Pitardella species

Chen, Junhao, Ng, Xin Yi & Wong, Khoon Meng, 2024, Two new combinations in Pitardella (Rubiaceae) and first record of the genus in the Malay Peninsula, Phytotaxa 664 (2), pp. 146-150 : 149

Key to Pitardella species

1a. Corolla tube densely patent hairy ................................................................................................................................. P. caudatifolia

1b. Corolla tube densely appressed hairy .................................................................................................................................................2

2a. Inflorescences sessile; calyx teeth subulate ................................................................................................................... P. sikkimensis

2b. Inflorescences distinctly pedunculate; calyx teeth broad- to shallow-triangular ...............................................................................3

3a. Corolla lobes half or more than half the length of the corolla tube..................................................................................... P. poilanei

3b. Corolla lobes less than half the length of the corolla tube .................................................................................................................4

4a. Leaves broadly obovate, 4.5–7 cm wide, lower surface olive-green or olive-brown when dry; bracteoles involucral; calyx lobes broad-triangular .............................................................................................................................................................. P. kelantansis

4b. Leaves lanceolate or oblanceolate, up to 4 cm wide, lower surface with a glaucous appearance when dry; bracteoles discrete, whisker-like; calyx lobes shallow-triangular (length less than half the basal width)............................................... P. mussaendoides