Bactris is a genus of spiny palms which is native to the Mexico, South and Central America and the Caribbean. Most species are small trees about 2 m (6 ft 7 in) tall, but some are large trees while others are shrubs with subterranean stems. They have simple or pinnately compound leaves and yellow, orange, red or purple-black fruit. The genus is most closely related to several other spiny palms—Acrocomia, Aiphanes, Astrocaryum and Desmoncus. The fruit of several species is edible, most notably B. gasipaes, while others are used medicinally or for construction.
The ancestors of the genus are believed to have entered South America during the late Cretaceous. Bactris shows high rates of speciation.
Both stems and leaves of Bactris species are generally covered with spines. Stems generally bear spines on the internodes; in B. glaucescens and B. setulosa spines are also present on the nodes. A few species lack spines on their stems. All species have spiny leaves; the spines are often clustered on the petiole or rachis. In some species the spines are only found on the tips of the leaflets.[2]:4–5 Most species grow in multi-stemmed clumps with stems about 2 metres (6 ft 7 in) tall and 3 centimetres (1.2 in) in diameter, but they span a range of sizes from tall trees to shrubs with subterranean stems and are sometimes single-stemmed. Stems can be as narrow as 0.3–0.5 centimetres (0.1–0.2 in) in B.aubletiana or as broad as 25 centimetres (10 in) in B. gasipaes.[2]:4
The leaves can be either pinnately compound or simple; in some species like B. hirta both types of leaves exist. Petioles range from 5 centimetres (2.0 in) to over 1.5 metres (4 ft 11 in) in length, while the rachis (which bears the leaflets) can be 3 centimetres (1.2 in) to over 3 metres (9.8 ft) long.[2]:4–5 Inflorescences are borne singly emerging from the leaf axil. Flowers grow in triplets along the inflorescence; each female flower is flanked by two male flowers; elsewhere along the inflorescence male flowers grow singly or in pairs. Ripe fruit can be yellow, orange, red or purple-black (other colours are present in a few species) and range from 0.5–4.5 centimetres (0.2–1.8 in) long.[2]:5–11
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