Isopogon and Petrophile in THIS ISSUE Disopogon and This Issue of Seed Notes Petrophile Will Cover the Genera the Botanist Robert Brown Isopogon and Petrophile

Home , Isopogon, Isopogon drummondii, Isopogon formosus, Isopogon latifolius, Isopogon uncinatus, Petrophile

No. 18 Isopogon and Petrophile IN THIS ISSUE DIsopogon and This issue of Seed Notes Petrophile will cover the genera The botanist Robert Brown Isopogon and Petrophile. named the genus Isopogon D Description in 1810. The name means equally bearded, which D Geographic refers to the nut that is hairy distribution and all over. Petrophile, which habitat means rock loving, was D Reproductive biology named by Joseph Knight in D Seed collection 1809. The first specimens of this genus were collected D Seed quality from rocky habitats. Very assessment few species of Petrophile are Isopogon formosus ssp. dasylepis. Photo – Anne Cochrane D Seed germination cultivated in spite of their attractiveness, including D Recommended reading Description good floral displays and D interesting foliage variation. Isopogon and Petrophile clustered in numerous small Some species of Isopogon, (family Proteaceae) are very flowers that can be cream, commonly called cone bushes closely related and often yellow or pink. Flowering is or conesticks, have been used difficult to tell apart. Species mainly late spring to early in the cut flower trade and of both genera are woody summer. The distinguishing in amenity plantings. Seed is perennials, ranging from feature of these two genera not generally available for dwarf to medium erect is the fruit, which is a cone. either genus from commercial shrubs up to two metres When the fruit of Isopogon outlets. tall. Leaves can be flat or is ripe, the bracts, or cone D cylindrical, simple or divided, scales, fall away; in Petrophile and soft or pungent. Both they are persistent. Some have flowers in heads or species in the genus Isopogon Below: Isopogon formosus ssp. short terminal or axillary have lignotubers and can dasylepis. spikes that are attached to resprout from rootstock after Below right: Petrophile latericola. the stem or sometimes on fire or cutting. Photos – Anne Cochrane short stems. The flowers are D

Seed Notes 18 page 1 Geographic distribution and habitat Seed collection There are about 35 species Collection of cones from both genera Dof Isopogon and more than is very easy but care must be taken to 50 species of Petrophile. only collect mature cones. Cones turn Both genera are endemic to grey to grey brown when ripe and lose Australia. Most species are their old floral parts. They are usually confined to south-western ripe six months after flowering. Use Australia, occur on a range secateurs to cut the cones from the of soil types and grow shrub. This is often necessary in plants in heaths or woodlands that produce axillary cones that are over granite or gravel, or hard to remove from the branches. In Approximate distribution of in heath on sandy soils Isopogon and Petrophile in Isopogon, the cones will disintegrate over laterite. In the east of Australia. with age and the seed will be released. Australia, species are found The seed does not extract as easily from on sandstone soils in higher Petrophile and may need to be pulled rainfall areas. They mainly occur in temperate to semi-arid zones out with a pair of forceps. on acid soils. The dieback disease, Phytophthora cinnamomi, D is threatening the survival of many species that occur in high rainfall areas.D

Reproductive biology DThe cone consists of many fruits or nuts which contain a single seed. Seeds of both Isopogon and Petrophile are wind dispersed with the hairiness of the fruits helping dispersal. It is likely that flowers of both genera are insect or bird pollinated. It is also thought that mammals such as bush rats and honey possums may pollinate species in these genera.D

Below: Isopogon uncinatus. Photo – Anne Cochrane Below right: Petrophile linearis. Photo – Sue Patrick

Seed Notes 18 page Seed quality assessment It is sometimes hard to find the small fruits containing the seed Dof Isopogon within the cone. The seed is surrounded by many long silky hairs so pulling apart the cones and finding the seed is tedious. The small fruits of Petrophile are fringed with hairs and the seed within the fruit is flattish. Many ‘false’ fruits are produced in both genera. This means that fruits are formed but are not filled by a seed. Nicking a small corner of the fruit coat will, if present, reveal a seed. Far left: Isopogon formosus ssp. D dasylepis. Left: Isopogon tridens. Above: Petrophile latericola. Below left and below: Isopogon Photo – Anne Cochrane latifolius. Photos – Anne Cochrane DSeed germination Plants of both Isopogon and Petrophile can be grown from seed with variable results. Germination may take several months. Smoke has been implicated in improved germination for some species. Removing the hairs and nicking a small section of the seed coat to reveal the underlying white seed gives good results, provided the seed is not damaged. This cutting away of the seed coat has a tendency to speed up the germination process. D

Right: Germinating seed of Isopogon latifolius. Photo – Anne Cochrane Below: Mature cones of Isopogon drummondii. Photo – Sue Patrick

Seed Notes 18 page Seed Notes for Western Australia

These Seed Notes aim to provide information on seed identification, collection, biology and germination for a wide range of seed types for Western Australian native species.

They have been written and compiled by Anne Cochrane, Manager of DEC's Threatened Flora Seed Centre. Concept by Grazyna Paczkowska. Designed by DEC’s Graphic Design Section.

The Seed Notes are available from Above: Isopogon asper fruit. Photo – Sue Patrick www.naturebase.net

Recommended reading Seed Notes Elliot, W. R. and Jones, D. L. 1984. George, A. S. 1984. An Introduction to the are published by Encyclopaedia of Australian Plants Suitable Proteaceae of Western Australia. Kangaroo the Perth Branch of the Dfor Cultivation. Volumes 5 and 7. Lothian Press, Sydney. Wildflower Society of Publishing, Melbourne. Western Australia (Inc.) Sainsbury, R. M. 1987. A Field Guide to with assistance from Foreman, D. B. 1995. Petrophile. Flora of Isopogons and Petrophiles. University of the Western Australian Australia 16, 149-193. CSIRO, Melbourne. Western Australia Press, Perth. Lotteries Commission Foreman, D. B. 1995. Isopogon. Flora of Sharr, F. A. 1978. Western Australian Plant and the Department Australia 16, 193-223. CSIRO, Melbourne. Names and their Meanings. A Glossary. of Environment and University of Western Australia Press, Perth. Conservation (DEC).

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Seed Notes 18 page