Almond, לוּז / שָׁקֵד, Amygdalus communis

Kingdom: Plantae

Division: Angiospermae

Class: Dicotyledoneae

Order: Rosales

Family: Rosaceae

Genus: Amygdalus

Species: Amygdalus communis

Originating in the Middle East (Browicz & Zohary 1996), the Amygdalus communis or almond tree most likely gave the neural structure in the brain known as the amygdala its name, due to their resemblance in shape (AbuHasan et al. 2021‏). Like many other edible fruit trees in the Rosaceae family, it is a winter deciduous species, shedding its leaves during the winter months (http://israelalmond.co.il/en). Unusually, however, it blooms before leafing, the fragrant flowers attracting bees that pollinate it, thereby enabling the formation of fruit and seeds (www.wildflowers.co.il/english). The bitterness of wild almonds seeds is due to the presence of cyanide. Cultivation and domestication have stripped the Amygdalus communis of this poisonous element, almonds thus now frequently being regarded as sweet (Browicz & Zohary 1996).

The Hebrew Bible refers to the almond tree by two names: שקד (shaqed) and לוז (luz). According to botanical research field of naming and classifying plants the two names stand for two different trees. The first (שקד [shaqed]) signifies the almond tree, the second (לוז [luz]) the Corylus plant. But since the Corylus is not native to Israel or its surroundings (Feliks 1968), this entry discusses only the שקד (shaqed).

The almond tree is bare and in hibernation between November and February, flowering between early January and late March (https://flora.org.il/en). After flowering, it develops a leafy foliage and turns green. The fruit begin to emerge around March, reaching their maximum size in June. As the heat intensifies over the summer months (July and August), the fruit ripen fully, the drupes split open and the orchard becomes ready for harvesting (http://israelalmond.co.il/en).

A miraculous simultaneous growth of flowers, leaves and ripened fruits on Aaron’s staff. While a tree may bear both flowers, leaves and young fruit during a specific period, the desynchronization between the flowering and fruit ripening seasons (~January‒March vs. ~June – August) makes this a very unlikely occurrence (https://flora.org.il/en; http://israelalmond.co.il/en). The simultaneous flowering and fruit-bearing nature of Aaron’s staff thus falls under the category of the “miraculous.”

White colored inner branches of the almond tree. When healthy, the inner branches are light and bright in color (Mircetich et al. 1976).

Blooming at a unique time. In Hebrew, the name of the tree plays on the root š-q-d, suggesting that it is characterized by its “eagerness to seize opportunities” (Hareuveni 1980). Its early flowering, at the beginning of winter, when there are hardly any other flowers, gives it an advantage over its competitors for pollinators (Michael 1994; London 2001), necessary in light of the bitter taste the amygdalin imparts to the almond plant’s nectar (London 2001; Singaravelan et al. 2005). Amygdalus communis also appears to flower when the temperature of the soil and the water it stores begins rising (Hareuveni 1980). However, while several plant species are affected by high temperatures governing the point at which they flower (Rylski 1972; Hall et al. 1977), the almond tree’s “eagerness” more likely reflects a combination of both factors – the low competition for pollinators and the high temperatures.

Morphological Characteristics

A perennial tree, the Amygdalus communis can survive for 100 years. While customarily growing to between three and eight meters, it can exceed 20 meters under optimal conditions (Gradziel 2011‏).

Flowers. The almond tree is monoecious, male and female flowers appearing on the same tree. Each possesses five petals and 10‒30 stamens. Arranged in groups on the exposed stems, the bisexual flower buds open gradually in pink or white colors (Browicz & Zohary 1996) and are pollinated by bees (www.wildflowers.co.il/english).

Leaves. The leaves are simple, elongated, and toothed, between one and five centimeters long (Browicz & Zohary 1996). During the winter the almond tree has no leaves, and flowering begins (https://flora.org.il/en). Only after flowering, does the tree develops a leafy foliage.

Fruit. The fruit of the Amygdalus communis are known as drupes—fleshy meat with a hard, dry seed released for dispersal. They are thus not nuts, which are hard-shelled fruits that do not open to release the seed (Lorts et al. 2008). Non-spiny (Browicz & Zohary, 1996), with an average length of ca. 3 cm, the fruit has an outer shell that splits in half, usually falling when ripe (www.wildflowers.co.il/english).

Seeds. Almond seeds have hard shells that only split under pressure, remaining on the tree after the fruit shell falls off (www.wildflowers.co.il/english). Wild almond seeds contain a poisonous substance named amygdalin that, when chewed, is converted to a derivative of cyanide. Given the seeds’ bitter taste, this mechanism is suspected to protect them from being eaten by animals (Sánchez-Pérez et al. 2008).

Distribution and Habitat

The almond is distributed across the East Mediterranean and West Irano-Turanian regions (www.wildflowers.co.il/english). Prior to the advent of agriculture, Amygdalus communis appears to have been restricted to the Levant (Israel, Jordan, Lebanon, Syria, most of Turkey), only later becoming naturalized in Middle Asia. The available archaeological evidence also supports its origin along the Eastern Mediterranean shoreline, the first extant evidence of almond domestication dating to Bronze Age sites in the Levant (Browicz & Zohary 1996). Today, California is the primary production region in the world (Badenes & Byrne 2012)—far distant from of the almond’s center of origin, though nowadays almonds are grown worldwide.

The tree is common in maquis and limestone soil from mesic Mediterranean regions to more arid Mediterranean zones (www.wildflowers.co.il/english).

Current distribution map of Amygdalus communis. Taken from www.gbif.org. In this map each point represents the number of species occurrence records. Darker colored points indicate more occurrences.

AbuHasan, Q., V. Reddy, & W. Siddiqui. 2021. “Neuroanatomy, amygdala.” StatPearls: https://www.ncbi.nlm.nih.gov/books/NBK537102/.‏

Badenes, M. L., & D. H. Byrne. Eds. 2012. “Fruit Breeding.” Pages 697‒729 in vol. 8 of Handbook of Plant Breeding. New York: Springer.

Balaguer-Romano, R., A. Barea-Marquez, F. J. Ocaña-Calahorro, J. M. Gomez, E. W. Schupp, J. Zhang, & R. R. de Casas. 2021. “The Potential Role of Synzoochory in the Naturalization of the Almond Tree.” Basic and Applied Ecology 50: 97‒106.‏

Browicz, K., & D. Zohary. 1996. “The genus Amygdalus L. (Rosaceae): Species Relationships, Distribution and Evolution under Domestication.” Genetic Resources and Crop Evolution 43: 229‒47.‏

Feliks, Y. 1968. Plant World of the Bible. Ramat-Gan: Masada.

Gómez, J. M., E. W. Schupp, & P. Jordano. 2019. “Synzoochory: The Ecological and Evolutionary Relevance of a Dual Interaction. Biological Reviews 94: 874‒902.‏

Gradziel, T. M. 2011. “Origin and Dissemination of the Almond.” Horticultural Reviews 38: 23‒80.

Hall, A. E., M. M. Khairi, & C. W. Asbell. 1977. “Air and Soil Temperature Effects on Flowering of Citrus.” Journal of the American Society for Horticultural Science 102: 261‒63.‏

Hareuveni, N. 1980. Nature in our Biblical Heritage. Neot Kedumim: Neot Kedumim.

London, I. 2001. “Competition for Pollination between Cultivated Almonds and Wild Flowers.” MSc thesis, Tel Aviv University.

Lorts, C. M., & T. Briggeman. 2008. “Evolution of Fruit Types and Seed Dispersal: A Phylogenetic and Ecological Snapshot. Journal of Systematics and Evolution 46: 396‒404. ‏

Martinoli, D., & D. Jacomet. 2004. “Identifying Endocarp Remains and Exploring their use at Epipalaeolithic Öküzini in Southwest Anatolia, Turkey.” Vegetation History and Archaeobotany 13: 45‒54.‏

Michael, A. 1994. “The Adaptation of Almond (Amygdalus communis L.) for Blooming under Winter Conditions.” MSc thesis, Tel Aviv University.

Mircetich, S. M., S. K. Lowe, W. J. Moller, & G. Nyland. 1976. “Etiology of Almond Leaf Scorch Disease and Transmission of the Causal Agent.” Phytopathology 66: 17‒24.‏

Rylski, I. 1972. “Effect of the Early Environment on Flowering in Pepper (Capsicum annuum L.).” Journal of the American Society for Horticultural Science 97: 648‒51.‏

Sánchez-Pérez, R., K. Jørgensen, C. E. Olsen, F. Dicenta, & B. L. Møller. 2008. “Bitterness in Almonds.” Plant Physiology 146: 1040‒52.‏

Singaravelan N., G. Nee’man, M. Inbar, & I. Izhaki. 2005. “Feeding Responses of Free-Flying Honeybees to Secondary Compounds Mimicking Floral Nectars. Journal of Chemical Ecology 31: 2791‒804.