The Tropical Turn: Agricultural Innovation in the Ancient Middle East and the Mediterranean. Sureshkumar Muthukumaran. University of California Press, Oakland, CA, USA, 2023, pp. xix + 294. <scp>ISBN</scp> 978‐0‐520‐39084‐3 (pbk).

Sureshkumar Muthukumaran's first book, The Tropical Turn, makes an explicit case for the intercontinental travel of plant species from South Asia to the Mediterranean, long before the year 1492. This year marked the Old World Colonization of the Americas, and its peoples, ‘inaugurat[ing] a world without biological borders’ (p. 1). Like this biological diffusion, coined by Alfred Crosby as The Columbian Exchange (1972), thresholds in agricultural histories are commonly delineated by historians and archaeologists as revolutions or exchanges. Muthukumaran however proposes first, that ‘revolution is a misnomer’ (p. 2), and second, that the ‘transmission of crops and fauna of tropical and subtropical Asian origins from the Indian subcontinent to the Middle East and the Mediterranean’ (p. 4) deserves much greater attention. Muthukumaran's primary argument, which he develops by following seven commodity crops—cotton, rice, citruses, cucurbits, lotuses, taro, and sissoo—is that ‘the growing agro-ecological coherence of Afro-Eurasia in turn abetted processes of cultural coalescence and facilitated the spread of ideas and technologies’ (p. 4). He deftly reads archaeological records through the archaeobotanical, genetic, sensorial, and culinary or tactile uses of these crops which originate in the tropical and subtropical zone between Papua New Guinea and northwestern India. Their diffusion, as the single ‘largest group of introduced aliens in the Middle East and the Mediterranean’ (Zohary, 1998: 127 cited in p. 4), created a ‘unified ecological contact zone’ (Mikhail, 2011: 952 cited in p. 4) of overlapping cultivars and livestock in the southern Eurasian landmass. While historical and archaeological scholarship has ‘attributed agency to specific actors—including the Romans, Sasnian Persians, and the medieval Arabs’ (p. 5), the book shows that crop movement took place with no single protagonist orchestrating or sustaining the process. The methodological sophistication needed to trace these crops makes this clear: a combination of naming conventions across languages, morphological features, and taste—which requires familiarity with food and culinary practices—are knowledge sources equal to archival spaces that take a ‘view from nowhere’. Muthukumaran consults sources in Sumerian, Akkadian, Elamite, Hebrew, Aramaic, Greek, Latin, Sanskrit, and the Prakrits, noting that plants appear as incidental mentions, with little detail on cultivation context and transmission modes (p. 11). Clay tables in the cuneiform script are not privileged due to ‘imprecise identification of ancient plant names with modern botanical equivalents’ which become harder to track as lexical cognates in related languages thin out (p. 11). More substantial Greco-Roman records nonetheless illuminate how ‘not all authors saw the plant being described and some authors plagiarised and garbled older accounts’ (p. 11). Muthukumaran also documents the semantic fluidity across botanical terms—where for instance, ‘malum’ in Latin encompasses ‘apple’ but also ‘fleshy arboreal fruits like peaches, quinces, pomegranates and citruses’ (p. 12). Especially confounding is the curcubit (cucumber, gourd, melon), which materializes with such polymorphic and sematic flexibility (in physical form and linguistic record) that it appears as pépon (melon), sikúa (and its masculine equivalent síkuos), kolokúnthē, in elongate and non-elongate forms, with more or less sweetness, or snake-like, known as faqqūs in Arabic (p. 154–8). Readers may recognize contemporary similarities in Mandarin Chinese (xī kūa) or Thai (fàk—for gourds, including pumpkin, fàk thoong). Muthukumaran's reading matters because the hybridity of morphological forms, which evade tracking in antiquity, persists today. Constant pressure on their growing environments erodes the diversity of their forms, but so too does a one-dimensional reading of their heterogeneity. Weaving other readings into the historiography of plant movements, Muthukumaran shows how it takes, for instance, bodily understanding of these plants to identify and read their particular histories as matter. The unripe síkuos for instance, is described by a Hippocratic author in the fifth/fourth century BCE as having indigestible seeds. This cannot apply to cucumbers and melons, Muthukumaran notes, as these are consumed immature. Other curcubits were defined through their taste: ‘foul’, ‘bitter’, ‘sweet when their seeds are steeped in honeyed milk’ (p. 159). But taste too, has its limits in reading or writing history: ‘[t]he mutability of taste sensations across space and time,… caution against mapping contemporary notions of bitterness and sweetness onto the past’ (p. 159). The book has a numerous, and vibrant selection of quotes—such as cultural historian Andrews’ (1961) critique of Latin writer Solinus—‘such an unobservant individual that he was capable of being oblivious to a citron tree growing in his neighbour's backyard’ (Andrews, 1961: 41 cited in p.12) or the way cotton became a luxury as diaphanous cotton textiles, produced in Bengal, become named śabnam, ‘evening dew’ because it was ‘reputed to become invisible when laid over dewed grass’ (p. 98). This quality, Muthukumaran emphasizes, was perhaps what prompted consumers to ‘attempt its cultivation in spite of environmental and economic impediments’ (p. 98). Thus, desire and appeal, and non-intentionality, equally drove crop migration, which ‘cannot be reduced to subsistence values’ (p. 208). The conclusion then traces four stages of this movement through a diverse set of crop movers: familiarization, experimentation, routinization, and indigenization. Throughout, the book rebuts assumptions relating to crop-environment interactions and cultivation intent. Crop movement occurred not primarily for subsistence: but rather as ‘opportunistic events’ (p. 211). Plants are not passive: ‘thirsty tropical and subtropical crops were adopted in spite of long-term fluctuations in pluviality’, made possible by ‘phenological changes’ they underwent including ‘germination, flowering, seed dispersal and seasonal dormancy’ (p. 214). They eventually fit into a seasonal niche as their cultivation became routinized in the Mediterranean: ‘temporally restricted to summer and spatially restricted to localities that fulfill…requirements [of] the experimentation phase’ (p. 218). This ‘cautions against environmentally deterministic approaches which ignore human and plant adaptability’ (p. 212). Plant movers and cultivators were also not heterogeneous. The book's survey of historical material beyond the archive, enriches recent anthropological revisitings of the role of choice in self-identification and cultural differentiation, in human-plant relations, customary practices, and movement (e.g. Graeber & Wengrow, 2021), with wide interest for geographers, political scientists, anthropologists, sociologists and historians with interests spanning transcontinental food and agricultural mobility, global circuits, decolonial readings of historical actors, and the spaces and places of food production.