Peperomia

Peperomias vary considerably in appearance (see gallery below) and there is no universally accepted method of categorising them, although three main groups can be distinguished. The third group contains geophytic peperomias. These plants have leaves that fall off in the colder dry season, survive due to their underground tubers, and grow the leaves back as more rain falls. Examples include P. macrorhiza, P. peruviana, and P. umbilicata. Currently just under 50 species of geophytic peperomias are known, but new ones continue to be discovered. Peperomia flowers are typically unnoticeable, growing in cordlike spikes, although there are some exceptions such as P. fraseri. Most peperomia flowers seem odorless to humans but some carry a musty or even unpleasant odor, such as P. graveolens. The fruit is a berry that eventually dries out and shows the tiny pepper-like seed. ==Species==

There are over a thousand Peperomia species, although the exact number is unclear as some plants have been recorded several times with different names (c. 3,000 names have been used in publications) and new species continue to be discovered. ==Distribution==

Peperomias are found in tropical and sub-tropical regions around the world. Northern South America and Central America host the largest number of species, but peperomias can also be found in Africa, southern Asia, and Oceania. The exact number of peperomia species continues to change as new plants are discovered and some distinct plant names, perhaps catalogued in separate geographical regions, are realised to describe the same species. Therefore, the table below gives only a rough overall impression of the worldwide distribution. Note that many peperomias are found in wide overlapping regions, for example everywhere in tropical America or Asia, and so may have not been included in the species count for individual areas. ==Peperomias and humans==

Horticulture Peperomias are often grown for their ornamental foliage and many species are considered easy to grow in homes and greenhouses. Several species have been given the Award of Garden Merit by the Royal Horticultural Society. Peperomias are considered non-toxic and are recommended for households with children or animals. Out of the 1,000+ Peperomia species, currently only about 40 of them are commonly used as houseplants. These peperomias fare well in average home conditions and can relatively easily be found in stores and garden centers. Species in this basic group include P. alata, P. albovittata, P. argyreia, P. blanda, P. boivinii, P. caperata, P. clusiifolia, P. columella, P. dolabriformis, P. ferreyrae, P. fraseri, P. glabella, P. graveolens, P. griseoargentea, P. hoffmannii, P. incana, P. japonica, P. kimnachii, P. maculosa, P. metallica, P. nitida (often sold as P. scandens), P. nivalis, P. obtusifolia, P. pellucida, P. perciliata, P. pereskiifolia, P. polybotrya, P. prostrata, P. quadrangularis (syn. P. angulata), P. rotundifolia, P. rugosa, P. tetragona (syn. P. puteolata), P. tetraphylla, P. turboensis, P. urocarpa, P. verschaffeltii, P. verticillata (syn. P. rubella), and P. wheeleri. There can be, however, several cultivars available from each species. Identifying species can be challenging as plants are often sold under marketing names, older synonyms, or under names that have not been officially accepted. This is the case, for example, with Peperomia orba (often sold as Peperomia 'Pixie'), Peperomia viridis, and Peperomia axillaris. In addition to natural species and their cultivars, some artificial hybrid varieties can also be found on the market, such as Peperomia 'Hope' (a cross between P. deppeana and P. quadrifolia). Most species need airy, well-draining substrate and want to dry out to some extent or even completely between waterings. A typical reason for losing a peperomia is through root rot caused by over-watering. Some species, including Peperomia inaequalifolia, Peperomia congona and Peperomia pellucida, are also used in herbal medicine for various health conditions. While such folk medicine usage is common in Peru and elsewhere, the possible medicinal qualities of peperomias remain poorly investigated, although there has been a growing interest for the subject recently. ==Propagation==

These plants can be propagated by seeds, by cuttings, or by dividing. Peperomia cuttings of many species root easily. Cuttings should be taken in spring or summer, with the lower leaves removed and a cut made just below a node. The cuttings are left to dry for about an hour to allow a protective callus tissue to form, preventing rot. Once dried, they can be planted in a well-draining substrate such as perlite or peat moss. Semi-succulent species benefit from bottom heat around 21–24°C (70–75°F), but it is important not to seal the top completely, as excessive humidity can be detrimental. Once roots have formed, the cuttings can be transplanted into 75 mm (3 in) pots or hanging baskets. Peperomia plants can also be propagated by division, especially clumping species. Division involves separating the plant into smaller sections, each with roots attached, and is best done during repotting in the growing season. Seed propagation is less common due to slower germination but can be achieved by sowing seeds in a well-draining, sterile medium while maintaining warm, humid conditions. Maintaining warm temperatures (18–24°C) and moderate humidity is essential for successful propagation. Overwatering should be avoided, as Peperomias are prone to root rot in poorly draining soils. ==Gallery==

Examples of tropical, decorative foliage types Image:Peperomia argyreia.jpg|Peperomia argyreia, "watermelon peperomia" Image:Peperomia griseoargentea.jpg|Peperomia griseoargentea Image:Peperomia nitida 'Variegata'.jpg|Peperomia nitida "variegata" Image:Peperomia maculosa kz3.jpg|Peperomia maculosa Image:Inflorescence_Peperomia_obtusifolia.JPG|Peperomia obtusifolia leaf and flower spike Image:Peperomia prostrata.jpg|Peperomia prostrata, "string of turtles" Image:Peperomia rotundifolia var. rotundifolia kz02.jpg|Peperomia rotundifolia growing on a tree Image:Peperomia serpens 2011-01-17.jpg|Peperomia serpens Image:Peperomia tetraphylla00.jpg|Peperomia tetraphylla with flower spike Examples of arid climate succulent types Image:Peperomia columella 01.jpg|Peperomia columella Image:Peperomia dolabriformis.jpg|Peperomia dolabriformis Image:Peperomia graveolens - Botanischer Garten Bonn.jpg|Peperomia graveolens Image:Peperomia nivalis crassa.jpg|Peperomia nivalis Examples of geophytic peperomias Image:Peperomia bracteata.jpg|Peperomia bracteata Image:Peperomia monticola.jpg|Peperomia monticola ==See also==