Petrophile biloba

Another thank you is in order to J.G. in S.F.@Flickr for sending along these photographs from the San Francisco Botanical Garden (via the UBC BG Botany Photo of the Day Flickr Pool | original 1 | original 2).

Petrophile, as you might guess, translates into “rock-loving”. This is indeed the case for this relatively short shrubby plants, as they are found in coastal sandy areas, rocky outcrops and inland gravelly areas (though never too far from the coast, perhaps 150km). Common name for plants in the genus used by people in eastern Australia include conesticks, coneflower and conebush. However, in western Australia (the centre of diversity for the genus), these common names aren’t used and it seems they are simply referred to as petrophile.

Petrophile biloba, or granite petrophile, is native to a small area of southwestern Western Australia, near Perth. As noted by FloraBase, this species of hillsides and granite outcrops grows to 2m high. The Australian Native Plant Society provides cultivation and propagation information on it: Petrophile biloba.

Petrophile biloba
Petrophile biloba

19 responses to “Petrophile biloba”

  1. charlene pidgeon

    The first photograph is stunning! What a glorious flower: extraordinary composition, palette, texture. Thank you!

  2. Carolina

    Very, very interesting plant, never seen on this side of the world (by these two not-savy eyes of course). Great pictures.

  3. Quin

    please, where in the garden is it located?

  4. Bob Wilson

    Could someone kindly explain what flower parts we are looking at here? I am confused, not to mention awestruck.

  5. Cambree

    Yes, where is this plant located? The SF Botanical Garden is so big… it would be to see in person.
    Neat looking fuzzy flowers. 🙂

  6. Annie Morgan

    First one is fascinating because of the plant, but a stunning photograph as well. Delightful second photo. Such a joy this daily offering!

  7. CherriesWalks

    is it a bush?

  8. Sara

    It may just be me, but is the first photo displayed “upside down”? Or has the stem bent due to the weight of the flowers? Or does nature allow it to do that to attract pollinators?
    LOVE this site, it’s like a walk in the garden every morning.

  9. Sue Ross

    Oh my the first one is stunning, will it grow in zone 11?

  10. Sue Ross

    I too love this site, thank you so much for the pleasure you give.

  11. Daniel Mosquin

    Sorry, no idea where it’s located. Maybe Jim will post a follow-up comment.
    Yes, it’s a shrub — to 2m.
    I don’t think the first photo is upside-down, per se, but I suspect it does have a different perspective than what you would encounter typically. It looks like the photograph was taken with the leading edge of the branch pointing toward the photographer.
    You can read more about the flowers of Proteaceae via Wikipedia. Essentially, the filaments of the stamens are fused to the tepals (morphologically indistinct sepals and petals). So, where you see a purple glossy linear surface with lines of orange, you’re seeing the inside of a tepal (purple) and the pollen-producing anthers (orange). The yellow bits are the enlarged stigmatic surfaces.

  12. tajalli

    I’d try exploring throughout the Mediterranean region of the arboretum. Warning though – the entire arboretum is undergoing renovation and some areas cannot be accessed.

  13. Helen

    What a lovely way to begin the day.

  14. James Gaither (J.G. in S.F.)

    First, thanks for your kind comments. They are greatly appreciated.
    For those planning a visit to SFBG, Petrophile biloba in located just inside the north entrance (“Friend Gate”) and to the left in a slightly raised bed next to a large explanatory sign pertaining to the collection in the Ancient Plant Garden. I may have my facts wrong about the subject matter of the signage–it may pertain to the adjacent Australian collection. At any rate, P. biloba is a rather leggy, unprepossessing shrub when not in flower and easily overlooked.
    As to the question above about the correct orientation of the first photo, even though it comes from Down Under, it is presented right side up! The flower cluster was in fact pendant. A final word: Although quite spectacular at close range, the flowers are very small (less than 2cm I would guess) and make a rather modest show at normal viewing distances.

  15. Bob Wilson

    Daniel – thanks for your clarification on the flower structure. If the orange is the stigma, then is the enlarged yellow part below it the ovary which is both stalked and exserted?

  16. James Gaither (J.G. in S.F.)

    The precise structure of this flower is far beyond my nonexpertise. A thorough technical discussion of Petrophile flowers can be found through this link:

  17. Quin

    thanks James – I know exactly where you mean – thanks for photos and info

  18. Karen

    Oh big deal. I have tons of these in my garden. (tee hee)

  19. Vera Patrick

    What is the medical ingredient in Petrophile used in Petrophilic Soap prescribed in cases of Nummuler (Many)Exzema ( burning itching many layered Blistering.For washing self. Also Cortisone Ointment with Occlusive( plastic glove) is used at night to draw off moisure from blisters. (That smells like strong Urine….) That was the root of my Question… What is a Petrophile? I lived in British Columbia.. Very rocky ……. I asked, thinking I might be a “Petrophile…..”

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