Urophyllum, Wall.

Yooprasert, Sawita, Culham, Alastair, Tagane, Shuichiro, Yahara, Tetsukazu, Nguyen, Van Du, Nguyen, Khang Sinh & Utteridge, Timothy M. A., 2022, New species and new status of Urophyllum Wall. (Rubiaceae) from Cambodia and Viêtnam, Adansonia (3) 44 (11), pp. 91-114 : 94

KEY TO UROPHYLLUM WALL . SPECIES IN CAMBODIA, LAOS AND VIÊTNAM

1. Stipule glabrous to subglabrous abaxially, sparse hairs present at margin and dense at base adaxially or only at apex abaxially, sometimes hairy only along midline; netted veins conspicuous in sicco ................................. 2

— Stipule hairy abaxially throughout; netted veins inconspicuous in sicco .......................................................... 4

2. Petiole glabrous to the naked eye; inflorescence pedunculate umbellate; Viêtnam ........................................ 3

— Petiole hairy to the naked eye on canalicular ridges; inflorescence sessile umbellate; Cambodia ...................... ............................................................ Urophyllum pulchristipulum Yooprasert, Culham & Utteridge , sp. nov.

3. Stipule glabrous to subglabrous with hairs only at the apex ............................................................................ ................................................................... Urophyllum bidoupense Yooprasert, Culham & Utteridge , sp. nov.

— Stipule hairy along the midline from base to apex .......................................................................................... ........................ Urophyllum chinense subsp. latistipulum Yooprasert, Culham, Yahara & Utteridge , subsp. nov.

4. Petiole hairs conspicuously denser on canalicular ridges, sometimes hairy only on the ridges ....................... 5

— Petiole hairs similar density all over ............................................................................................................... 7

5. Stipule margin with hairs denser than other areas; petiole hairy throughout, but with hairs along canalicular ridges distinctly paler and contrasting ........................................ Urophyllum parviflorum F.C.How ex H.S.Lo

Stipule hair density similar throughout; petioles variously hairy, but hairs the same colour throughout and without any contrasting colours .................................................................................................................. 6

6. Staminate inflorescence sessile umbellate; staminodes absent in pistillate flowers; Viêtnam ............................. ................................... Urophyllum pseudoschmidtii Yooprasert, Culham, Yahara, Tagane & Utteridge , sp. nov.

Staminate inflorescence pedunculate umbellate; staminodes present in pistillate flowers; Thailand and Cambodia................................................................................................................. Urophyllum schmidtii C.B.Clarke

7. Secondary veins weakly brochidodromous (loops inconspicuous) or eucamptodromous .............................. 8

Secondary veins conspicuously brochidodromous or festooned brochidodromous ..................................... 10

8. All parts covered with long sericeous hairs; corolla with sparse sericeous hairs abaxially .................................. ............................................................................................................................... Urophyllum argenteum Pit.

All parts subglabrous or covered with hairs but not sericeous; corolla glabrous abaxially .............................. 9

9. Leaves coriaceous, abaxial lamina densely appressed hairy; stipules appressed to the stem, sometimes recurved at margins but not folded; inflorescence single flower or pedunculate umbellate, small number of flowers usually <5; corolla white ............................................................ Urophyllum chinense subsp. chinense Merr. & Chun

Leaves chartaceous, abaxial lamina glabrous; stipule folded toward adaxial side; inflorescence compound cymose, many flowers> 7; corolla green ...................................................................................................................... .......................................... Urophyllum annamense (Pierre ex Pit.) Yooprasert, Culham & Utteridge , stat. nov.

10. Adaxial leaf veins glabrous; leaf reddish brown in sicco; tertiary veins not prominent, inconspicuous abaxially; inflorescence peduncle long 5-10 mm, sparsely hairy; abaxial corolla surface glabrous.............................. ....................................................................................................... Urophyllum tsaianum F.C.How ex H.S.Lo

Adaxial leaf veins hairy, sometimes only on midrib; leaf yellowish or greenish brown to dark grey in sicco; tertiary veins prominent, conspicuous abaxially; inflorescence peduncle short or sessile 0-2.9 mm, densely hairy; abaxial corolla surface hairy .................................................................................................................................. 11

11. Mature leaves with secondary veins hairy adaxially, brochidodromous without a series of small loops outside the main loop or inconspicuous; flower and fruit calyx lobes recurved ............................................................ .......................................................... Urophyllum brochidodromum Yooprasert, Culham & Utteridge , sp. nov.

Mature leaves with secondary veins glabrous, brochidodromous with a series of small loops (festooned); flower and fruit calyx lobes erect or folded toward adaxial side ............................................................................. 12

12. Pistillate plant with pedunculate umbellate inflorescence .......................................... Urophyllum lecomtei Pit.

Pistillate plant with sessile umbellate inflorescence ................................................ Urophyllum tonkinense Pit.