A description of the fleshy fruit of Cassine peragua peragua (Celastraceae)

@rcswart @dianastuder @tonyrebelo @jeremygilmore @botaneek @adriaan_grobler @robertarcher397 @benjamin_walton

On 10 May 1999, I encountered a tall shrub of Cassine peragua peragua (https://www.inaturalist.org/observations?place_id=any&taxon_id=598071) in Kirstenbosch Botanical Gardens (https://en.wikipedia.org/wiki/Kirstenbosch_National_Botanical_Garden), where it is indigenous.

Cassine peragua peragua is generally multi-stemmed (https://www.inaturalist.org/observations/71858238 and https://www.inaturalist.org/observations/36701450 and https://www.inaturalist.org/observations/114671303) rather than being a tree, and regenerates vegetatively rather than germinatively.

The leaves (https://www.inaturalist.org/observations/10977814 and https://www.inaturalist.org/observations/65207248) are sclerophyllous, by the standards of the Cape Flora.

This individual was in full fruit at the time (https://www.inaturalist.org/observations/83659421 and https://www.inaturalist.org/observations/76897319 and https://www.inaturalist.org/observations/38747462).

In this Post, I have transcribed my detailed field-notes of the time, on this subpecies of fleshy fruit, interspersing illustrations from iNaturalist.

The ripe fruits were variable in size, 9 X 7.5 mm to 12.5 X 14 mm, and black, with a matt (not glossy) surface (https://www.inaturalist.org/observations/131876171 and https://www.inaturalist.org/observations/14957385).

The average size of the ripe fruits is about 11 X 12 mm. I.e. the diameter exceeds one centimetre, making this among the larger of the succulent fruits of the Cape Flora.

The variation in the size of the fruits, within a single infructescence, presumably facilitates seed-dispersal by birds of various body sizes.

I ate several of the fruits, finding them to be mildly sweet and fairly pleasant, with a 'coffee-bitter' taste. There is no astringency or sourness at either the reddish or the black stage.

I tasted a pale-green fruit (https://www.inaturalist.org/observations/15555922) of less than full size, and found it not to be astringent, even at this stage.

As in many other spp. of fleshy fruits, there is a 'pre-ripe' display (https://www.inaturalist.org/observations/26140400).

In bright sunlight, glossiness and bright red might work best to advertise the fruiting to frugivorous, seed-dispersing birds. However, in the relatively dimly-illuminated conditions applicable to C. peragua peragua, what seems more adaptive is the variegated show of dark/pale plus dull hues, seen in the pre-ripe display.

The fruits are clustered in the infructescences, more aggregated than those of coexisting Olea europaea cuspidata.

The fruits are pale green (paler than the leaves) as they develop (https://www.inaturalist.org/observations/47377371 and https://www.inaturalist.org/observations/76981121). This paleness in its own right makes the growing fruits fairly conspicuous from the start (https://www.inaturalist.org/observations/83296563 and https://www.inaturalist.org/observations/92292223 and https://www.inaturalist.org/observations/120162403).

The young fruits are paler (https://www.inaturalist.org/observations/77015655) than even the underside of the leaf (https://www.inaturalist.org/observations/69364164).

Once they reach full size, they turn dull, blushed reddish (https://www.inaturalist.org/observations/11096698 and https://www.inaturalist.org/observations/96874993). This is conspicuous simply because of the reddish hue, although the colour is really a dull maroon, and passes to dark brown/purple (https://www.inaturalist.org/observations/91120871) in places before all of the green has been replaced by reddish. I.e. the redness is neither vivid nor complete at any stage (https://www.inaturalist.org/observations/94134990).

As soon as the colour starts to change from green to reddish, the fruit softens, so that even a pale-green fruit with blushed ends (https://www.inaturalist.org/observations/77876091) is already half-soft. What this means is that the succulence of a soft, ripe type precedes sweetness. The bitterness remains throughout the ripening process, but astringency is not a feature of this species.

At the reddish stage (https://www.inaturalist.org/observations/90380163), the fruit is soft, but not yet sweet; it has the full succulence and the pleasant coffee-bitter taste, but the sugar seems to form only with the transition to a blackish tone.

The number of seeds is one in some of the fruits, two in most, and three in a few, partly according to the size of the fruit at maturity. The seeds are easily carvable with a thumbnail. Their size is 7 X 4 X 3 mm. They are pinkish, flattened-oval, and small relative to the size of the fruit; i.e. the fruit-pulp is relatively copious.

The average number of seeds per fruit seems to be two, and the two seeds together comprise an estimated 25% of the volume of the fruit. The fruit-pulp is proportionately more ample than that of coexisting Olea europaea cuspidata, because the volume of the 'pip' is less.

The skin of the fruit is tender, but has an integrity separate from the pulp. Whereas the pulp 'melts' in the mouth, the skin does not.

This fruit-pulp is succulent (similar to coexisting Olea europaea cuspidata), with a pale, pinkish colour, different from the dark skin.

The fruit is tender, not tough. Eating the fruits, I found that the fruit-pulp disintegrates in the mouth, releasing the seeds, which can be rapidly spat out. Although the seeds are small, I did not find myself swallowing them.

The ripe fruits seem to collapse in facets in the post-ripe stage. I.e. they lose some of their water, but not with any wrinkling; and even after this dehydration they remain remarkably succulent.

Also see https://www.inaturalist.org/journal/milewski/72610-a-description-of-the-fleshy-fruit-of-celtis-africana-cannabaceae#.

Posted on Νοέμβριος 13, 2022 0815 ΠΜ by milewski