Pilea

Pilea
	Pilea rotundinucula
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Rosales
Family:	Urticaceae
Tribe:	Elatostemateae
Genus:	Pilea; Lindl., 1821
Species
	See text

Pilea, with 600–715 species, is the largest genus of flowering plants in the nettle family Urticaceae.

It is distributed throughout the tropics, subtropics, and warm temperate regions (with the exception of Australia and New Zealand).

Description

The majority of species are shade-loving herbaceous plants or shrubs, which are easily distinguished from other Urticaceae by the combination of opposite leaves (with rare exceptions) with a single ligulate intrapetiolar stipule in each leaf axil and cymose or paniculate inflorescences (again with rare exceptions).

Uses

Pilea is of little economic importance; one species is used in Chinese traditional medicine (P. plataniflora).^{[citation needed]}

Horticulture

Six species have horticultural value (P. cadierei, P. grandifolia, P. involucrata, P. microphylla, P. nummulariifolia, and P. peperomioides),^[1] Some pileas are grown for their ornamental foliage which is shaped like lily-pads.^[2]

The ASPCA includes many pilea species in the list of plants that are non-toxic to pets.^[3]

Systematics

The genus has attracted little monographic attention since Weddell (1869), and the majority of taxonomic contributions have come from floristic treatments. To date, 787 species names have been published (International Plant Names Index, 2003) and estimates for the species number range from 250 to 1000.^[4] Based on previous floristic treatments, about 30% of the species from regions not yet covered by contemporary floristic treatments may be undescribed.

The genus name Pilea is Latin for "felt cap", a reference to the calyx covering the achene.^[5]

Selected species

Pilea cadierei — aluminium plant
Pilea cataractae
Pilea cavernicola
Pilea crassifolia
Pilea depressa
Pilea elegans
Pilea fontana
Pilea glaucophylla
Pilea grandifolia
Pilea involucrata — friendship plant
Pilea jamesonia
Pilea laevicaulis
Pilea microphylla — artillery plant, gunpowder plant
Pilea mollis — Moon Valley plant
Pilea myriophylla
Pilea napoana
Pilea nummulariifolia — creeping Charlie
Pilea peperomioides — Chinese money plant, missionary plant
Pilea pollicaris
Pilea pumila — Canadian clearweed
Pilea repens — black-leaf panamiga
Pilea riopalenquensis
Pilea schimpfii
Pilea selbyanorum
Pilea serpyllacea
Pilea serratifolia
Pilea spruceana
Pilea topensis
Pilea trianthemoides
Pilea trichosanthes
Pilea trilobata
Pilea tungurahuae
Pilea victoriae

Fossil record

The fossil species †Pilea cantalensis was widely distributed in Europe and West Siberia during the Miocene and Pliocene. It is related to the East Asian Pilea mongolica and to the North American Pilea pumila.^[6]

References

^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 978-1405332965.
^ Peerless, Veronica (2017). How Not to Kill Your Houseplant. DK Penguin Random House. pp. 108–109.
^ "Toxic and Non-Toxic Plant List - Cats". Retrieved 17 April 2021.
^ (C. D. Adams, BM, personal communication).
^ "Pilea in Flora of North America @". Efloras.org. Retrieved 2022-05-01.
^ Łańcucka-Środoniowa M.: Macroscopic plant remains from the freshwater Miocene of the Nowy Sącz Basin (West Carpathians, Poland) [Szczątki makroskopowe roślin z miocenu słodkowodnego Kotliny Sądeckiej (Karpaty Zachodnie, Polska)]. Acta Palaeobotanica 1979 20 (1): 3-117.

Britton, N.L.; Brown, A. (1913). An Illustrated Flora of the Northern United States and Canada. Dover. pp. 634. ISBN 978-0-486-22642-2.
Fouler Rhoads, A.; Block, T.A. (2000). The Plants of Pennsylvania. University of Pennsylvania Press. p. 694. ISBN 978-0-8122-3535-7.
Hortus Third, pages 872-873
Monro 2006
Monro, A.K. (2009). "A new species of Pilea(Urticaceae) from the Talamanca Mountains, Costa Rica". Phytotaxa. 2: 24–28. doi:10.11646/phytotaxa.2.1.4.
Strausbaugh, P.D.; Core, E.L. (1964). Flora of West Virginia (2nd ed.). Seneca Books. pp. 318–9. ISBN 978-0-89092-010-7.
Weddell, H.A. (1869). "Pilea". In De Candolle, A. (ed.). Prodromus systematis naturalis regni vegetabilis. Vol. 16. Paris: Victoris Masson. pp. 104–163.
USDA U.S. Dept. of Agriculture Plants Database