displayed remarkable strength under test conditions. Bambusa tulda of Bangladesh and adjoining India has tested as high as 60,000 pounds (27,000 Kg or 27 tonnes) per square inch in tensile strength. Other bamboos have extraordinailly hard wood. Bambusa tabacaria of China contains so much silica that it will make sparks when struck by an axe. Taxonomy Bamboos have long been considered the most primitive grasses, mostly because of the presence of bracteate, indeterminate inflorescences, "pseudospikelets", and flowers with three lodicules, six stamens, and three stigmata. Following more recent molecular phylogenetic research, many tribes and genera of grasses formerly included in the Bambusoideae are now classified in other subfamilies, e.g. the Anomochlooideae, the Puelioideae, and the Ehrhartoideae. The subfamily in its current sense belongs to the BOP clade of grasses, where it is sister to the Pooideae (bluegrasses and relatives). The bamboos comprise three clades classified as tribes, and these strongly correspond with geographic divisions representing the New World herbaceous species (Olyreae), tropical woody bamboos (Bambuseae), and temperate woody bamboos (Arundinarieae). The woody bamboos do not form a monophyletic group; instead, the tropical woody and herbaceous bamboos are sister to the temperate woody bamboos. Altogether, more than 1,400 species are placed in 115 genera. 21 genera: Subtribe Buergersiochloinae one genus: Buergersiochloa. Subtribe Olyrineae 17 genera: Agnesia, Arberella, Cryptochloa, Diandrolyra, Ekmanochloa, Froesiochloa, Lithachne, Maclurolyra, Mniochloa, Olyra, Parodiolyra, Piresiella, Raddia, Raddiella, Rehia, Reitzia (syn. Piresia), Sucrea. Subtribe Parianinae three genera: Eremitis, Pariana, Parianella. 73 genera: Subtribe Arthrostylidiinae: 15 genera: Actinocladum, Alvimia, Arthrostylidium, Athroostachys, Atractantha, Aulonemia, Cambajuva, Colanthelia, Didymogonyx, Elytrostachys, Filgueirasia, Glaziophyton, Merostachys, Myriocladus, Rhipidocladum. Subtribe Bambusinae: 17 genera: Bambusa, Bonia, Cochinchinochloa, Dendrocalamus, Fimbribambusa, Gigantochloa, Maclurochloa, Melocalamus, Neomicrocalamus, Oreobambos, Oxytenanthera, Phuphanochloa, Pseudoxytenanthera, Soejatmia, Thyrsostachys, Vietnamosasa, Yersinochloa. Subtribe Chusqueinae: one genus: Chusquea. Subtribe Dinochloinae: 7 genera: Cyrtochloa, Dinochloa, Mullerochloa, Neololeba, Pinga, Parabambusa, Sphaerobambos. Subtribe Greslaniinae: one genus: Greslania. Subtribe Guaduinae: 5 genera: Apoclada, Eremocaulon, Guadua, Olmeca, Otatea. Subtribe Hickeliinae: 9 genera: Cathariostachys, Decaryochloa, Hickelia, Hitchcockella, Nastus, Perrierbambus, Sirochloa, Sokinochloa, Valiha. Subtribe Holttumochloinae: 3 genera: Holttumochloa, Kinabaluchloa, Nianhochloa. Subtribe Melocanninae: 9 genera: Annamocalamus, Cephalostachyum, Davidsea, Melocanna, Neohouzeaua, Ochlandra, Pseudostachyum, Schizostachyum, Stapletonia. Subtribe Racemobambosinae: 3 genera: Chloothamnus, Racemobambos, Widjajachloa. Subtribe Temburongiinae: one genus: Temburongia. incertae sedis 2 genera: Ruhooglandia, Temochloa. 31 genera: Acidosasa, Ampelocalamus, Arundinaria, Bashania, Bergbambos, Chimonobambusa, Chimonocalamus, Drepanostachyum, Fargesia, Ferrocalamus, Gaoligongshania, Gelidocalamus, Himalayacalamus, Indocalamus, Indosasa, Kuruna, Oldeania, Oligostachyum, Phyllostachys, Pleioblastus, Pseudosasa, Sarocalamus, Sasa, Sasaella, Sasamorpha, Semiarundinaria, Shibataea, Sinobambusa, Thamnocalamus, Vietnamocalamus, Yushania. Distribution Most bamboo species