OLMECA,A NEW GENUS OF MEXICAN BAMBOOS WITH FLESHY FRUITS

Olmeca, a new bamboo genus of two species is described from southern Mexico. It is unique among New World bamboos in its production of fruits that are large and fleshy, in contrast to the smaller, dry type—caryopsis or achene—that characterizes the other genera. The fleshy fruit is found in few other bamboos, among them Dinochloa, Melocanna, and Ochlandra. These Asiatic genera are not all closely related to each other nor to the new American genus, but do share a similar type of habitat: the tropical lowland rain forest, where ample water is available throughout the year. Besides the rare type of fruit found in Olmeca, the rhizomes of this genus develop necks up to 8 m or more long, an uncommon feature among any world bamboo of the sympodial type. The solitary culms of Olmeca grow widely spaced from one another because of these elongated, intervening necks. One species. O. recta, is known only from the mountain range of Los Tuxtlas, in Veracruz, where it grows on acidic soils derived from basalt; the other, O. reflexa, occurs on calcareous soils and has a wider range that encompasses parts of Veracruz, Oaxaca, and Chiapas.