Pilea
Coll. Bot., plate 4 and text on facing page. 1821, name conserved.
| Taxon | Illustrator ⠉ | |
|---|---|---|
 | Pouzolzia zeylanica Pilea microphylla Parietaria floridana Parietaria pensylvanica Pilea pumila | John Myers John Myers John Myers John Myers John Myers |
Herbs, shrubs, or subshrubs, annual or perennial, glabrous. Stems simple or branched, erect, ascending, or repent. Leaves opposite; stipules present. Leaf-blades paired, equal or unequal, ovate, margins dentate or entire; cystoliths linear, ± conspicuous. Inflorescences axillary, compact to lax cymes. Flowers unisexual, staminate and pistillate flowers in same cyme; bracts deltate to linear. Staminate flowers: tepals 4; stamens 4; pistillode conic. Pistillate flowers: tepals 3, equal or sometimes 1 tepal enlarged and hoodlike; staminodes 3, opposite tepals, under tension and ejecting mature achene; style and tufted stigma deciduous. Achenes sessile, laterally compressed, ovoid to teardrop-shaped, free from perianth at maturity, partly covered by hoodlike tepal. x = 12, 13.
Distribution
Mostly tropical and subtropical regions worldwide except Australia and New Zealand
Discussion
Species ca. 400 (5 in the flora).
Pilea should be further revised.
Selected References
None.
Lower Taxa
Key
| 1 | Leaf margins dentate; paired blades equal. | > 2 |
| 1 | Leaf margins entire; paired blades unequal. | > 3 |
| 2 | Achenes uniformly black except for very narrow, pale, marginal band, surface conspicuously pebbled with raised bosses. | Pilea fontana |
| 2 | Achenes uniformly light colored or streaked with purple, surface smooth or purple striations sometimes slightly raised. | Pilea pumila |
| 3 | Stems repent or prostrate. | > 3 |
| 3 | Stems erect or diffusely ascending. | > 4 |
| 4 | Herbs; leaf blades spatulate to obovate. | Pilea microphylla |
| 4 | Shrubs or subshrubs; leaf blades of 2 types, obovate and orbiculate to orbiculate-cordate. | Pilea trianthemoides |