albidum overlap but their flowers are very different, so there is little chance of confusion when the plant in question is at flowering stage. On the other hand, the native ranges of T. kurabayashii and T. chloropetalum do not overlap, but in the absence of location data, the two species are often confused since both can (and usually do) have dark purple flowers. To distinguish the two species, the relative length of the stamens is diagnostic: the stamens of T. kurabayashii are about the same length as (or slightly longer than) the carpels, while the stamens of T. chloropetalum are almost twice the length of the carpels. Also, the scape of T. kurabayashii is 2.4–2.6 times as long as the bracts, while the scape of T. chloropetalum is 3.0–3.3 as long as the bracts. Finally, the odor emitted by the flower of T. kurabayashii is spicy and may become fetid with age, whereas the flower odor of T. chloropetalum is pleasantly rose-like. Trillium kurabayashii is distinguished from T. angustipetalum by leaf shape and flower dimensions. The leaves of T. kurabayashii are sessile, usually with acuminate tips, while the leaves of T. angustipetalum have a narrow petiole-like base and tips that are rounded or blunt. On average, the sepals of T. kurabayashii are longer and wider than those of T. angustipetalum. Since the petals of T. angustipetalum are much narrower, the relative dimensions of the petals are dramatically different in each species. The petals of T. kurabayashii and T. angustipetalum have an average length/width ratio of (2.7–) 4.5 (–5.8) and (6.5–) 9.0 (–11.0), respectively. Taxonomy Trillium kurabayashii was one of five new species of sessile-flowered trilliums described by John Daniel Freeman in 1975 (the others being T. albidum, T. decipiens, T. foetidissimum, and T. reliquum). The specific epithet kurabayashii honors Masataka Kurabayashi, a Japanese cytologist and population geneticist whose work first suggested the presence of an unrecognized species of sessile-flowered trillium on the West Coast of the United States. Trillium kurabayashii f. luteum is a synonym for Trillium kurabayashii . This form has yellow or greenish-yellow flowers with little or no purple pigments. It is distinct from the yellow form of Trillium chloropetalum, a taxon whose native range does not overlap with Trillium kurabayashii. Some authorities, including The Jepson Manual, consider Trillium kurabayashii to be a synonym for Trillium angustipetalum . Most other authorities, including the USDA PLANTS Database, Flora of