1	"Plants with irritant hairs, sometimes sparse"	2
1	"Plants without irritant hairs"	4
2	"Trees; leaves alternate"	Dendrocnide
2	"Herbs; leaves opposite or alternate"	3
3	"Leaves opposite"	Urtica
3	"Leaves alternate"	"Laportea {Laportea interrupta}"
4	"Climbers, vines or lianes"	"Nothocnide {Nothocnide repanda}"
4	"Herbs, sometimes creeping, sometimes epiphytic, or shrubs or trees"	5
5	"Herbs, sometimes creeping; stem often woody at base"	6
5	"Subshrubs, shrubs or trees"	11
6	"Male perianth bilabiate; stamen 1; pistillode absent"	"Australina {Australina pusilla}"
6	"Male perianth 3-5-lobed; stamens 3-5; pistillode small, usually present"	7
7	"Female perianth 2-4-partite"	8
7	"Female perianth tubular, the orifice 2-5-dentate"	9
8	"Leaves usually alternate, falcate or asymmetric  at base"	Elatostema
8	"Leaves opposite, usually symmetric"	"Pilea {Pilea microphylla}"
9	"Flowers solitary, axillary, subtended by an involucre of 1 bract and 2 bracteoles"	"Soleirolia {Soleirolia soleirolii}"
9	"Flowers in clusters of 3 or more"	10
10	"Stipules present at least in young shoots; flowers unisexual; stigma filiform, unilaterally stigmatic; achenes black, smooth, shiny"	Pouzolzia
10	"Stipules absent; flowers unisexual and bisexual; stigma sessile to long-styled, subcapitate to capitate with long stigmatic processes; achenes brown, smooth, shiny"	Parietaria
11	"Female perianth of 3 or 4 (rarely 5) tepals; leaves opposite, 1 of each pair greatly reduced or some aborted so as to appear alternate; male inflorescence a loose cyme; female inflorescence capitate-globose, sessile to subsessile"	"Procris {Procris pedunculata}"
11	"Female perianth tubular, free or adnate to ovary; leaves opposite with 1 of each pair greatly reduced, alternate, or spiralled"	12
12	"Leaves peltate, radially lobed; inflorescence a digitate cluster of spikes inclosed in a spathe"	"Cecropia {Cecropia peltata}"
12	"Leaves not peltate or strongly lobed; inflorescence not as above"	13
13	"Stipules entire; stigma persistent or caducous; female perianth tubular, 2-4-dentate"	14
13	"Stipules bifid; stigma caducous; female perianth minutely dentate"	15
14	"Achene dull, remaining enclosed in fruiting perianth; inflorescence spike-like or paniculate"	Boehmeria
14	"Achene shining, easily detachable from fruiting perianth; inflorescence a sessile axillary cluster"	Pouzolzia
15	"Plants dioecious; inflorescence spicate with flowers clustered into globular heads, forming a multiple fruit; stigma filiform"	"Pipturus {Pipturus argenteus}"
15	"Plants monoecious; inflorescence a short cyme; stigma penicillate"	"Debregeasia {Debregeasia australis}"