Primulaceae

Annual or perennial herbs, erect, ascending or prostrate, less than 1½ m high. Leaves spirally arranged or alternate (often various in one plant), or opposite, often in a basal rosette, exstipular, simple, sometimes lobed, penninerved. Inflorescences racemose, terminal (sometimes axillary) racemes or umbels, or flowers in whorls, or solitary axillary. Bracts small or leafy. No bracteoles. Flowers bisexual, actinomorphic (rarely zygomorphic), isomerous, in Mal. always 5-merous, often dimorphous in sexual organs. Calyx dentate or cleft, persistent, sometimes leafy, rarely coloured ( Glaux). Corolla connate, shallowly to deeply cleft (free in Pelletiera), in bud often quincuncial or contorted, variously coloured (absent in Glaux). Stamens inserted on the corolla, epipetalous, rarely alternating With staminodes or their vestiges; anthers dorsifixed or versatile, sometimes basifixed; cells opening with apical pores or latrorse, filaments free or connate. Disk absent. Ovary superior (in Samolus semi-inferior), 1-celled with ~ ovules on a free central placenta; style simple. Capsule mostly 5-valved (valves epi- or alternisepalous) or 10-valved, sometimes irregularly bursting, or circumsciss. Seeds mostly ~, often angular, small; embryo straight, endosperm present; integuments 2. Distribution. Genera 21 with approximately 900 spp., all over the world, but mainly developed in the temperate and cold regions of the northern hemisphere; in the tropics mostly on the mountains. The largest genera, Primula (incl. Androsace) with c. 500 spp. and Lysimachia with c. 150 spp. are almost confined to the northern hemisphere and centre in the Sino-Himalayan region. In Malaysia and Melanesia Primula extends across the equator and finds its southernmost stations in the Old World. Lysimachia and Anagallis have a worldwide area. It is remarkable that the almost cosmopolitan species Samolus valerandi L., which occurs in the surrounding continents of Asia and Australia and is widely distributed in the Pacific (New Caledonia, Loyalty Is., Norfolk I., Chatham, Auckland Is., Kermadec, New Zealand, and Easter I.), has never been found in Malaysia