Isopogon scabriusculus subsp. pubifloris – Cone-flower

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Isopogon scabriusculus subsp. pubifloris – Cone-flower

This species is not common in the Esperance region and is only found in mallee heathland to the northwest; the above occurring in a sandy loam over gravel around 130 km from Esperance. It is however, much more abundant further west, extending to Lake King, Hyden, Southern Cross and the Frank Hann National Park.

There are two other subspecies, neither known to occur in the Esperance region, but they do overlap with this subspecies elsewhere. This subspecies is easily separated from the others by having hairs on the outside of the flowers, whereas the others (subsp. stenophyllus and subsp. scabriusculus) are without external floral hairs and differ from each other by the shape of their leaves.

Locally, Isopogon scabriusculus subsp. pubifloris is an open upright shrub to 1.2 metres (4’) in height, with minutely scabrous (fine sandpaper-like surface) terete leaves (rounded in cross-section) to 13 cm (5”) in length. The pink, purple and red flowers are mostly grouped at the summit of the previous years growth, to later produce a globular cone (over 1 cm or ½” diameter), which disintegrates after fire to release the seed.

Flowering is recorded from August to December, although this would depend on seasonal rainfall with the above starting late September to probably finish by November.

Isopogon is another ornamental genus of the large and diverse Proteaceae family. Plants within this genus are common known as Cone-flowers or Drumsticks.

Elkhorn Coneflower - Isopogon alcicornis

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Elkhorn Coneflower - Isopogon alcicornis

Isopogon alcicornis is an exotic looking plant with long leaves; many divided to resemble an Elkhorn Fern. Unfortunately it is an endangered species with a Priority Three Conservation Status, which means it is known from several locations (around Esperance to the Cape Arid region, 110 km or 70 miles to the east) and although not currently endangered, is in urgent need of further study. I know it from 40 km (25 miles) NE of Esperance, where odd plants grow in sand over gravel on a roadside reserve, in association with shrubby Proteaceae heath; adjacent farmland clearance would be the main reason for its local decline. A larger colony exists in the same district where saline water drains along a small flood plain into a saltlake, where surrounding and associated vegetation are Acacia, Melaleuca, Stipa (spear-grass), scattered salt tolerant shrubs and the occasional mallee eucalypt. Whilst not growing in the salt-laden zone, the Elkhorn Coneflower is distributed to the side of the drainage flow, growing in a fine sand/clay over clay.

The almost vertical lime green leaves, grow to 45 cm (1’6”) in length, and the yellow/gold flowers (5 cm or 2” diameter) nestle at their base, requiring them to be parted to obtain a clear view. The WA Herbarium record the flowers as being yellow, white or pink, which may represent local forms or just floral development stages. Also they have the flowering period from October to February, but these times would be related to variable climate conditions, as cooler/wetter conditions can considerably delay or extend flowering. The Elkhorn Coneflowers I observed began to bloom in September and finished in November, but this has been a hot/dry year.

Apparently, Isopogon alcicornis has a lignotuber, which means it will regrow rapidly from the tuberous rootsystem after bushfires. To me this indicates it would benefit from more regular fires to reduce competition from other plants that initially grow more slowly after seed germination, also the fresh regrowth free of old leaves, would permit pollinators easier access to flowers.

Isopogon sp. - Fitzgerald River

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Isopogon sp. - Fitzgerald River

An interesting shrub to around 2 metres (6') in height, with pink flowers and various colored foliage of cream/green, green and pink/red. When first seen, I was sure I had at last come across Isopogon attenuatus (previously recorded for the Esperance district), which is similar to the more common Isopogon polycephalus Proteaceae - Isopogon - Clustered the Clustered Coneflower, but with the main difference being several flower heads in terminal clusters as against Isopogon attenuatus having only the one. However on checking the FloraBase (Perth Herbarium) website, they have redistributed Isopogon attenuatus much further west to the Albany region, now making it 300-400 km (220 miles) out of its range.

This Isopogon keys quite well to I. attenuatus, except for the height (taller), plus the foliage and flower color (pink as against yellow), which are often variable features. However combined with being so far from its now distribution, it must be questioned. There were a number of plants scattered along either side of a roadside reserve, where the soil was laterite and probably quite boggy after rain. Surrounding vegetation was shrubby in a low open mallee woodland. Location was Mills Road, approximately 85 km (52 miles) NW of Esperance.

This Isopogon was just beginning to flower in late May and will probably (along with later flowering plants) continue for another 2-3 months. However this year there has been regular rainfall (although not heavy), therefore with drier conditions the flowering period could easily be delayed.

Update 3/08/09

This species is officially known as Isopogon sp. - Fitzgerald River, which was gleamed from the Perth Harbarium FloraBase website. After another visit to the region, it was encountered in a number of gravel soil sites further west, so would be well recorded.

Update June 2013
Three photographs added, one removed.  This species is very common in the Lake Tay region 140 km (85 miles) NE of Esperance.

Rose Coneflower - Isopogon formosus subsp. formosus

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Rose Coneflower - Isopogon formosus subsp. formosus

The botanical name of Isopogon formosus, refers to this plants beauty that I fully concur. The 5 cm (2") diameter terminal flowers are a rich magenta and perched on top of neatly symmetrical and compact divided foliage, thereby presenting a most pleasing spectacle. Fortunately the foliage is prickly, so not suitable for the cut-flower trade, otherwise its numbers in the bush might have been compromised by now.

There are two subspecies, but the other one, 'subsp. dasylepis' is rare and only found in the far southwest corner of WA, so well outside the Esperance region. The local subsp. formosus, is recorded growing to 2 metres (over 6') in height, but most plants in this area are closer to 1 metre (around 3') and can be found in low-lying sandy areas, particularly when over-lying heavier soils; on flood plains; on granite outcrops where there are pockets of laterite or eroded broken rock, plus on sandy rises where seepage drains from one ephemeral swamp to another.

Not sure of the pollinator for these plants, but with the long narrow floral tube, something with a long proboscis, maybe one of the larger moths. Recorded flowering from July to December, but in the Esperance region, August to October would be the main period, although variation in seasonal rainfall could extend this either way.

Update 21/03/2010
Several photographs exchanged.

Clustered Coneflower - Isopogon polycephalus

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Clustered Coneflower - Isopogon polycephalus

A common shrub of around a metre (3'), although in sheltered locations it can reach twice that height. Very adaptable regarding habitat, but the greatest number of plants can be found in deep sandy soil in flat low-lying areas surrounding ephemeral swamps or where there is subsurface moisture, however they will venture to higher and lower altitudes, in both drier and wetter habitats. Also found in sand overlying laterite and granite, so a very widespread heathland species.

You could be forgiven for thinking that this plant never flowers as you need to look very closely for the tiny flowers, which vary from 2-4 mm (around 1/8") in length and blend into the similar colored, compact hairy bracts of the flower head. The flower heads are usually around 1 cm (3/8") diameter and mostly in a terminal three-headed cluster (occasionally singularly in young plants, or in the upper leaf axils of more mature ones).

Although the flowers are small and designed for insect pollination, they are quite attractive in their setting. Many people think Western Australia is only adorned with big, bright and spectacular flowers, but there are less eye-catching plants that are also well worth a second look, as they successfully compete with the more spectacular ones for the attention of pollinators and indicate the huge diversity of species growing side by side in the highly floristic regions of Western Australia.

Flowering occurs anytime from August to January or even later if there are summer rains. The flowering heads are commonly encountered in all stages of growth, so the blooms can usually be found with little effort. The leaves, commonly between 3-10 cm (1"-4") in length, are a yellowish green and stand upright from sturdy stems. An unusual plant and well worth investigation.

Barrel Coneflower - Isopogon trilobus

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Barrel Coneflower - Isopogon trilobus

A common shrub of the Esperance region in near coastal heath. It is very adaptable growing on sandy soil in low-lying areas around freshwater swamps, granite outcrops or flood plains, to deep sand on heath covered hillsides. It also grows in sand over heavier gravel soil, or limestone, where sub-surface moisture is retained for longer periods, but the surface area remains dry and well drained.

Generally the Barrel Coneflower (named after the shape of the seed capsule ie, the cone) develops into an open shrub of around a metre in height (over 3'), although it can reach 2 metres in favourable conditions. The attractive non-prickly foliage usually has pronounced three lobed leaves with soft pink/red new growth, although some forms produce a lime green coloration.

The showy terminal cream to yellow flowers (around 4 cm or 11/2" diameter) are conspicuous from a distance to readily attract birds and insects during September to December when they normally bloom.