TUMAMOCA, A NEW GENUS OF CUCURBITACEAE. 
By J. N. Rose. 
For several years Dr. D. T. MacDougal has been sending to the 
National Museum specimens of a curious little cucurbit which grew 
up over the low bushes about the Desert Laboratory at Tucson, 
Arizona. In 1909 I saw it myself and obtained some roots, which, 
however, failed to grow. It resembled somewhat a delicate Iber- 
villea but seemed different from all the described species. In the 
fall of 1910 Doctor MacDougal sent me fruit, and I was then convinced 
that it is generically distinct from all the species of [bervillea. 
Tumamoca Rose, gen. nov. 
Flowers moncecious; male flowers in few-flowered racemes; calyx with very slender 
tube and 5 small sepals; corolla pale yellow with narrow, elongated lobes; stamens 3, 
borne on the tube about one-fourth the distance below the mouth; 2 of the anthers 
2-celled, the third 1-celled; female flowers axillary, solitary, without stamens; fruits 
globular, several-seeded ; seeds horizontal, black, obovoid, truncate at apex, roughened, 
not marginate. 
This genus differs from Ibervillea in having moncecious flowers and a very slender 
calyx tube upon which the stamens are borne. The seeds, too, are unlike those of 
Ibervillea in shape and marking, while it always produces a cluster of tuberous roots 
instead of a single globular root. 
The nameis from ‘‘Tumamoc,” the Indian name of the hill upon which is located the 
Desert Laboratory of the Carnegie Institution. 
Tumamoca macdougalii Rose, sp. nov. PLATE 17. 
A delicate vine climbing over shrubs; stems annual, arising from a cluster of shallow 
tuberous roots, low, glabrous throughout; leaf blade thin, 3-parted, the lobes usually 
once, rarely twice parted, the ultimate segment narrow, obtuse; male flowers in 2 to 
6-flowered racemes (6 to 10 cm. long); female flowers pale yellow, solitary on peduncles 
5 to 15 mm. long; calyx lobes narrow, 10 mm. long; petals 8 to 12 mm. long; fruit 
globular, red, rarely yellow, 8 to 10 mm. in diameter. 
Type in the U. 8. National Herbarium, no. 591589, collected near the Desert Labora- 
tory, Tucson, Arizona, July 31, 1908, by Dr. D. T. MacDougal. 
EXPLANATION OF PLATE 17.—a, Cluster of roots; b, fruiting branch; c, flower; d, fruit with old flower; 
e, seed; f, longitudinal section of seed; g, cross section of seed. a, 6, Natural size; c-g, enlarged. 
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