skip to content

Darwin Correspondence Project

From Thomas Belt   12 January 1867

1 Ridley Terrace | New Castle on Tyne

January 12. 1867

rest of first page excised

will enclose it.

With sincere respect | I am Dear Sir

rest of second page excised1


On Esculent Fruits.

The intimate relations existing between the fauna and flora of a country and the dependence of each upon the other are strikingly shewn in the provision of esculent fruits.

These may be divided into two classes— 1st—those in which the seed is surrounded by or attached to a fleshy or juicy pulp more or less palatable and nutritious and 2nd those in which the seed itself is eaten, as food—

The first class may be subdivided into those where the seeds are enclosed in a juicy pulp and pass uninjured through the bodies of the animals eating them and into those where the seeds are attached to or surrounded by a pulpy or fleshy fruit but are not themselves swallowed

To the first of these subdivisions belong nearly all berries. I will take my illustration of the relations subsisting between them and the animals of a country from Nova Scotia where there is a succession of small fruits throughout the year including the long and severe winter2

First the wild strawberry ripens in June and for about a month is abundant throughout the province   As they begin to fail the ripe raspberries appear and are even more abundant. They last until the beginning of Autumn, when a number of berries resembling the English whortleberry ripen and continue until the winter frosts set in— At the end of Autumn the Tea berry (Coltheria procumbens) ripens its red berries.3 Throughout the long severe winter they may be found by scraping off the snow: their bright red colour making them conspicuous. I have observed them far into the spring when the strawberries were ripening again.

Thus a fare of small berries is provided throughout the year for the small birds & squirrels. At first sight this appears to be entirely for the benefit of the animals but in reality the first intention is the benefit of the species providing the fruits.

In all these berries the seeds are small and hard cased and pass uninjured through the bodies of the birds and are distributed about by them— The pulpy mass surrounding the seeds is a provision to ensure their dissemination. It attains the same object as the hooks on the fruit of the “burs” or the pappus on that of the compositae4

Some considerations follow from this view. A slow improvement of the fruits ought to be brought about for the largest and finest fruits will be eaten in preference to inferior ones. The plant that produced the finest fruits would hold out the greatest premium for the dissemination of its seeds—5

The succession of berries and the ripening of some at an apparently unpropitious season of the year is easily explained— It is manifestly to the interest of an inferior fruit not to come into competition with a superior one   The raspberry has a better chance of being eaten after the strawberry has done fruiting. The tea berry is not a palatable fruit and if it appeared in the Summer or Autumn would be neglected for the more luscious berries then ripening. But in the Winter it has no competitors and by offering itself when there is little else to get it attains the same object as the more attractive fruits in the Summer and Autumn

To the second subdivision, including these fruits whose seeds are not swallowed, belongs the apple, Orange Peach and most of the large fruits— A study of any of these will shew how admirably the distribution of the seed is ensured. The fruit of the Cashew in Brazil is a good illustration.6 It is formed by an enlargement of the seed stalk and is about the size of an apple   The seed is bean shaped and is attached to the end of the fruit by fibres that run through the pulpy mass—


It forms a natural handle to hold the fruit by. To prevent its being eaten itself, it contains underneath the first skin a most acrid oil that ensures its being thrown away as soon as the fruit is consumed— The provision of a handle to a fruit could only be of use in a country where the animals hired to disseminate the seeds had hands. The monkies are I believe the great distributors of these & other Brazilian seeds. Some of them carry away with them as many of the fruits as they can manage—

Many of the Brazilian palms have their hard nuts surrounded by a fleshy pulp to entice animals to carry them away but the cocoa nut palm thriving only on the sea shore and depending for the distribution of its seeds on their being floated away has its nuts covered with a light, bulky envelope.7

In the second division of fruits the seeds are themselves eaten   In many cases this must be prejudicial to the species and there are many expedients to prevent it

The oak the beech and the chestnut are probably benefited by their seeds being buried by squirrels— If only one seed out of a hundred escapes being eaten, it will be amply sufficient for the welfare of the species.

Many small seeds are unintentionally swallowed by herbivorous animals and the plants producing them are thus distributed   The seeds of the common white clover are thus being rapidly spread over Australia.

CD annotations

Top of letter: ‘Thomas Belt | Has visited Brazil’
10.1 The succession … ripening. 10.6] scored pencil
11.1 fruits … swallowed,] scored pencil; ‘Oranges are carried away (Rengger) & peeled by monkeys.’8
Sketch of cashew: ‘Handles for Monkeys’ pencil
12.1 Many of … pulp] scored pencil
12.4 has its … envelope.] scored pencil
15.1 Many small … Australia. 15.3] scored pencil
Bottom of enclosure: ‘On the distribution of Seeds by Animals, Th. Belt | (good)’


The extant portion of the letter has been pasted onto the last sheet of the enclosure.
Belt travelled in 1863 to Nova Scotia, where he worked as superintendent of the Nova-Scotian Gold Company’s mines; he remained there for two or three years (Belt 1888, pp. xvii–xviii).
Belt refers to Gaultheria procumbens, also known as wintergreen.
Burrs are prickly seedcases or flower-heads that easily stick to passing animals. The pappus is a ring of fine hairs attached to achenes or fruits of members of the Compositae; these aid in dissemination by wind.
CD discussed the dispersal of seeds by birds in Origin, pp. 356–65, in the context of geographical distribution; he mentioned colourful seeds in relation to the idea of beauty in Origin 4th ed., p. 240.
In 1866, Belt spent three months in the State of Maranhão, Brazil (Transactions of the Entomological Society of London 5 (1865–7): p. lxxxix).
See Origin, p. 360.
CD refers to a statement in Johann Rudolph Rengger’s Naturgeschichte der Saeugethiere von Paraguay (Rengger 1830). On page 39 of CD’s heavily annotated copy in the Darwin Library–CUL, an annotation next to a discussion of monkeys reads: ‘Beat the oranges to losen rind’ (see Marginalia 1: 699). See Descent 1: 139–40.


Belt, Thomas. 1888. The naturalist in Nicaragua. A narrative of a residence at the gold mines of Chontales; journeys in the savannahs and forests; with observations on animals and plants in reference to the theory of evolution of living forms. 2d edition, revised and corrected. London: Edward Bumpus.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

Origin 4th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 4th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1866.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Rengger, Johann Rudolph. 1830. Naturgeschichte der Saeugethiere von Paraguay. Basel, Switzerland: Schweighausersche Buchhandlung.


MS essay "On esculent fruits" [apparently enclosed in a missing letter].

Letter details

Letter no.
Thomas Belt
Charles Robert Darwin
Sent from
Source of text
DAR 47: 181–9
Physical description
10pp inc †

Please cite as

Darwin Correspondence Project, “Letter no. 5359,” accessed on 21 January 2021,

Also published in The Correspondence of Charles Darwin, vol. 15