Cyperus esculentus L. - Cyperaceae - earth almond, chufa, tigernut, water grass, yellow nut grass, choufa (fr.), Erdmandel, Tigernuss, Chufa

Perennial, culms solitary, up to 40 cm tall. The spherical tubers are edible have a sweet nutty, almond-like flavor (hence the name) and could be consumed fresh, dried, as a starch source, and roasted. Fresh tubers are fermented to produce alcoholic drinks (African countries) as well as the non-alcoholic Spanish „horchata de chufa“.

„Cyperus esculentus can be found wild, as a weed, or as a crop. Evidence exists for its cultivation in Egypt since the sixth millennium BC, and for several centuries in Southern Europe. In Spain, C. esculentus is cultivated for its edible tubers, called earth almonds or tiger nuts, for the preparation of horchata de chufa, a sweet, milk-like beverage. However, in most other countries, C. esculentus is considered a weed.“
https://en.wikipedia.org/wiki/Cyperus_esculentus

Volatiles of oil from roasted chufa tubers are characterized by high amounts of acetic acid (23.2%), hexanal (14.4%), furfural (4.1%), gamma-butyrolactone (2.5%), and pyrazine derivatives like dimethylpyrazines (5.3%) and 2-methylpyrazine (1.4%). The almond-like flavor can be associated with the high amount of benzaldehyde (1.4%).
[Bail, Stefanie, et al. „Characterization of volatile compounds and triacylglycerol profiles of nut oils using SPME‐GC‐MS and MALDI‐TOF‐MS.“ European journal of lipid science and technology 111.2 (2009): 170-182]

Cyperus esculentus: Sturm, J., Sturm, J.W., Deutschlands Flora, vol.13 t.22 (1828-1830)
http://botanicalillustrations.org/species.php?id_species=309211