Geophytes (excluding Orchidaceae) in the region of Sydney, Australia

Any naturalist familiar with the region of Cape Town, South Africa, would find biological affinity with the region of Sydney, Australia.

Both locations lie at the same latitude (33.9 degrees South), and have extensive substrates of sandstone (https://en.wikipedia.org/wiki/Sydney_sandstone and https://en.wikipedia.org/wiki/Table_Mountain_Sandstone).

In both cases, the vegetation on sandstone slopes contains many spp. of fire-prone Proteaceae and Ericaceae. In ravines and at the coast, there are small patches of fire-free forest/thicket, containing shared genera including Podocarpus, Celtis, Diospyros, Maytenus, Elaeodendrum, Myrsine, Cryptocarya, and Cynanchum.

In view of these affinities, I was curious about the similarities and differences in the floras of geophytes (https://www.researchgate.net/publication/229550396_An_overview_of_the_Cape_geophytes), excluding orchids.

Juncaginaceae:

The genus Triglochin contains geophytes, including species or subspecies restricted to South Africa (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77107744-1 and https://www.researchgate.net/publication/46734319_Revision_of_the_Mediterranean_and_southern_African_Triglochin_bulbosa_complex_Juncaginaceae and https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77172374-1 and https://powo.science.kew.org/taxon/77107743-1). A widespread species (https://www.inaturalist.org/taxa/79438-Triglochin-striata), occurring in the Sydney region, may qualify as a rhizomatous geophyte, despite its halophytic and aquatic affinities.

Asphodelaceae:

Bulbine is shared between southern Africa and Australia (https://www.pacificbulbsociety.org/pbswiki/index.php/Bulbine?setskin=pbs_greenish and https://en.wikipedia.org/wiki/Bulbine). It contains several geophytic spp. in the Cape Town region
(https://www.inaturalist.org/observations?place_id=6987&taxon_id=72021&view=species).

Bulbine bulbosa (https://www.inaturalist.org/taxa/516738-Bulbine-bulbosa) has edible tubers, and certainly qualifies as a geophyte (pers. obs.; John Jessop, pers. comm. https://species.wikimedia.org/wiki/John_Peter_Jessop). However, its tubers are confusingly described as roots, bulbs, or corms. Another species indigenous to the Sydney region (https://www.inaturalist.org/taxa/504014-Bulbine-glauca) is not necessarily geophytic.

Asparagaceae:

Geophytic: Thysanotus tuberosus (https://www.inaturalist.org/taxa/122043-Thysanotus-tuberosus and https://apps.lucidcentral.org/plants_se_nsw/text/entities/thysanotus_tuberosus_subsp._tuberosus.htm and https://en.wikipedia.org/wiki/Thysanotus_tuberosus and https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Thysanotus~tuberosus and https://www.yarraranges.vic.gov.au/PlantDirectory/Lilies-Irises/Thysanotus-tuberosus-ssp.-tuberosus)
Not geophytic: Thysanotus juncifolius (https://www.inaturalist.org/taxa/353956-Thysanotus-juncifolius and https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Thysanotus~juncifolius and http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&name=Thysanotus_juncifolius and https://en.wikipedia.org/wiki/Thysanotus_juncifolius)
Thysanotus virgatus is probably not geophytic. It is described as geophytic in https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:542243-1, but as having perennial stems in https://www.inaturalist.org/taxa/862772-Thysanotus-virgatus
and https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Thysanotus~virgatus
https://apps.lucidcentral.org/plants_se_nsw/text/entities/thysanotus_virgatus.htm and https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2897903#gallery.
Not geophytic: Thysanotus manglesianus (https://www.inaturalist.org/taxa/567742-Thysanotus-manglesianus)

probably geophytic https://www.inaturalist.org/taxa/522233-Arthropodium-milleflorum and https://www.inaturalist.org/taxa/1138706-Arthropodium-strictum and https://www.inaturalist.org/taxa/1138705-Arthropodium-fimbriatum and https://www.inaturalist.org/taxa/557457-Arthropodium-minus

Caesia parviflora https://www.inaturalist.org/taxa/323895-Caesia-parviflora
Caesia calliantha https://www.inaturalist.org/taxa/353967-Caesia-calliantha

The genus Sowerbaea contains geophytes with root-tubers. However, the only species occurring in the Sydney region, viz. Sowerbaea juncea (https://www.inaturalist.org/taxa/515898-Sowerbaea-juncea), is described as having fibrous roots and being restricted to 'wet soil'. I infer that it is probably not geophytic.

Colchicaceae:

Burchardia umbellifera (https://www.inaturalist.org/taxa/83628-Burchardia-umbellata) is root-tuberous, and qualifies as geophytic.

Wurmbea dioica https://www.inaturalist.org/taxa/504086-Wurmbea-dioica
Wurmbea biglandulosa https://www.inaturalist.org/taxa/554065-Wurmbea-biglandulosa

Amaryllidaceae:

There is a rich flora of geophytic Amaryllidaceae in the region of Cape Town.
However, the only genus shared with the Sydney region is Crinum.

Cape Town https://www.inaturalist.org/taxa/429305-Crinum-macowanii and https://www.inaturalist.org/taxa/135361-Crinum-moorei

Sydney https://www.inaturalist.org/taxa/135370-Crinum-pedunculatum

However, the species in the Sydney region is specialised for wet ground. It may therefore not strictly qualify as geophytic, given that geophytes are defined as fully terrestrial cryptophytes.

Araceae:

In the Araceae, the only species indigenous to the Sydney region that qualifies as geophytic is Typhonium brownii (https://www.inaturalist.org/taxa/534383-Typhonium-brownii)

Alocasia brisbanensis (https://www.inaturalist.org/taxa/126965-Alocasia-brisbanensis) is too aquatic to qualify as geophytic.

Gymnostachys anceps (https://www.inaturalist.org/taxa/534357-Gymnostachys-anceps) has 'tuberous roots', but does not qualify as geophytic, because its above-ground parts do not die down to ground level seasonally.

Iridaceae:

In the region of Cape Town, there is a bewildering proliferation of geophytic Iridaceae. This family is indigenous to the Sydney region, but the incidence of geophytes could not be more different.

The most speciose genus here, namely Patersonia, is evergreen. So are Libertia paniculata (https://www.inaturalist.org/taxa/417785-Libertia-paniculata) and Libertia pulchella (https://www.inaturalist.org/taxa/323421-Libertia-pulchella).

Dioscoreaceae:

Dioscorea is tuberous but apparently not geophytic. The species indigenous to the Sydney region is Dioscorea hastifolia (https://www.inaturalist.org/taxa/370127-Dioscorea-transversa).

Haemodoraceae:

https://www.inaturalist.org/taxa/864482-Haemodorum-planifolium
https://www.inaturalist.org/taxa/960016-Haemodorum-corymbosum

Hypoxidaceae:

https://www.inaturalist.org/taxa/321134-Hypoxis-hygrometrica
https://www.inaturalist.org/taxa/748411-Pauridia-glabella

Oxalidaceae:

Oxalis corniculata ('bulb absent') is the only indigenous member of this genus in this region. It is not geophytic.

Ranunculaceae:

Clematis has woody stems. I infer that it does not qualify as a geophyte, even if it is tuberous.

Ranunculus: some spp. tend to be aquatic, or restricted to damp ground.

Euphorbiaceae:

The genus Euphorbia includes geophytes (https://www.euphorbia-international.org/journal/pdf_files/EW6-1-sample.pdf and https://www.biotaxa.org/Phytotaxa/article/view/phytotaxa.307.2.5 and https://www.researchgate.net/figure/Habitat-and-morphological-features-of-the-geophytic-Euphorbia-samples-collected-from-10_tbl2_325839822 and https://www.researchgate.net/figure/Inflorescence-features-of-geophytic-Euphorbia-species-collected-from-nine-localities-in_fig3_325839822 and https://www.tandfonline.com/doi/abs/10.1080/00837792.2018.1476207 and https://www.jstor.org/stable/4109908). However, the two spp. recorded in the Sydney region, namely Euphorbia drummondii and Euphorbia sparrmannii, are not geophytic.

Fabaceae:

Glycine clandestina (https://www.inaturalist.org/taxa/321122-Glycine-clandestina) and Glycine tabacina (https://www.inaturalist.org/taxa/369513-Glycine-tabacina) are both indigenous. This genus has potential for the geophytic growth-form, but neither species seems to qualify.

Campanulaceae:

In the Cape Floristic Region, the genus Wahlenbergia contains at least two rhizomatous spp. (suffruticosa and subulata, https://www.researchgate.net/publication/235652480_A_new_species_of_Wahlenbergia_from_Western_Cape_South_Africa) that are potentially geophytic. This genus is indigenous to the Sydney region, where e.g. Wahlenbergia stricta (https://www.inaturalist.org/taxa/131651-Wahlenbergia-stricta) is described as possessing 'tubers', and Wahlenbergia capillaris (https://www.inaturalist.org/taxa/916652-Wahlenbergia-capillaris) is described as possessing a 'thickened taproot'. Both spp. are potentially geophytic.

Asteraceae:

The widespread genus Lagenophora contains geophytes (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:117539-3 and https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:117632-3) and has been described as 'stoloniferous' (https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Lagenophora). The spp. occurring in the Sydney region, viz. Lagenophora stipitata (https://www.inaturalist.org/taxa/323152-Lagenophora-stipitata), Lagenoohora sublyrata (https://www.inaturalist.org/taxa/1094266-Lagenophora-sublyrata), and
Lagenophora brachyglossa (https://www.inaturalist.org/taxa/1377729-Lagenophora-brachyglossa), are potentially geophytic.

Microseris walteri (https://www.inaturalist.org/taxa/1132139-Microseris-walteri) is well-known for its edible root-tubers. I assume that it qualifies as a geophyte.

Convolvulaceae:

Convolvulus is known to possess rhizomes. However, the above-ground stems tend to be woody. I assume that the spp. indigenous to the Sydney region, viz. https://www.inaturalist.org/taxa/526700-Convolvulus-angustissimus and
https://www.inaturalist.org/taxa/210190-Convolvulus-erubescens, are not geophytic.

DISCUSSION

For naturalists familiar with the region of Cape Town, it may seem more appropriate to focus on the region of Perth (https://en.wikipedia.org/wiki/Perth). This is because Perth lies on a western coast, and resembles Cape Town in having a mediterranean-type climate.

However, the climates of Cape Town and Perth (32 degrees South) differ considerably, because

  • these locations differ in latitude by two degrees, and
  • the marine currents west of the coasts are cold (bringing fog) in the case of Cape Town vs warm (bringing thunderstorms) in the case of Perth.

Furthermore, all parts of Australia with mediterranean-type climates (including South Australia) have so little topographic relief that any ecological comparison with the Cape Peninsula is limited.

It is perhaps for these reasons that there is, overall, as much botanical similarity between the region of Cape Town and the region of Sydney as there is between the region of Cape Town and the regions of Perth or Adelaide.

Despite the tropical influences on the climate at Perth, the flora completely lacks certain tropical elements that reach Cape Town, in families and genera such as Ebenaceae, Apocynaceae, Sapotaceae, Metteniusaceae, and Rubiaceae.

With respect to geophytes, the tropical affinity can be seen in the occurrence of Amaryllidaceae and Araceae in the Sydney region. These families have not naturally penetrated the mediterranean-type climate in Western Australia.

Crinum occurs on alluvial landforms in the Murray Valley, and in the Flinders Range (https://en.wikipedia.org/wiki/Flinders_Ranges), both in South Australia (https://www.inaturalist.org/taxa/548270-Crinum-flaccidum). Both locations are marginal to the mediterranean-type climate. In Western Australia, the closest approach by Crinum to the mediterranean-type climate is near Carnarvon (https://florabase.dpaw.wa.gov.au/browse/profile/1491).

According to the Flora of Australia, Crinum in semi-arid Australia has a bulb of diameter 7-10 cm, and is restricted to 'wet places'. It occurs on clay flats in botomlands, where water tends to accumulate. However, in mesic tropical Western Australia (the Kimberley region, https://en.wikipedia.org/wiki/Kimberley_(Western_Australia)) Crinum often occurs where the parent rock is sandstone (according to labels in the Western Australian Herbarium).

In northern Western Australia, with rainy summers and dry winters, the amaryllidaceous geophyte Proiphys (formerly called Eurycles alba) occurs on bauxitic duricrust (J S Beard, pers. comm.), as well as clay over basalt (specimen labels in Western Australian Herbarium).

Posted by milewski milewski, December 03, 2022 11:08 AM

Comments

But Sydney is humid, hot and has summer rainfall. Surely you should compare Perth and Cape Town rather.
I felt quite at home on the beach in Perth: the same species as Cape Town. But I was there too late for the geophytes.

Posted by tonyrebelo about 2 months ago (Flag)
Posted by milewski about 2 months ago (Flag)

edible underground storage organs described as rhizomes: https://www.inaturalist.org/taxa/409520-Arthropodium-cirratum

Posted by milewski about 2 months ago (Flag)

In the St Lucia area of Kwazulu-Natal, Hypoxis (which tastes extremely bitter) is known to be eaten by Potamochoerus larvatus. The local spp. include Hypoxis hemerocallidea, Hypoxis angustifolia, and Hypoxis filiformis.

Posted by milewski about 2 months ago (Flag)

Comparison of Cape Town with Sydney for bulbs seems spurious. There is a reason why bulbs occur in Cape Town: there is a dry season where virtually zero rain falls for 3-4 months in summer. Sydney has rain all year round and no real dry season: so why should there be any species that die down in any season due to rain?
(the other option for dieing down is frost or extreme cold, but I dont think that that applies in Sydney either. I am surprized that you found any geophytes).

Posted by tonyrebelo about 2 months ago (Flag)

@tonyrebelo @jeremygilmore

I take your point. However, the situation can perhaps be best understood by framing the deciduousness of geophytes as a life-history strategy, rather than an adaptation to degrees of seasonal drought so great that deciduousness is obligatory.

I offer the following as evidence that many geophytes are 'voluntarily' rather than 'inevitably' deciduous.

There is a category of wetland cryptophytes (typified by Araceae) that are deciduous despite year-round moisture. Crinum in the Sydney region is an example, but so is Zantedeschia in the Cape Town region. Do the crinums in the Cape Floristic region likewise occur in marshy spots? Chasmanthe strikes me as an iridaceous example of a geophyte for which the soil does not really dry out prohibitively in summer.

On the Highveld, all the grasses go dry and brown, even in 'vleis' where, in the dry season, the soil remains moist. It is far from the case that the deciduousness of grasses on the Highveld reflects soils seasonally so dry that evergreenness would not be an option, given a different life-history strategy.

I observed a relevant example during my visit to Ithala near the end of the dry season. At that time, there had been no rain, but - as usual - the managers had burned the grass to produce a 'green pick', crucial for species such as the tsessebe in the absence of bulk-and-roughage grazers such as Syncerus. One could say that the whole management of that reserve, at that time, revolved around 'green pick' produced in the dry season. The fact that the common grasses easily sprang to life in response to fire seems to prove that moisture remains there, in their root-zone. And this was by no means just in vleis.

So, why are the grasses deciduous? Presumably for the same reason that various acacias in southern Africa shoot flowers prolifically, late in the dry season, before any rain falls. Just as the 'green pick' keeps the tsessebe going, so the acacia flowers keep giraffes going.

Looking at this from a converse perpective: coastal sage scrub in California is not necessarily any drier, in summer, than renosterveld. However, the former is dominated by deciduous plants, whereas the latter is not. The deciduousness reflects the fact that coastal sage is phosphorus-richer than renosterveld.

Indeed, where the soil is poor enough, deciduousness is not adopted regardless of how dry the dry season may be. The ultimate expression of this is seen in semi-arid kwongan in Western Australia, where some plants are extremely sclerophyllous (which virtually by definition means evergreen) and others are diallagous (which essentially means a combination of sclerophylly and resurrection of foliage that becomes de-greened without dying during drought).

So, the idea is that, although there is some correlation between the geophytic growth-form and seasonal drought, other factors such as nutrient-richness also matter. In nutrient-rich environments, one can expect some plants (albeit not the dominant ones) to 'choose' deciduousness even where there is ample moisture year-round.

Perhaps an extreme example of this principle is Phragmites australis. This reed is winter-deciduous, which can hardly be attributed to cold, because the climate is far from icy, and other wetland graminoids remain evergreen. I suggest that P. australis 'chooses' to lose its leaves in the wet season as part of a nutrient-enriched niche (consider Faidherbia albida in the same light).

Your further thoughts?

Posted by milewski about 2 months ago (Flag)

@tonyrebelo @jeremygilmore

Another part of my reply:

Orchids are by far the most speciose of the geophytes in southwestern Western Australia.

If it were true that seasonal drought is crucial for geophytic orchids, then one would predict far fewer taxa of orchids in New South Wales than in Western Australia.

However, this does not seem to be the case.

The numbers of taxa of orchids are (http://www.anosvic.org.au/Checklist_of_Australian_Orchids_2nd_Ed_2019.pdf ):

SUMMER DRY
Western Australia 501
South Australia 432

SUMMER NOT DRY
New South Wales 588
Victoria 463

From this it seems that the main geophytic genera, e.g. Diuris, Caladenia, Pterostylis, Thelymitra, etc., are no less speciose in the Sydney region than in the Perth or Adelaide regions, not so?

Posted by milewski about 2 months ago (Flag)

These all go seasonally dormant, shedding their leaves?

As a matter of interest, how many flower without leaves (either before or after leaves are active)?

Posted by tonyrebelo about 2 months ago (Flag)

@tonyrebelo @jeremygilmore @ludwig_muller

Let us take Diuris, for example.

This is a genus of geophytic orchids in which all of the spp. are geophytic, and the plants are larger than in most geophytic orchids in Australia (https://en.wikipedia.org/wiki/Diuris and http://chookman.id.au/wp_orchids/?page_id=946).

In Western Australia, there are 38 spp., of which 11 occur in the Perth region (https://www.roundthebend.org.au/our-environment and https://www.inaturalist.org/observations?place_id=6827&taxon_id=83523&view=species).

(Please see https://waorchidadventures.com/tag/donkey/.)

In New South Wales, there are 33 spp., of which 8 occur in the Sydney region (https://www.inaturalist.org/observations?place_id=6825&taxon_id=83523&view=species).

The incidence of geophytic orchids, in the form of Diuris, is somewhat greater under the climate with dry summers than under the climate with year-round rainfall. However, the incidence under the latter regime (e.g. http://peonyden.blogspot.com/2009/10/yellow-donkley-orchids-two-species.html and http://peonyden.blogspot.com/2009/10/another-donkey-orchid-diuris-as.html) is still far greater than can be explained by the idea that geophytes are mainly adaptive to seasonal drought.

Furthermore, even in Western Australia, Diuris tends to occur in moist sites (https://www.dpaw.wa.gov.au/images/documents/plants-animals/threatened-species/flora_posters/DiurisPurdiei2007556.pdf), such as the edges of swamps of Melaleuca, where the soils do not fully dry out at any time of the year, and where none of the trees, shrubs, or graminoids are deciduous.

Please note how many spp. of geophytic orchids occur in dense forests of eucalypts under all-year rainfall in the region of Melbourne in Victoria (https://www.roundthebend.org.au/our-environment and https://www.parks.vic.gov.au/places-to-see/parks/kinglake-national-park).

Posted by milewski about 2 months ago (Flag)

Willis J H, Fuhrer B A, and Rotherham E R (1975) Field guide to the flowers and plants of Victoria. A H & A W Reed, Sydney. 304 pp.

"The ground growing orchids are possibly most profuse in their occurrence and variety in the Box-Ironbark Forest of the Goldfields (where the substrate is sandstone-slate-quartzite) and in the Heathlands. Grazing and other forms of land utilisation have reduced many species to near if not total extinction."

Useful references:
for box-ironbark forest, http://www.viridans.com/ECOVEG/box-ironbark.htm;
for heathland, http://www.viridans.com/ECOVEG/heathland.htm#:~:text=Heathland%20is%20found%20on%20flat,to%201100%20mm%20a%20year.

In particular, see paragraph 7 in the ref. on heathlands, for information on the orchids.

Heathland in Victoria is more similar than Western Australian kwongan to fynbos.

Posted by milewski about 2 months ago (Flag)

Orchids in grassland on chalk substrates in Britain depend on close herbivory or mowing. These are plants adapted to relatively but not excessively disturbed ground (Synge H, pp. 199-205 in Endangered monocotyledons in Europe and South West Asia).

Posted by milewski about 2 months ago (Flag)

CRINUM

Crinum flaccidum, which occurs in the Murray Valley and the Flinders Range in South Australia, has an ovoid bulb of diam. 7-10 cm (Black J M 1948, Flora of South Australia, part 1: Cyatheaceae-Orchidaceae).

Posted by milewski about 2 months ago (Flag)

Eryngium (Apiaceae) is not generally geophytic. Most spp. occur in South America, but 6 spp. occur in Australia.

Posted by milewski about 2 months ago (Flag)

The orchid genus Cypripedium contains geophytes in Europe and North America. However, at least in this long-lived (up to a century) species, the underground storage organ is rhizomatous, not root-tuberous: https://besjournals.onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2745.1999.00407.x.

Posted by milewski about 2 months ago (Flag)

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