Psidium Linnaeus 1753

Key distinguishing Psidium and Mosiera

1. Flowers tetramerous, the calyx with 4 distinct lobes; seed coat smooth, lustrous with surface cells forming a mosaic pattern, or leathery-verrucose, 1–6(–10) cells thick; anthers usually with a single terminal gland in the connective; peduncles uniflorous, solitary or borne in pairs at a node on a very short axillary shoot; tertiary veins between lateral veins if visible usually forming a reticulate, web-like pattern ..................................................................................................................................................... Mosiera

1ʹ Flowers pentamerous or tetramerous, the calyx closed in the bud or if open with 5 more or less distinct lobes; seed coat dull to rough, not lustrous, covered with a thin layer of pulpy tissue when wet (or a glaze or crusty layer when dry), the hard portion of the seed coat (5–)8–30 cells thick at narrowest point; anthers with a terminal gland and usually with a few to several glands in the connective below; peduncles uniflorous or sometimes bearing a 3-flowered dichasium, or sometimes borne on bracteate shoots (racemes), but not normally appearing as pairs on very short axillary shoots; tertiary veins between lateral veins when visible forming a ladder-like (e.g., P. guajava Linnaeus (1753: 470) or dendritic pattern [e.g., P. salutare (Kunth 1823: 132) O. Berg (1855 –1856: 356)]................................................................................................................................................................... Psidium

A problematic species, Calycorectes ekmanii Urban (1923: 110, not Mosiera ekmanii (Urb.) Bisse (1985: 4), based on Myrtus ekmanii Urban (1923: 79)), is similar to Mosiera and we believe it to be conspecific with M. nipensis Salywon & Landrum (2014: 275). It has seeds similar to Mosiera, but the 4-lobed calyx lobes are valvate in the bud. Molecular studies (Flickinger et al. 2020) indicate an affinity to Calycolpus O. Berg (1855 –1856: 348).