Botanical Classification of Spices
The turbulent world of plant taxonomy needs to be touched on briefly – and we need to do this to understand where spices come from.
The largest group of plants is the Angiosperms, the flowering plants, which first appeared in the Cretaceous period (c.
145 to 65 million years ago) and then spread extremely quickly. Most of the plants from which spices are derived, with a couple of exceptions, belong to the Angiosperms. It is certainly very interesting to see how spices group together within that large division (there are a total of 64 Orders and 416 Families of flowering plants in the latest APG IV classification). Table 1 on page 14 shows the broad relationship between ninety-six more or less well-known spice plants. Of the thirty-nine families illustrated, three are of particular interest; the Piperaceae (peppers), Apiaceae (coriander/parsley) and Zingiberaceae (ginger) families each contain many different spices (only the ten most important are shown in the table). While this is of general interest in the context of popular spices, it may not amount to much in the wider sense in that there are likely very large numbers of plant species that might be considered ‘spices’ that occupy many different taxa. For example, just the Lamiaceae (mint family) contains around 7,000 species including numerous popular herbs and aromatic plants; the Asteraceae have over 30,000 species.The quandary of which spices to include and which to leave out reaches a head in this chapter. Spices have already been defined, so ostensibly this should be relatively straightforward. But consider the Piperaceae family: it encompasses approximately 3,600 species, ‘approximately’ because new species are frequently found, others may be disputed, and so on. Furthermore, most of those species occur within the Piper genus. Also, should I include obscure species that may be used as a seasoning by an indigenous population dwelling in the rainforest, or restrict the species to the economically important ones? (Answer: I hedged and focused on the most important ones but also included mention of some lesser-known types.) What about species used for traditional medicines (of which there are many)? Many of the well-known spices used today were initially used as medicines by the ancient Greeks and later, before being adapted for use in the kitchen.
I’ve covered both, but with an emphasis on culinary. Some spices have close relatives that are not pungent or aromatic – should they be included? Well, no, not really: I have omitted celeriac (definitely a vegetable), which is a variety of celery (vegetable and herb, and the seeds are a spice) and this has been included. Herbs themselves should also be considered – ‘herb’ is another imprecise catch-all term generally meaning small, non-woody, aromatic plants with culinary or medicinal uses that die back in the winter. Herbs and herbal remedies are referred to in numerous instances in the book, even though this is not the main focus. How about Piper methysticum, the root of which is used to make the well-known stimulant drink ‘kava kava’ of the Pacific Islands? (It’s not strictly a spice, though it does have a certain pungency, but I’ve included it for its interesting and unusual nature.) Other questions lingered around spices used as food colourings, vegetables such as garlic and mustard (pungent seasonings), pomegranate seeds (a spice in Indian cuisine); all were included. Conversely, chia, flax, quinoa, pine nuts, etc., were excluded as they are neither aromatic nor pungent.The geographic distribution of native species (i.e. those that have not been introduced through the intervention of humans) is also very interesting, though there is usually significant uncertainty regarding their precise geographic origin. When fifty-five of the better-known spice plants are plotted on a map in their approximate native position, the distribution is complex (Figure 1). But concentrating on two important botanic families only, then two clear geographic groupings appear: one in the Mediterranean–Middle East area, dominated by the Apiaceae, and the other in south and Southeast Asia, dominated by the Zingiberaceae (Figure 2). Latitude appears to be important – one group is largely temperate and the other largely tropical. The distribution of native species is a snapshot of the relatively recent historic past, i.e.
a few thousand years BCE and in most cases bears little relation to the distribution in the distant geologic past.To look further back into that geologic past can at first be somewhat daunting and confusing. There are fossil records of tropical plants now situated in distinctly temperate climates and vice versa, i.e. temperate plant fossils now situated in tropical settings. The key to understanding this state of affairs is the realisation that the continents themselves are not fixed but have moved vast distances across the earth over geologic time by the process of continental drift.
At the start of the Mesozoic era, a little over 250 million years ago, the world was dominated by a single super-continent, named Pangaea. In fact, this continent had already been in existence for about 100 million years at that point in geologic time. Pangaea later split into two large continents, the northern Laurasia and the southern Gondwanaland (see the maps on p. 17).
The Apiaceae family appears to have originated in the Australasia region in the Late Cretaceous, at around 87 Ma.4 This was after the southern supercontinent Gondwanaland had started breaking up. The Apiaceae spices all belong to the Apioideae subfamily, which seems to have appeared in southern Africa, having made an ancestral jump from Australasia while it was still relatively near. To confuse things even more, the true geographic origins of many commonly known species are only doubtfully known – according to Reduron, this is the case for ajowan, anise, coriander, cumin, dill, fennel and parsley – because they have been used since ancient times, being exchanged, cultivated, etc., and generally moved around, making it impossible to trace them. So-called wild populations may have been plants escaped from cultivation and then naturalised. Could early humans, moving northwards from their origins in East Africa, have helped move these attractive and aromatic fruits with them (by natural ingestion/expulsion)? Possibly, though other animals could also have transported them.
So the location of certain prominent native Apiaceae spices, as shown in Figure 2, needs to be taken with a pinch of salt (if you’ll pardon the expression). However, in broad terms it seems fair to assess their native region, i.e. not long before the domestication of crops, say 9,000–10,000 BCE, as the Med–Middle East–North Africa. Today the Apiaceae have a global distribution, but many of the herbaceous genera seem to belong to this region.With regard to the Zingiberaceae family, we’ll take a closer look at the Indian subcontinent, which certainly punches above its weight considering both the large number of spices that thrive there in the present day and the diversity of native species. The ginger family is native to the region, and yet the parent order, Zingiberales, originated in Gondwanaland at around 124 Ma in the Early Cretaceous period.5 India was part of this southern supercontinent, together with South America, Africa, Antarctica and Australia. Gondwanaland had already started to break up by this time. The Zingiberaceae family split from its close relation the Costaceae at around 105 Ma (the latter became well represented in the Americas), probably before the final break-up of Gondwanaland. The continental fragments were still probably close enough to allow dispersal. India, together with its precious ‘cargo’ of the ginger family, drifted northwards and finally collided with Asia. The Zingiberaceae became highly diversified and dominant in India and Southeast Asia (53 genera/1,200 species). What about Aframoum melegueta (grains of paradise), the ginger family spice that is endemic to West Africa? Well, Africa was also part of Gondwanaland, where the Zingiberaceae originated; however, the genus possibly didn’t diversify until the Pleistocene, around 2.7 million years ago, i.e. very recently in geological terms.6
The Piperaceae are unusual for different reasons: the approximately 3,600 species referred to earlier mostly occur within just two genera: Piper and Peperomia.
The present distribution is pan-tropical with four main centres of origin: the Neotropics (i.e. the tropical parts of the Americas and Caribbean); Southeast and South Asia; Africa; and the Pacific Islands (Figure 3). Molecular dating suggests a Late Cretaceous age for the origin of the two main genera, though it appears that the current species distribution is a result of much later divergence in the Tertiary.7 The genus Piper appears to have originated in the Neotropics before dispersal to the other areas. Radiation/speciation has occurred in the Neotropics, Asia and the Pacific, but the species-poor Africa (there are only two native species of Piper in the entire continent) appears to be the result of much later introductions. The present distribution of spices is completely different yet again because of widespread naturalisation and cultivation by man in suitable and varied ecologic settings.Table 1 | Taxonomy of Some Well-Known Spice Plants
The movement of continents from the Permian period to the present day. Note the separation of the Indian subcontinent from Gondwanaland and northwards movement towards Asia, where collision started around 50 million years ago, causing the uplift of the Himalayas.
However, the importance of this early geographic distribution is that all these groups have clearly influenced regional cuisines, and in some cases from the very earliest days of civilisation. The concomitant effect of this is the extreme pungency of many Asian and Southeast Asian cuisines compared with the milder aromatic cuisines of the Middle East and Mediterranean. Capsicum spp. (chili), however, although widely associated with Asian food today, is native to South America and didn’t reach Asia until the sixteenth century.