XCVIII. ACANTHACEiE (bURKTLL AND CLARKE). 



Tribe III, Ruellieee. — Corolla-lohes contorted in the bud {no lobe lohoUy with- 

 out or lohollji loithiti the others). Stamens 4 polliniferous (except in Brillantaisia, 

 Lankesleriaj ; anther-cells at equal heirjht ; pollen of 3 forms, viz. (a) globose, honeij- 

 combed or reticulated; (h) globose, echinulate or nearhj smooth; (c) ellipsoid, with 

 (9-15) narrow longitudinal smooth grooves. Calyx or bracteoles often conspicuous, 

 Seeds {in all but two or three small genera) discoid, covered, at least on margins, with 

 many extremely fine hairs which spring out on applying boater. 



Subtribe i. IIygroi'Hile^. — Ovules 3 or more in each 

 cell ; capsule (unless accidentally) many-seeded. Corolla 

 distinctly 2 -lipped (see also Meltera among the Euruel- 

 liece). 

 Retinacula very small, conical, not curved ; seeds without 



hygroscopic hairs. — Small herbs . . . .5. Synnema. 

 Retinacula curved ; seeds with hygroscopic hairs ; anther- 

 cells muticous ; pollen ellipsoid, ribbed longitudin- 

 ally. 



Stamens 4 6. IIygbophila. 



Stamens 2. Flowers large or medium . . .7. Buillantaisia.. 



Subtribe ii. EuKUELLiEiE. — Ovules 3 or more in each cell ; 

 capsule many-seeded. Corolla not (or indistinctly) 2- 

 Hpped (in Mellera, the anticous lobe of corolla is ovate, 

 twice as broad as the others). 

 Pollen globose ; surface honeycombed or reticulated. 

 (Stamens 4 ; anthers muticous ; inflorescence not 

 strobilate.) 

 Leaves in subequal pairs, subequal at the base . . 8. 

 Leaves in unequal pairs, oblique at the base , . 9. 



Pollen ellipsoid, with 9-15 narrow longitudinal smooth 

 grooves. 

 Flowers large, laxly or closely panicled. Large plants. 

 Corolla 2-lipped, anticous lobe twice as broad as the 



others ........ 10. 



Corolla not 2-lipped. 



Anther-cells 8, muticous . . . . .11. 



Anther-cells 6, muticous, 2 long-spurred . . 12. 



Anther-cells 4 ; calyx cylindric, ribbed . .13. 



Flowers in axillary clusters ; corolla scarcely ^ in. long 14. 



Flowers solitary ; corolla 1-1^ in. long; leaves linear . 15. 



Pollen globose, ecliinate. Three posticous calyx-lobes 



connate more than half their length (except in D. 



thunbergiifiorus) . . . . . . .16. 



Subtribe iii. STRoniLANxnE^. — Ovules 2 or 1 in each 

 cell. Corolla not or obscurely 2-lipped. 

 Valves of the placenta not rising elastically from the base 

 of the capsule so as to throw out the seeds. 

 Pollen globose, echinate or nearly smooth. 



Pollen strongly echinate . . . . .17. 



Pollen minutely echinate, nearly smooth. Sepals 

 large subcorolloid. Seeds without elastic hairs 18. 

 Pollen globose, honeycombed or reticulate. 



Stamens 4. Calyx cylindric, 5-ribbed . . .19. 



Stamens 2 20. 



Pollen ellipsoid, with 9-15 narrow longitudinal 

 smooth bands. 

 Capsule cylindric, 4-seeded . . . . .21, 



RUELLIA. 



Endosiphon. 



Melleua. 

 Paulo AviLHELMi; 



MlMULOPSIS. 



Physacaxthus. 



Hemigraphis. 



ruelliopsis. 



Distichocaly: 



Acanthopale. 



Whitfielwa. 



Satanocrater. 

 Lankesteria. 



Capsule ellipsoid, flattened, 2 -seeded 



. 22. 



Dyschoriste. 

 Disperma. 



