between August and January.

Locally there is only one other Comesperma species that could be confused with C. calymega, and that is Comesperma lanceolatum, but this is a much rarer species only found along the southcoast in deep non-calcareous sand on or near the summit of large sand hills. The most obvious difference between them is the flowers of this species are restricted to a compact terminal raceme and not an elongated one.

The genus name of Comesperma refers to most species having long hairs attached to the seed, giving them the appearance of a comma once released from the capsule. The hairs are held (as the seed matures) in the elongated capsule base (below the seed). Comesperma belongs to the Polygalaceae family.