44 xcviii. ACANTHACE.E (clarke). [Bi'Ukintaieia, 



Imperfectly-known Species . 



B. hirsuta, 2\ Anders, in Joarn. Agrlc. Hort. Soc. India, N.8. i. 

 1868, 267. 



8. RUEIiLIA, Linn. ; Benth. et Hook. f. Gen. PI. ii. 1077. 



Calyx (in Tropical African species) divided deeply into five subequal 

 segments. Corolla J-^J in. long; tube inflated nearly from the base, 

 or linear-cylindric portion 2-3 in. long ; not decisively 2-lipped ; lobes 

 contorted in bud. Stamens 4, subsimilar ; anther-cells '2, not spurred 

 at the base ; pollen globose, surface reticulate or honeycombed. Style 

 with one oblong-linear branch, the other suppressed; ovary with 6-16 

 ovules, glabrous or hairy. Capsule cylindric, perfecting more than 4 

 seeds. Seeds nearly glabrous on the faces, with much hygroscopic white 

 hair on the margin. Leaves wavy crenate or subentire, not distinctly 

 toothed ; not very unequal at the base, nor those of one pair very un- 

 equal. Flowers axillary, solitary or in small cymes, not running into 

 strobilate spikes. Bracteoles small or large, but not enclosing the 

 calyx. 



Species 20U, in all warm regions. 



The Tropical African species, with two exceptions, belong so far as known to the 

 subgenus D ipter acanthus ; these are recognised generically at a glance by the 

 clavate many-seeded capsule ; when no fruit is present, the herbarium examples can be 

 usually recognised by the honey-combed pollen ; most of the neighbouring genera have 

 ribbed pollen. 



* DiPTERACANTiius. Capsule clavate ; lower portion solid, 

 Bubcjlindric. Seeds imbricated obliquely all near the 

 top. 

 Corolla |-2 in. long ; linear portion of tube less than ^ in. 

 long. Calyx :|-f in. long, teeth usually acute. 

 Ovary (except tip) glabrous. Calyx ^-^ in. long. 

 Leaves petioled. 



Leaves l-l^ in- long, ovate, subobtuse . . 1. Ji. 2)atula. 



Leaves 2-3 in. long, elliptic, tip triangular acute . 2. B. prcetermissa. 

 Leaves subsessile. 



Leaves l-li in. long, elliptic, sparsely hispid . 3. B. sndanica. 

 Leaves 1^ in. long, oblong, hispid . . . A. R. leucoderma. 



Leaves less than h in, long, ovate, scaly . . b. B. placoidea 



Ovary (and capsule) hairy nearly or quite to the base. 

 Calyx J-^ in. long. 

 Leaves 2-3 in. long, elliptic-lanceolate, hispid . . 6. B. pront rata . 



Leaves 2-3 in. long, elliptic, nearly glabrous, lower 



obtuse . . . . . , . . 1. B. (fcnduana. 



Leaves 2 in. long, i in. broad . . . . S. B. linear i-hracteo- 



CoroUa very long ; linear portion of the tube 1-3 in. long. 

 Calyx-teetl) not acute. 

 Innovations with stellately-tomentose hairs. Corolla- 

 tube 1^-2 in. long 9. i?. disclfoliu. 



Plant without stellate hairs. 

 Corolla-tube subcylindric, inflated only close to the 

 top. 



lata. 



