1958] 



THE BOTANY OF THE GUAYANA HIGHLAND PART III 



23 



13. Spikelets pedicelled, the inflorescence subumbellate, subtended by a solitary 

 lanceolate bract, each pedicel subtended by a similar but smaller bract ; 

 anthers 4-celled, dehiscing by a subapical lateral pore ; capsule refuse ; leaves 

 broadly linear, not gramineous. 15. Windsorina. 



12. Inflorescences short-pedunculate, not at all or barely exserted from the sub- 

 tending leaf -sheaths ; filaments pubescent, much exceeding the corolla ; anthers 

 unilocular, dehiscing by a solitary subapical pore; African 16. MasclialocepJiahis. 



Saxofriderieioideae, Saxofridericieae 

 Saxofridericia Rob. Sehomburgk, Rapatea Frid. Aug. Saxo-Frid. Reg. 13. 1845. 



Peduncles solitary, axillary; involucral bracts spathaceous, foliaceous, bi- 

 valved, the margins often connate, therefore often saccate ; inflorescence at ma- 

 turity globose or hemispheric; spikelets numerous, sessile, or with very short 

 stalks, irregularly subtended by several conspicuous or inconspicuous membra- 

 nous bracts ; sepals free to the base ; petals obovate or suborbicular, at anthesis 

 the claws connate into a conspicuous membranous tube ; filaments adnate to the 

 corolla tube, the anthers lanceolate, transversely rugose, tapered upwards, 4-lobed, 

 the anterior locules extending to subterminal anterior pores, the posterior locules 

 projected as a somewhat cucullate appendage ; ovary trilocular, the locules pluri- 

 ovulate; style subulate-trigonous, acute; stigma terminal, minute; capsule oblong- 

 obovate. membranous below, indurate above, loculicidal, the placentation axial, 

 the distal portion of the axis interrupted and the septa withdrawn to the walls; 

 seed semi-annulate transversely rugose and striate. 



Robust perennial herbs; a genus of nine species, five belonging to subg. 

 Eusaxofridericia, confined to montane regions of the Guayana Highland, and 

 the other four to subg. Acrotheca, these being plants of periodically inundated 

 regions of lowland Ilylean rain-forests, two within Guayana, two extra-Guayanan. 



Type species: Saxofridericia regalis Rob. Sehomb. 



.. Key to the Species and Subspecies of Saxofridericia 



1. Bractlets of the spikelets lanceolate or ovate-lanceolate, gradate; mature heads mas- 

 sive, 4 cm or more broad; plants of montane habitats (subg. Saxofridericia). 

 2. Petioles lacking, i.e. the leaf-blade emerging directly from the summit of the 

 leaf -sheath. 



3. Peduncles gradually enlarged below the inflorescence. 



4. Secondary bracts (enclosed by the primary involucral bracts) numerous, mem- 

 branous, inwardly decreasing in size, the outer lanceolate, acuminate, 4-5 cm 

 long; plants of the eastern Guayana Highland. 1. S. regalis. 



4. Secondary bracts (exclusive of spathaceous bracts) lacking, or inconspicuously 

 small, membranous, and chaff-like; plants of the western Guayana High- 

 land. 2. S. duidae. 

 5. Spikelets 20-22 mm long; bractlets' maximum size 5 X 14 mm with the 



acumen ca. 0.5 mm long, the nerves 7, inconspicuous. S. duidae subsp. duidae. 

 5. Spikelets 18 mm long; bractlets' maximum size 3 X 12 mm with the acu- 

 men ca. 1.0-1.5 mm long, the nerves 7-9, conspicuous. 



S. duidae subsp. marahuacensis. 

 3. Peduncles abruptly enlarged and bulbose (in broad outline) below the inflores- 

 cence; plants of the western Guayana Highland. 

 6. Peduncles strongly and sharply compressed, the margins very acute or nar- 

 rowly winged ; leaf -sheaths not spongiose, 4-5 cm broad ; leaf -blades 4-5 cm 

 broad; spikelets 20-24 mm long; petals broadly obcordate, 25-30 mm broad. 



3. S. compressa. 



6. Peduncles moderately compressed, without Avinged or sharp margins; leaf- 

 sheaths thickly spongiose, 8-10 cm broad; leaf -blades 7-10 cm broad; spike- 

 lets 26-32 mm long; petals rhomboid-orbicular, 18-20 mm broad. 4. S. spongiosa. 

 2. Petiole 10-15 cm long, connecting the summit of the gibbose, lanceolate leaf- 

 sheath and the blade proper; plants of the western Guayana Highland. 5. S. grandis. 



