212 PATAGONIAN EXPEDITIONS: BOTANY. 



flowered, narrow, with a joint above the lower glumes, the uppermost 

 flower often male. Empty glumes 2, carinate ; floriglume broad at base, 

 obscurely many-nerved, divided into many awn-like lobes; 2-3 upper 

 glumes empty or with a rudiment. Palea broad, 2-carinate. Grain en- 

 closed in the palea and floriglume, free. 

 Species 20, in warm countries. 



P. MUCRONULATUM NeCS. 



Culm branching. Leaves attenuate-acuminate, convolute, glabrous as 

 are the sheaths. Panicle spicate, narrow, long, cernuous ; spikelets nearly 

 4-flowered. Glumes subequal, oblong, membranaceous, setaceous-mucro- 

 nate r i -nerved; 2 (rarely 3) lower flowers perfect. Floriglume subcori- 

 aceous, silky-strigose, 4-cleft. 



(Brazil) ; N. Patagon., not rare in dry places near Carmen, and at the 

 mouths of Rio Negro. 



39. PHRAGMITES Trin. (Arundo Beauv.) 



Tall perennials, with large flat blades, and spikelets 2-many-flowered, in 

 a large much-branched panicle, rachilla elongated and articulate between 

 the flowers, and covered with long hairs. Ghimes thin, keeled, pointed, 

 the florighime ^with a longer point, the lowest flower being male or abor- 

 tive. (This last character distinguishes from Arundo Linn.) 



Species 2, over warmer parts of both worlds, in wet places. 



P. PHRAGMITES (Linn.) Karst. 



Cidms 2-3 m. high; blades often 3 cm. wide. Panicle 15-35 cm - l n g- 

 Spikelets 3-5-flowered, 16 mm. long, the silky hairs as long as the 

 flowers. Glumes with nerves anastomosing towards the apex. Flori- 

 glume 5-nerved, 12 mm. long. 



(Cosmopolitan in N. Hemisphere and Australia) ; Chubut, in swamps, 

 and near Carren-leofu. The Patagonian forms always have 3-flowered 

 spikelets, the upper flower often reduced. 



40. MONANTHOCHLOE Engelm. 



Creeping or stoloniferous, with crowded distichous leaves, less than i 

 cm. long. Spikelets unisexual, almost immersed in leafy bracts. Empty 

 glumes like the leaves. Floriglume obtuse or toothed. Stamens 3. 



