Plasticfruits, part 4: the case of Chenopodium (Amaranthaceae)

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Imagine that you are a naturalist living in a coastal suburb in Australia.

This morning, you take a walk along the beachfront, absent-mindedly noticing an indigenous shrub, a 'berry saltbush', in red fruit ( by the pathside.

This is such a common sight, from Western Australia to New South Wales, that you pay scant attention.

Furthermore, you are not naive enough to be tempted to nibble the fruits.

Later in the day, you sit down to a salad of quinoa ( seeds and lettuce.

And, understandably, it is unlikely to occur to you that berry saltbushes and quinoa belong to the same genus: Chenopodium (Amaranthaceae).

About seven spp. of berry saltbushes have small, flattish, but succulent and conspicuous fruits, adapted for seed-dispersal by birds. These look moderately appetising, but few naturalists who have ever tried them will repeat the experience (please see the first comment below).

In quinoa, by contrast, the fruits, not being fleshy, are tantamount simply to seeds. Who would suspect that this wholesome food-plant could belong to the same genus as berry saltbushes?

And yet this is indeed the case.

This kind of evolutionary plasticity, within genera, is surprisingly common in a wide range of plants.

The nature of flowers is so phylogenetically consistent that plants are classified, to genus level, mainly by their flowers. However, the fruits seem to have an adaptive 'mind of their own', in many and various genera.

At a glance, both berry saltbushes and quinoa show reddish reproductive structures (Chenopodium quinoa: and and and and and

However, in the case of quinoa, these are inflorescences, as opposed to the fleshy fruits of berry saltbushes.

The dichotomy between fleshy and non-fleshy fruits can be seen even within Australia, in the indigenous spp. of Chenopodium.

Several spp., mainly herbaceous and occurring mainly in the semi-arid interior, have fruits similar to those of quinoa ( Were it not the case that quinoa has already been domesticated (in the Andes of Peru), these might be suitable candidates for similar selective breeding as a food-crop.

The variation in the form of the fruits, within Chenopodium, revolves around the remarkable plasticity of both the perianth and the pericarp.

The perianth plays at least three roles in various spp. of Chenopodium indigenous to Australia, viz.

  • reduced to the point of irrelevance, in most of the spp. with fleshy (red) fruits, dispersed by birds, all of which are shrubs,
  • persistent as a hardly-noticeable papery covering around the tiny dry fruit, in the case of several spp. of annuals (e.g. Chenopodium murale,, and
  • persistent as a conspicuous cup-like base for the fleshy fruit, in which the red, glossy inner (= upper) surfaces of the tepals complement the bright hue of the fruit, which dries through orange to yellow (Chenopodium curvispicatum).

For its part, the pericarp takes at least four forms, viz.

The following further illustrate Chenopodium curvispicatum: and and and and

The following are the spp. of Chenopodium, indigenous to Australia, with red fleshy fruits in which the perianth is irrelevant, and the succulent pericarp encircles the seed, rather than spherically enclosing it. These are the various 'berry saltbushes'.

Chenopodium baccatum

Chenopodium candolleanum

Chenopodium spinescens

Chenopodium preissii

Chenopodium wilsonii

Chenopodium parabolicum

Chenopodium gaudichaudianum

to be continued in

Posted on December 09, 2022 03:41 AM by milewski milewski


The ripe fruits of berry saltbushes are unpalatable to humans, in a way not covered by the adjectives available. 'Bitter' is an inept description.

The following is an excerpt from my field-notes, after eating a few ripe fruits of Chenopodium baccatum at Cottesloe beach, Perth, Western Australia.

"These ripe fruits have a ghastly aftertaste, which seems to get worse and worse for tens of minutes. There is a kind of 'chemical burn' sensation, which moves from the mouth into the throat or nose over the minutes. This sensation is somewhat along the lines of 'spiciness' because it has little if anything to do with the taste buds, and would not be pleasantly spicy even in dilution. Birds, the likely dispersers of this species, presumably do not feel this sensation - much as in the case of chili ("

Posted by milewski about 1 year ago

Chenopodium nitrariaceum does not have fleshy fruits:

Posted by milewski about 1 year ago
Posted by milewski about 1 year ago

Chenopodium curvispicatum:
The ripe fruit is displayed while nestling in the persistent perianth, the inner surfaces of the tepals being variably red and glossy, thus enhancing the display. The ripe fruit is often yellowish, producing a conspicuous contrast in hues with the red of the cup of tepals.

Posted by milewski about 1 year ago

Indigenous to southern Africa are Chenopodium hederiforme ( and Chenopodium mucronatum ( and and and Chenopodium phillipsianum ( and

All are annuals.

Posted by milewski about 1 year ago

G'day Antoni;
I'm not sure I see "There seems to be some confusion on the Web between Chenopodium curvispicatum and Chenopodium gaudichaudianum"?
When I look at the links you provided they seem to be segregated appropriately. Can you highlight the specific records that you think are incorrect/swapped?

Posted by ellurasanctuary about 1 year ago


Many thanks for checking, that is most helpful. What do you think of

Posted by milewski about 1 year ago
Posted by ellurasanctuary about 1 year ago
looks ok too, but harder to tell. I'm going by the leaf shape, which in C. gaudichaudianum is longer, C. curvispicatum is rounder.

Posted by ellurasanctuary about 1 year ago

@rfoster I'm not sure, you may be interested in this?

Posted by ellurasanctuary about 1 year ago

On Atlas there seem to be 4 records in the wrong place, Eastern South Australia. We don't get them around here. Not sure about the Eastern States:

This is a good site:

Posted by ellurasanctuary about 1 year ago


Many thanks, you have been most helpful.

What I find confusing is that the two illustrations I queried ( and show fruits lacking the diagnostic feature of the fruit of Chenopodium curvispicatum, viz. the persistent red perianth.

Your latest illustration of Chenopodium gaudichaudianum confirms that, in that species, the perianth is not red.

So, I suggest that the two illustrations in question show gaudichaudianum, not curvispicatum.

Your further thoughts?

Posted by milewski about 1 year ago

Ah, I see. I don't think that is consistently diagnostic.
On our photo you linked to shows some which, while not green, aren't red either while most are red:
I think leaf shape is more important (but harder to tell depending on age, etc).
Also I'm no expert. Pure ameteur, so my "thoughts"/comments need to be considered as such.
But a photo of two different coloured perianth on the same plant/flower stem I think is proof?

Posted by ellurasanctuary about 1 year ago


I am still unsure, for the following reasons.

What I think happens in curvispicatum is that the perianth is initially red and glossy while the fruit is red. Then the fruit turns from red through orange to yellow, and the perianth stays red throughout. Then the fruit is removed or falls off (possibly dispersed secondarily by ants?) and the perianth is still red. Finally, the bare/empty perianth, still attached, fades to pale brownish.

Compare this with gaudichaudianus and all other bird-dispersed spp., in which the perianth is either not in evidence, or present but lacking any conspicuous hue at any stage. In these 'normal' berry saltbushes, the display consists simply of the red fruit itself, which stays red until it is taken by birds or shrivels in desiccation, still attached.

Does your view differ?

Posted by milewski about 1 year ago

I've just gone thru all my photo's to try and find a plant with solid green and solid red tepals on the same plant; I've not been successful.
I now agree that the brown tepals are old, discoloured.

I don't think the yellow fruit is age. I think the bush is either red or yellow fruited. But until we monitor one plant over time we won't know for sure.
I've just gone thru them yet again (~150 photos, ~36 obs) and any in fruit are either red or yellow fruit. Given they fruit over a long period of time, if it was age, I'd expect to see yellow & red fruits on the same plant.

I do have photo's showing the tepals are variable colour. So green and red in on perianth, which leans to saying the colour is not age related.

I suspect tepal colour is variable in C. curvispicatum and perhaps fixed green in C. gaudichaudianus (I'm not familar with this one). So any red = C. curvispicatum, green means either and requires leave shape to differentiate?

While not the best, this photo shows some red, while mainly green tepals:

I'll post a couple of other photo's with more mixed colours. It won't disprove your theories, until we can monitor specific plants showing the yellow fruits & green tepals over time. May take years as we find plants that then we need to monitor the following year or is in flower & fruit at the same time.

Posted by ellurasanctuary about 1 year ago


Again, you have been most helpful, your records are a valuable resource, and your attention to detail enriches all of us here in iNaturalist.

I agree with your assessment, and I suggest that one way to look at the situation is as follows. Chenopodium gaudichaudianum, in having tepals that persist to the fruiting stage, is intermediate between the 'normal' berry saltbushes (in which the tepals are insignificant in this context) and C. curvispicatum (in which the tepals have become functionally part of the 'fruit').

The difference between C. gaudichaudianum and C. curvispicatum is that in the latter (usually but not always) the tepals are red enough to enhance the display of the fruits, which is particularly effective where the fruits are yellow enough to contrast in hue with the red tepals.

The important point for this Post, overall, is that here we have a single genus with a bewildering variety of fruit-forms, despite a presumable consistency of flower-forms. This seems to indicate a basic pattern in the biology of plants, which has caused taxonomic confusion in the past, when many genera (e.g. Muraltia) were falsely split (e.g. Nylandtia, in undue recognition of variation in fruit-form.

Posted by milewski about 1 year ago

No prob's 🙂 We focus on id's and removing weeds from Ellura, that's all my memory banks can handle 😉 LOL

Posted by ellurasanctuary about 1 year ago
Posted by ellurasanctuary about 1 year ago

@ellurasanctuary Hi Brett and Marie, Many thanks for these useful and informative photos, from Antoni

Posted by milewski about 1 year ago


Posted by ellurasanctuary about 1 year ago

In woodland of Eucalyptus gomphocephala (, Chenopodium baccatum ( predictably occurs, as a shade-tolerant, lax shrub. This refers to Quindalup sand (calcareous) blown over Spearwood sand.

Threlkeldia diffusa ( occurs on the windward side of the primary littoral dune, close to the beach. It prefers full sunlight, not the understorey. The vegetation in which T. diffusa occurs is low and windswept, and seldom carries wildfire (unlike woodland of E. gomphocephala, which is subject to wildfire).

An ecologically related amaranth is Enchylaena tomentosa ( However, this hardly occurs naturally in woodland of E. gomphocephala; it is a plant of the interior of southwestern Western Australia, rather than the Swan Coastal Plain.

Posted by milewski about 1 year ago

RHAGODIA PREISSII ( and, which is partly sympatric with Chenopodium baccatum, has not been reallocated at generic level. This implies that the fruits of the two spp are convergent.

Posted by milewski about 1 year ago

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