Spermacoceae

Salas, Roberto M., Viana, Pedro L., Cabral, Elsa L., Dessein, Steven & Janssens, Steven, 2015, Carajasia (Rubiaceae), a new and endangered genus from Carajás mountain range, Pará, Brazil, Phytotaxa 206 (1), pp. 14-29 : 20-21

Key to taxa with deeply divided stigma of Spermacoceae s.s.

1 Inflorescence lax, thyrsoid or pleiothyrsoid; flowers pedicellate.......................................................................................................2

- Inflorescence mostly congested; sometimes thyrsoid or dichasial, and with sessile or subsessile flowers......................................4

2 Fruit 4-carpellate; mericarps indehiscent ..................................................................................................................... Schwendenera

- Fruit 2-carpellate; mericarps dehiscent..............................................................................................................................................3

3 Inflorescence umbellate, flowers homostylous; fruit with an apical extension of the carpel, longer than the length of the calyx lobes; seed strophiole longer than the seed length ........................................................................................................... Emmeorhiza

- Inflorescences thyrsoid, flowers heterostylous; fruit without an apical extension of the carpel; seed strophiole equal or shorter than the seed length ....................................................................................................................................... Galianthe subgen. Galianthe

4 Fruit indehiscent, dry or fleshy...........................................................................................................................................................5

- Fruit completely or partially separated into 2–4 dry mericarps when mature....................................................................................7

5 Herbs prostrate, rooting at the nodes; flowers homostylous, corolla tube filiform, internally glabrous................................... Diodia

- Subshrubs or small shrubs, erect, without roots at the nodes; flowers heterostylous, corolla tube funnel-shaped, internally with a fringe of moniliform hairs..................................................................................................................................................................6

6 Plants without fetid smell; leaf blades linear or narrowly elliptic, 5–10 × 0.3 mm, coriaceous when dry; corolla 4–4.5 mm long; drupe reddish-yellow ............................................................................................................................................................. Tortuella

- Plants with fetid smell; leaf blades ovate or elliptic, 40–110 × 25–30 mm long, papery when dry; corolla 1.5–2 mm long; capsule brown-colored......................................................................................................................................................................... Tobagoa

7 Ovary (2-) 3- or 4-carpellate; calyx lobes deciduous at fruit maturity ................................................................................. Richardia

- Ovary 2-carpellate; calyx lobes persistent on the fruit.......................................................................................................................8

8 Herbs rupicolous, with stems and leaves reddish; inflorescences heads axillary, 1-flowered; calyx lobes 0.15–0.17 mm long; corolla 1–1.2 mm long; style pubescent; nectariferous disc with scattered hairs ................................................................ Carajasia

- Herbs or subshrubs, generally psammophilous, rarely rupicolous, with green stems and leaves, sometimes with reddish leaf margins; inflorescences heads terminal and axillary, mostly many-flowered; calyx lobes 0.5–10 mm long; corolla 2–15 mm long; style glabrous; nectariferous disc with glands....................................................................................................................................9

9 Fruit with longitudinal dehiscence; calyx 4-lobed, lobes equal in size............................................................................................10

- Fruit with circumscissile or longitudinal-oblique dehiscence; calyx 2- or 4-lobed, when 4-lobed then with 2 lobes visibly smaller than the other 2.................................................................................................................................................................................12

10 Mericarps indehiscent; inflorescences thyrsoid or dichasial with partial inflorescences congested........... Galianthe subgen. Ebelia

- Mericarps dehiscent; inflorescences partial inflorescences in glomerules.......................................................................................11

11 Flowers heterostylous; fruit with intercarpelar septum persistent on the pedicel and mericarps caducous, strongly compressed parallel to the septum ........................................................................................................................... Psyllocarpus sect. Amazonica

- Flowers homostylous; fruit with septum and mericarps persistent on the pedicel, without compression, commonly obovoid .......... ................................................................................................................................................................. Borreria subsect. Latifoliae

12 Calyx lobes with 2 larger and 2 smaller lobes; fruits with circumscissile dehiscence; mature anthers usually yellow, rarely blackish ..................................................................................................................................................................... Mitracarpus

- Calyx lobes equal or subequal; fruits with longitudinal-oblique dehiscence in both carpels; mature anthers blue, creamy or whitish ............................................................................................................................................................................... Staelia