California Avocado Society 1995 Yearbook 79: 205-209 botanical relatives of the avocado in australia

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California Avocado Society 1995 Yearbook 79: 205-209 





C.A. Schroeder 

Professor of Botany-Emeritus, Department of Biology, University of California, Los 



The recent publication, "Fruits of the Rain Forest," has provided a beautifully illustrated 

account of a portion of the extensive native flora of the Queensland area of Australia


Many of the species have been unknown until recently, except to the local people of the 

area. Only a few of these fascinating and attractive ornamental and possibly otherwise 

useful species have been introduced into California. Among the several plants bearing 

colorful and interesting fruits illustrated in this publication are several fleshy fruits which 

have been known to some extent for their potential value as crop plants. For example, 

the Burdekin plum (Pleiogynium timorensis-Anacardiaceae) and the Johnstone River 

Satinash  (Syzygium erythrocalyx-Myrtaceae) and a few other species which are 

presently under trial for their attractive fruits. The edibility of the fruits of most of the rain 

forest species is not well known, and a few are listed as questionable or specifically 

poisonous. No mention is made concerning the potential value of any of the species for 

use in research and other investigations such as rootstocks for tree crop plants. 

Among the Australian Lauraceae, the botanical family in which the avocado is classified, 

are three major genera which could be of potential value in research programs on the 

avocado. The genera Endiandra, Beilschmedia, and  Cryptocarya  are found in the rain 

forests of northeastern Australia generally as large trees, presently only utilized for 

some of their finer timber woods in the lumber trade


. Another large tree of possible 

value as rootstock are species of Litsea,  the "laurel" of commerce which is also used 

primarily for its fine wood. 

Some trees of Endiandra encountered in the native bush of Queensland can be easily 

and mistakenly identified as "feral" avocado. The tree itself is large, sometimes growing 

up to 90 feet or more in height. The leaf of this evergreen species is very similar to that 

of the ordinary avocado in size and shape and with a glossy surface. The fruit is often 

large, up to 2 or 2 1/2 inches in diameter, and green in color. The fruits of some species 

may develop a red, yellow, or russeted surface. At first glance and at a distance, one 

might identify some of the Endiandra  trees as seedling forms of the well known Nabal 

avocado. A closer examination of the fruit indicates it has a comparatively thin pericarp 

of fleshy tissue and a very thick stony layer of tissue surrounding the large seed. 

Apparently the fruit is not eaten except by some animals, but it is not reported to be 

poisonous. The large seed is reported to have been roasted and eaten by some 

Aborigines. Some species such as Endiandra palmerstonii have been found to be 

drought and frost tender. 


Sketches of fruits of Lauraceae From Australian rain forest (after Cooper):  

Neolitsea delbata. B - Lindera queenslandia. C - Endiandra anthropophagorum. D - 

Beilschmedia castrisinensis. E - Litsea leefeana. F - Cryptocarya oblata. 


Cooper's book lists 19 species of Endiandra which occur in the Queensland rain forest. 

These are generally known locally as "walnuts," with an associated descriptive 

character such as "brown walnut," "gully walnut," "hairy walnut," etc. Other walnuts have 

such commonly associated names as Northern rose, candle, coach, ball-fruited, buff, 

Noah's, rose, and Sankey's. The derivation of the use of "walnut" as a common name 

for this fruit is suggested by the hard and thick endocarp tissue which surrounds the 

seed and the non-edible fleshy outer portion of the fruit. The fruits of several species of 

Endriandra  illustrated by Cooper are quite large. The fruits of Endriandra 

anthropophagorum  and  E. insignis are 2


1/2  inches in diameter and spherical in form. 

The fruit of E. microneura is long-oval in shape and about 2 1/4 inches in length. None 

of the fruits are said to be edible. Nearly all of the trees of these species are tall 

reaching heights up to 30 meters or more under rain forest environment. 

Some species of Beilschmedia also become large trees and bear large size fruit. 

Beilschmedia castrisinensis produces a large, spherical black fruit about 3 inches in 

diameter. The seven species of Beilschmedia are described as large trees and with 

various sized fruits none of which are said to be edible. The 12 species of Cryptocarya 

are commonly known as "laurels." Some of these trees are very large, up to 70 or more 

feet tall. They provide woods of excellent quality which are used in furniture and interior 

finishing. The black fruits are small, ½ to ¾ inches long, and are eaten only by animals. 

One species of Litsea  is described as a tree reaching 80 feet. The fruits of Litsea 

leefeana  commonly known as "Bollywood," are inedible, small oval, and purple black, 

about one inch long and seated in a cup. Still another large tree in the rain forest is 

Neolitsea which produces a small red fruit about ½ inch in diameter, borne in clusters. 

Among the other member of Lauraceae found in the rain forest is the woe-vine

Cassytha filiformis a semi-parasitic vine which climbs over other vegetation much as 

common dodders (Cuscuta  spp.-Convolulaceae) which are found throughout many 

parts of the world. 

The above brief descriptions of some of the more prominent botanical relatives of 

avocado found in the Australian rain forest are given to call attention to investigators 

and others of some comparatively newly described species of Lauraceae which could 

be of potential value in research programs on the avocado. Some of the materials could 

prove of use as attractive ornamental specimens. The use of such species could be of 

especial value in investigations on rootstocks and possibly for some of the breeding 

programs in avocado research. Some reports have indicated that Endriandra has been 

tried as a rootstock for avocado, but has not been successful


. Perhaps other species 

of  Endriandra  should be included in grafting or budding trials, using a wider range of 

materials or repeating the trials under various conditions. An example of drawing false 

conclusions from limited experiences is that noted when Persea scheideana was first 

tried as a rootstock for avocado. Wilson Popenoe reported in a personal letter that the 

coyo (Persea scheideana) tested as a rootstock in Honduras, "lacked compatibility' and 

that "eventually the trees failed to develop satisfactorily." Later, this same species was 

found to make excellent rootstock for several cultivars of avocado when tested in South 



. Examples of the utilization of species of fairly distant botanical relatives for 

rootstock in fruit cultivars is found in the citrus group. A major and important rootstock 

for cultivars of the evergreen species of sweet orange (Citrus sinensis), grapefruit  (C. 

paradisi),  mandarins  (C. reticulata) and other edible citrus selections, is the deciduous 

species  Poncirus trifoliata, which itself produces fruits which are generally considered 

as inedible. One might not expect this combination of an evergreen species grafted on a 

deciduous form to be successful or of particular advantage to the citrus grower. The 

highly beneficial effects of the dwarfing effects of the trifoliate rootstock in this case is 

definitely of value. Another example of graft compatibility between species apparently 

widely separated in respect to botanical characters is the family Rosaceae. It is a 

common practice to propagate cultivars of the evergreen loquat (Eriobotrya japnica) on 

rootstocks of the deciduous species the quince (Cydonia oblonga). This combination 

results in a comparatively dwarfed, yet very fruitful and valuable tree for the grower. 

Thus, one should not reach conclusions on problems of grafting compatibility between 

any two species of woody plants without considering trials using a wide range of 

materials and a sufficient number of trials under various environmental conditions. The 

constant challenge of seeking new avocado rootstocks which exhibit disease 

resistance; adaptability to adverse soil conditions such as high salinity, poor drainage; 

or other soil limitations, requires that all possible botanical relatives of the avocado be 

explored in respect to their budding and grafting affinity and long time compatibility. 

Some of the recently described rain forest species of Lauraceae must be considered for 

such trials. 



1. Baker, R.T. 1919. The Hardwoods of Australia,. Dept. Educ., N.S.W. 

2. Cooper, W., and W.T. Cooper. 1994. Fruits of the Rain Forest. R D Press, Australia 

3. Schroeder, C.A. 1990. Useful fruits of avocado relatives. Calif. Avocado. Soc. 

Yearbook 74:243-249. 

4. Schroeder, C.A. 1987. Avocados in Australia. Calif. Avocado Soc. Yearbook 72:145-


5. Schroeder, C.A., and M. Schroeder. 1981. Some historical aspects of the avocado in 

Australia. Calif. Avocado Soc. Yearbook 66: 119-124. 

6. Fister. D. 1949. The coyo: a rootstock for the avocado.  Calif. Avocado Soc. 

Yearbook 1949:27-31. 

7. Usher, G. 1974. A Dictionary of Plants Used by Man. Macmillan, N.Y. 

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