which has large, pinnate leaves. The fruit is unusual in that it floats, and the stem is dichotomously branched, also unusual in palms. Subfamily has small to medium-sized flowers, spirally arranged, with a gynoecium of three joined carpels. The are the largest subfamily, with six diverse tribes (Areceae, Caryoteae, Cocoseae, Geonomateae, Iriarteeae, and Podococceae) containing over 100 genera. All tribes have pinnate or bipinnate leaves and flowers arranged in groups of three, with a central pistillate and two staminate flowers. The are a monoecious subfamily. Members of this group have distinct monopodial flower clusters. Other distinct features include a gynoecium with five to 10 joined carpels, and flowers with more than three parts per whorl. Fruits are multiple-seeded and have multiple parts. Currently, few extensive phylogenetic studies of the Arecaceae exist. In 1997, Baker et al. explored subfamily and tribe relationships using chloroplast DNA from 60 genera from all subfamilies and tribes. The results strongly showed the Calamoideae are monophyletic, and Ceroxyloideae and Coryphoideae are paraphyletic. The relationships of Arecoideae are uncertain, but they are possibly related to the Ceroxyloideae and Phytelephantoideae. Studies have suggested the lack of a fully resolved hypothesis for the relationships within the family is due to a variety of factors, including difficulties in selecting appropriate outgroups, homoplasy in morphological character states, slow rates of molecular evolution important for the use of standard DNA markers, and character polarization. However, hybridization has been observed among Orbignya and Phoenix species, and using chloroplast DNA in cladistic studies may produce inaccurate results due to maternal inheritance of the chloroplast DNA. Chemical and molecular data from non-organelle DNA, for example, could be more effective for studying palm phylogeny. Selected genera Archontophoenix—Bangalow palm Areca—Betel palm Astrocaryum Attalea Bactris—Pupunha Beccariophoenix—Beccariophoenix alfredii Bismarckia—Bismarck palm Borassus—Palmyra palm, sugar palm, toddy palm Butia Calamus—Rattan palm Ceroxylon Cocos—Coconut Coccothrinax Copernicia—Carnauba wax palm Corypha—Gebang palm, Buri palm or Talipot palm Elaeis—Oil palm Euterpe—Cabbage heart palm, açaí palm Hyphaene—Doum palm Jubaea—Chilean wine palm, Coquito palm Latania—Latan palm Licuala Livistona—Cabbage palm Mauritia—Moriche palm Metroxylon—Sago palm Nypa—Nipa palm Parajubaea—Bolivian coconut palms Phoenix—Date palm Pritchardia Raphia—Raffia palm Rhapidophyllum Rhapis Roystonea—Royal palm Sabal—Palmettos Salacca—Salak Syagrus—Queen palm Thrinax Trachycarpus—Windmill palm, Kumaon palm Trithrinax Veitchia—Manila palm, Joannis palm Washingtonia—Fan palm Evolution The Arecaceae are the first modern family of monocots appearing in the fossil record around 80 million years ago (Mya), during the late Cretaceous period. The first modern species, such as Nypa fruticans