Tumamoca Rose, Contr. U.S. Natl. Herb. 16: 21. 1912.
Type: Tumamoca macdougalii Rose, MacDougal s.n. (US-591589), United States, Arizona, Tucson, collected near the Desert Laboratory. 1908.
Perennial climber or trailer with herbaceous to woody shoots, tuberous roots and monoecious sex system. The leaves are simple, petiolate, with pedately trilobed blade, the lobes 2-4 cm long, divided into narrow, obtuse segments. The tendrils are simple and short. The small flowers open at night. Male flowers are produced in racemes, the female flowers stand solitary. The receptacle-tube is elongate, narrowly cylindrical, c. 1 cm long with five triangular, minute sepals. The corolla is rotate with five narrowly linear, pale yellow, 4-6 mm long petals. The three stamens are inserted in the upper half of the tube. Two anthers are bithecous, one monothecous. The ovary is globose to fusiform with many, horizontal ovules. The fruit is a globose berry, c. 1 cm in diam., glabrous, with remains of flower, ripening red (rarely yellow). The two to several seeds are obovoid, 7-8 mm long, truncate at the apex with black, tuberculate-rugose testa.
The two species are extremely rare in semi-desert and xeric bushland in Arizona (near Tucson) and Mexico (Sonora).
The genus is sister to Ibervillea and both are placed in tribe Coniandreae (Schaefer et al. 2009, Schaefer & Renner 2011).
Tumamoca macdougalii Rose, Contr. U.S. Natl. Herb. 16: 21. 1912.
Tumamoca mucronata Kearns, Madroño 41: 27-29. 1994.
Kearns, D. M. 1994. A revision of Tumamoca (Cucurbitaceae). Madroño 41: 23-29.
Khunwasi, C. 1998. Palynology of the Cucurbitaceae. Doctoral Dissertation Naturwiss. Fak., University of Innsbruck.
Schaefer, H. and S.S. Renner. 2011. Phylogenetic relationships in the order Cucurbitales and a new classification of the gourd family (Cucurbitaceae). Taxon 60: 122-138.
Schaefer, H., Heibl, C., and S.S. Renner. 2009. Gourds afloat: a dated phylogeny reveals an Asian origin of the gourd family (Cucurbitaceae) and numerous oversea dispersal events. Proceedings of the Royal Society B 276: 843-851.