Under the mediterranean-type climate, amaryllid geophytes are absent from Western Australia despite being typical in Chile, speciose in California, and diverse in South Africa

INTRODUCTION

Geophytes are defined as terrestrial perennial plants of which the above-ground parts die down to ground level each year. All cryptophytes possess hidden storage organs, and geophytes are those cryptophytes other than aquatic plants or those inhabiting permanently wet ground.

The widespread family Amaryllidaceae (https://en.wikipedia.org/wiki/Amaryllidaceae), which now includes Alliaceae, is mainly geophytic.

Amaryllids (https://link.springer.com/chapter/10.1007/978-3-662-03533-7_11)

  • include some of the most spectacular and useful geophytes on Earth, and
  • are more specialised for bulbs (as opposed to rhizomes, corms or other stem-tubers) than are other geophytic monocotyledonous families.

The geophytic growth-form (see https://cnps.org/wp-content/uploads/2018/03/FremontiaV44.3.pdf) is effectively drought-deciduous. Thus, it seems particularly suited to the mediterranean-type climate, defined as having dry summers and rainy winters.

Given the above facts, it is unremarkable that various amaryllid geophytes occur under the mediterranean-type climate on various continents.

It is equally unremarkable that the local floras of amaryllidaceous geophytes are different. Only one genus is shared among the mediterranean-type climates of Chile, California, or South Africa. This is Allium, which has many spp. in California and one in South Africa.

However, what is remarkable is that (in order of most to least surprising)

RESULTS

Please see all the relevant genera, listed below. The most anomalous finding is the lack of any representatives in western Australia.

In California, the only indigenous genus is Allium, which in Eurasia has produced the domestic onion, chives, scallion, shallot, leek, and garlic.

I am unsure whether any species of Crinum qualifies as a geophyte. This is because this genus is associated with wet ground.

DISCUSSION

The single most powerful factor in the environment, for explaining the ecological distribution of amaryllid geophytes, is nutrient-richness, particularly the concentration of available phosphorus and zinc in the topsoil.

Wildfire is involved in this framework, because nutrient-poor soils tend to have flammable vegetation, dependent on fire for nutrient-cycling via ash.

The relationship between amaryllids and the fertility of soils helps to explain why this is the only family of monocotyledonous plants that has been agriculturally successful, as domesticated food-crops (particularly six spp. of Allium, https://en.wikipedia.org/wiki/Allium).

Of all the regions of mediterranean-type climate on Earth, that in Chile is the nutrient-richest and the least fire-prone. It can thus be seen as a 'standard' for the incidence of amaryllid geophytes, which are represented here by 11 genera.

Soils in California are nutrient-rich on alluvia, but somewhat impoverished (or imbalanced in the case of serpentine soils) elsewhere. The many spp. of Allium here cover a wide range of environments, including the Central Valley (https://www.inaturalist.org/taxa/59784-Allium-serra). I know of no species with any particular relationship to wildfire.

In the small region of South Africa that has the climate in question, soils are divided between nutrient-poor (on sandstone, quartzite, and deep sand) and moderately nutrient-rich (on shale and slate). Amaryllid geophytes here are associated mainly with relatively nutrient-rich soils and vegetation somewhat protected from wildfire.

However, a few species, particularly of Cyrtanthus, show a clear relationship to fire (https://www.inaturalist.org/taxa/583402-Cyrtanthus-ventricosus).

Please see https://www.semanticscholar.org/paper/Role-of-Fossorial-Animals-in-Community-Structure-of-Cox-Contreras/efa737f295adbfae1412a6b599a9514fcc031121 and https://link.springer.com/chapter/10.1007/978-1-4612-2490-7_16.

In Chile, the subterranean rodent Spalacopus cyanus (https://www.inaturalist.org/taxa/45913-Spalacopus-cyanus) specialises on Leucocoryne (https://academic.oup.com/jmammal/article-abstract/51/3/592/832037?redirectedFrom=fulltext&login=false and https://www.inaturalist.org/taxa/367272-Leucocoryne-ixioides and http://rchn.biologiachile.cl/pdfs/1993/3/Contreras_1993.pdf).

In California, the subterranean rodent Thomomys bottae eats Allium, but only as a small part of a diet that includes greens and roots.

In South Africa, the mole-rats Georychus capensis (https://academic.oup.com/mspecies/article/doi/10.1644/799.1/2600528?login=false) and Cryptomys hottentotus specialise on the tubers of geophytes. However, amaryllids do not feature prominently in their diets. In this region, the large rodent Hystrix africaeaustralia (https://ielc.libguides.com/sdzg/factsheets/cape-porcupine) - which has no counterparts in the relevant regions on other continents- may be as important as mole-rats in the consumption of the bulbs of amaryllids.

CHILE

LEUCOCORYNE
https://en.wikipedia.org/wiki/Leucocoryne
https://en.wikipedia.org/wiki/Gilliesieae#:~:text=Gilliesieae%20is%20a%20tribe%20of,as%20a%20subfamily%20or%20tribe.

PHYCELLA (formerly Rhodophiala)
https://en.wikipedia.org/wiki/Phycella
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:194546-2
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:66595-1

ZEPHYRANTHES
https://en.wikipedia.org/wiki/Zephyranthes
https://www.pacificbulbsociety.org/pbswiki/index.php/zephyranthes
https://www.ornamentalbreeding.nl/FOB_6(SI1)129-139o.pdf

GILLIESIA
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77183077-1

TRISTAGMA
https://www.pacificbulbsociety.org/pbswiki/index.php/Tristagma
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:258948-2

NOTHOSCORDUM
https://www.pacificbulbsociety.org/pbswiki/index.php/Nothoscordum
https://florabase.dpaw.wa.gov.au/browse/profile/1381
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:130726-3

RHODOLIRIUM
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:20011344-1
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:20011344-1/images

MIERSIA
https://www.pacificbulbsociety.org/pbswiki/index.php/Miersia
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:538320-1
https://www.researchgate.net/publication/351850606_Miersia_putaendensis_sp_nov_Gilliesieae_Amaryllidaceae_a_new_species_endemic_to_Central_Chile

TRAUBIA
https://www.pacificbulbsociety.org/pbswiki/index.php/Traubia
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:256509-2
https://en.wikipedia.org/wiki/Traubiinae

PAPPOSOA
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77210018-1
https://chileanendemics.rbge.org.uk/taxa/paposoa-laeta-phil-nic-garc%C3%ADa

LATACE
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77151813-1
https://www.researchgate.net/publication/287995257_The_reinstatement_of_Latace_Phil_Amaryllidaceae_Allioideae

CALIFORNIA

ALLIUM
https://www.inaturalist.org/taxa/75340-Allium-campanulatum
https://en.wikipedia.org/wiki/Allium
https://en.wikipedia.org/wiki/Allium_munzii
https://www.inaturalist.org/taxa/579573-Allium-dregeanum

SOUTH AFRICA

ALLIUM
https://pza.sanbi.org/allium-synnotii#:~:text=Allium%20synnotii%20is%20the%20only,(Christenhusz%20et%20al%202017).
https://en.wikipedia.org/wiki/Allium_dregeanum
https://www.inaturalist.org/taxa/579573-Allium-dregeanum

BRUNSVIGIA
https://en.wikipedia.org/wiki/Brunsvigia

HAEMANTHUS (in part)
https://en.wikipedia.org/wiki/Haemanthus

AMARYLLIS
https://www.inaturalist.org/taxa/61827-Amaryllis-belladonna

CROSSYNE
https://www.inaturalist.org/taxa/367438-Crossyne-guttata
https://en.wikipedia.org/wiki/Crossyne

NERINE (in part)
https://en.wikipedia.org/wiki/Nerine

SCADOXUS
https://www.inaturalist.org/taxa/153154-Scadoxus-puniceus

GETHYLLIS
https://en.wikipedia.org/wiki/Gethyllis

BRUNSVIGIA
https://en.wikipedia.org/wiki/Brunsvigia

CYRTANTHUS
https://en.wikipedia.org/wiki/Cyrtanthus
https://www.inaturalist.org/taxa/583402-Cyrtanthus-ventricosus
https://www.inaturalist.org/taxa/583363-Cyrtanthus-carneus
https://www.inaturalist.org/taxa/583383-Cyrtanthus-leucanthus
https://www.inaturalist.org/taxa/474292-Cyrtanthus-angustifolius
https://www.inaturalist.org/taxa/583371-Cyrtanthus-fergusoniae
https://www.inaturalist.org/taxa/583365-Cyrtanthus-collinus
https://www.inaturalist.org/taxa/583391-Cyrtanthus-odorus
https://www.inaturalist.org/taxa/482833-Cyrtanthus-mackenii
https://www.inaturalist.org/taxa/1396579-Cyrtanthus-novus-annus
https://www.inaturalist.org/taxa/436175-Cyrtanthus-sanguineus
https://www.inaturalist.org/taxa/583375-Cyrtanthus-guthrieae

STRUMARIA
https://en.wikipedia.org/wiki/Strumaria
https://www.inaturalist.org/taxa/559988-Strumaria-spiralis

HESSEA
https://en.wikipedia.org/wiki/Hessea

CRINUM
https://www.inaturalist.org/taxa/135361-Crinum-moorei
https://www.inaturalist.org/taxa/429305-Crinum-macowanii

AMMOCHARIS (is this really geophytic?)
https://www.inaturalist.org/taxa/361683-Ammocharis-longifolia

Apodolirion does not reach the mediterranean-type climate

SOUTH AUSTRALIA

Calostemma
https://en.wikipedia.org/wiki/Calostemma
https://en.wikipedia.org/wiki/Calostemma_purpureum
https://www.inaturalist.org/taxa/548271-Calostemma-luteum

Crinum marginally present (https://www.inaturalist.org/taxa/548270-Crinum-flaccidum)

WESTERN AUSTRALIA

NIL

Posted by milewski milewski, December 06, 2022 02:04 AM

Comments

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

@tonyrebelo
Is any species of Tulbaghia geophytic?

Posted by milewski about 2 months ago (Flag)

I think they are all bulbous, herbaceous perennials.

Posted by tonyrebelo about 2 months ago (Flag)

Tulbaghia (https://www.pacificbulbsociety.org/pbswiki/index.php/Tulbaghia) does not qualify as a geophyte under the mediterranean-type climate in South Africa. It has largely abandoned the bulbous storage organ that is typical of amaryllids. The only geophytic species occurs in tropical southern Africa, where the dry season is in winter.

Posted by milewski about 2 months ago (Flag)

The genus Allium is mainly bulbous, but does also feature rhizomes and swollen roots.

Posted by milewski about 2 months ago (Flag)

The physical environmental conditions favouring geophytes in general, and edible, fast-growing geophytes in particular, are not clearly understood.

However, they appear to be a) moderate status of soil nutrients (richer would favour annuals, while poorer would favour woody plants), b) sufficient sulphur, c) a certain range of ratios of nitrogen to phosphorus, d) climates in which there is a dry season, and a growing season cool enough to limit rates of growth, e) promotion of cycling of nitrogen by fog, f) soils other than sand or clay, and g) frequent, mild fires occurring in a favourable season.

Posted by milewski about 2 months ago (Flag)

Quite a lot of Cape Bulbs seem to occur in both Renosterveld (shale) ad Fynbos (sandstone). Among Cape Plants , geophytes seem to be less tied/restricted to geology/soils than most other growth forms (other than forest species). Many (but not all) are post-fire specialists, occurring in 1 year or 1-3 year windows. Some "bulbs" that extend into old veld, tend to have more persistent leaves.

Posted by tonyrebelo about 2 months ago (Flag)

@ellurasanctuary

Hi Brett and Marie,

Does Crinum occur in your general area? Are you familiar with that genus?

With thanks from Antoni

Posted by milewski about 2 months ago (Flag)

Only Crinum flaccidum, which is native, http://syzygium.xyz/saplants/Amaryllidaceae/Crinum/Crinum_flaccidum.html
I've not seen it before.

Posted by ellurasanctuary about 2 months ago (Flag)

I dont know if it applies to all Amaryllids, but some of them have really potent poisons that even porcupines and molerats wont touch. The problem of storing water over summer for early flowering in autumn, makes bulbs prime sources of water for many animals. Whereas many Amaryllids have hidden bulbs (or at least subterranean - with some shallow and some deep), some dont bother hiding, and are huge and fully exposed. Boophone (not listed above) - meaning Ox-slayer - is one such example (it may be the only one?).

Whatever, what has not been mentioned above is that the Amaryllids store water as well as starch (my feeling is that the Irids store only starch). This allows many of them to flower when other geophytes have to replenish reserves and flower later in the season (although there are many early autumn flowerers in both the Iridaceae and Orchidaceae - but I have no idea of the proportions of autumn/winter/spring (and summer) flowerers in these families, although when one thinks of later summer or early autumn flowering species in the Cape, it is largely Amaryllids).

Posted by tonyrebelo about 2 months ago (Flag)

@tonyrebelo

Many thanks for these intriguing points, which will give plenty of food for thought.

One immediate thought:

Bulbs (typical of amaryllids) are formed essentially from leaves, whereas the various kinds of stem-tuber are formed from stems. In general among plants, leaves lend themselves to succulence more than stems do, for the obvious reason that stems are mainly support structures, inherently fibrous. Some stem-tubers do store water (e.g. Solanum tuberosum), but most emphasise starch rather than water. Root-tubers seem like bulbs in their proclivity to store water, i.e. to be succulent.

Given this link between succulent foliage and the succulent 'leaves' of bulbous plants, it would be interesting to examine the correlation between succulence in the flora and the incidence of bulbous geophytes. Succulent karoo bears out the association, and Chile is another region where both succulents and bulbs are common. California less so, because it has a fair incidence of bulbous geophytes, but not much foliar succulence. Australia certainly bears out the association, because it is extremely poor in succulents (other than halophytes) and also extremely poor in bulbous geophytes.

Posted by milewski about 2 months ago (Flag)

Add a Comment

Sign In or Sign Up to add comments