Green round fruit found in South Africa, near Zeerust

I'm asking this question for Basil who emailed me. Anyone know what it is?

"I was in the north western part of South Africa, near Zeerust, and was given the attached fruit. It has a hard shell somewhat like a gem squash and is the same size. The pulp is white and has many seeds. What is it? Is it edible? If so when do I know that it is ripe?"
Kind regards,
Basil

 

Okay nevermind, I think  I got it.

Crescentia cujete, the Calabash Tree

Read all about it here

I need a more detailed description of the seeds:

- are they small like melon seeds then it might be a gem squash, edible fruit, only the interior,

- are they relatively large, as thick as fingers, then it may be the monkey apple, also edible fruit,

 

Friendly greetings,

 

Eduard

I'll find out from Basil and get back to you.

Thanks, Alan

Eduard,

Here are Basil's comments and his photos:

--

Some of the fruit has become a very light green, with the interior much as when it was picked in May (cream with an astringent taste – almost no change). Interestingly the pulp oxidizes fairly quickly when exposed to the atmosphere. The seeds have grown much larger though, oval and concave.

Some fruit has gone brown with the interior almost black (looks like a fungus has attacked it). That may explain my comments earlier about the pulp being a black mass?

--

SEED

FRUIT GONE BAD

This is what I recall being called a Monkey orange, a plant of the Strichnos genus.  Given the stated location of Zeerust - I suspect Strychnos cocculoides, S spinosa OR S madagascariensis, but without more information of the plant it was picked from and my copy of "Trees of Southern Africa"  by Keith Coates Pelgrave - I can only make an educated guess. As Zeerust has been given as the geographic origin, it could provide a clue if the distribution maps of Keith Coates Perglave is used.  If overlaps occur in their distribution, then images of leaves, leaf arrangement and maybe even flowers may be required to identify the exact species.

There are apparently 190 species scattered around the world tropics with several species in Southern Afirica.

Commercial Strychnine is harvested from the bark of S. nux-vormic (Indian species) and I recall that the seeds of the monkey orange plant contain varying levels of Strychnine so must be considered poisonous.  The pulp is eaten by monkeys and I believe that in some areas of Africa the pulp of ripe fruit may also be eaten in by the local inhabitants. Do not consume therefore as risk of doing yourself harm is not worth it.

More to be found here: http://en.wikipedia.org/wiki/Strychnos

Spiny Monkey Orange: S spinosa: -  http://www.plantzafrica.com/plantqrs/strychspin.htm

Related species:

Cape Teak: S decussata - http://www.plantzafrica.com/plantqrs/strychnosdecussata.htm

Black Money Orange: S madagascariensis - http://www.plantzafrica.com/plantqrs/strychnosmad.htm

Corky Bark Monkey orange: S cocculoides - http://www.plantzafrica.com/frames/plantsfram.htm

Strychnine Tree: S nux-vomica - http://en.wikipedia.org/wiki/Strychnine_tree