2l6. ACANTHACEAE 507 



37. Flowers in spike- or head-like inflorescences. Calyx-segments usually 



very unequal. Bracteoles very small. — Species 9. Central Africa. 



{Dischistocalyx T, Anders.) Distichocalyx T. Anders. 



Flowers solitary or in neither spike- nor head-like cymes or panicles. . 38 



38. Leaves one-sided (with unequal halves) and usually very unequal in size, 



entire. Flowers solitary. Bracteoles very small. Calyx-segments 

 subequal, very long. Corolla red or blue, with a long cylindrical tube. 

 Anthers included. — Species 2. Equatorial West Africa. 



Endosiphon T. Anders. 

 Leaves equal-sided or nearly so, about equal in size 39 



39. Pollen-grains with many longitudinal ribs. Anthers usually tailed. Calyx- 



segments unequal. Corolla funnel-shaped. Flowers solitary. Bract- 

 eoles small. Leaves linear, entire. Shrubs. — Species 3. East and 



South Africa Ruelliopsis C. B. Clarke 



Pollen-grains netted or pitted. Anthers not tailed. — Species 30. Tropical 

 and South Africa. Some are used as ornamental or medicinal plants. 

 (Including Dipter acanthus Nees) Ruellia L. 



40. (9.) Corolla with imbricate, not ascending aestivation, 2-lipped or nearly 



regular. Filaments free. Anthers, at least those of the anterior 



stamens, 2-celled. Ovules i — 2 in each cell, rarely ( Crabbea) 3 — 4. 



Fruit not distinctly contracted into a stalk. [Tribe BARLERIEAE.] 41 



Corolla with imbricate, ascending aestivation 48 



41. Calyx 4-parted, one of the segments sometimes shortly toothed. Stamens 



2, more rarely 4, exserted. Disc cup-shaped. Stigma-lobes 2, subequal, 

 sometimes nearly confluent. Flowers in cymes, spikes, racemes, or 

 heads. — Species 120. Tropical and South Africa and Egypt. Some 

 are used as ornamental or medicinal plants. (Including Somalia Oliv.) 



Barleria L. 

 Calyx 2- or 5-parted. Stamens 4, included. Disc ring-shaped or indistinct. 



42 



42. Calyx 2-lipped or 2-parted. Corolla folded in the bud, nearly regular, with 



short triangular lobes. Anthers of the posterior stamens i-celled. 

 Disc indistinct. Stigma entire. Inflorescence spike- or head-like. — 

 Species 12. Tropics. (Including Leucoharleria Lindau) 



Neuracanthus Nees 



Calyx 5-parted. Corolla not folded. Anthers 2-celled, rarely those 



of the posterior stamens i-celled, but then corolla 2-lipped. Disc 



ring-shaped 43 



43. Flowers surrounded by 4 united bracts, solitary, with narrow bracteoles. 



Corolla-lobes spreading, pink. Anthers 2-celled. — Species i. Mada- 

 gascar. {Periblema DC.) Boutonia DC. 



Flowers not surrounded by united bracts, solitary but without bracteoles, 

 or in spike- or head-like inflorescences. Corolla two-lipped. ... 44 



44. Bracteoles surrounding the flowers 4, large, exceeding the calyx. Flowers 



in head-like cymes, very small, stalked, intermixed with bracts. Corolla 



