Jarava [= Stipa sect. Jarava]

Species list

In recent years, there has been a tendency to restore Jarava  to generic rank. The first to do so were Jacobs and Everett (1997) who listed its distinguishing morphological characters as: awn not plumose but upper portion of the lemma bearing long hairs that form an apical pappus; lemma usually less thick than in other species of Stipeae; palea much short than the lemma.  

Other descriptions of Jarava imply a rather broader interpretation. For instance ?? describes it as differing from other genera in the tribe in combining an elongate, narrow neck that often bears conspicuous divergent hairs, a hyaline palea reminiscent of that found in Nassella, and, in many instances, a plumose awn.

Rojas (1998) and Matthei et al. (1998) also recognized Jarava, but extended it to include Achnatherum. Because Jarava has priority over Achnatherum, this implies that all combinations in Achnatherum should be changed to combinations in Jarava.

Penailillo (2002), presents a narrower interpretation of Jarava, restricting it to South American species but expanding it beyond the limits of Ruiz and Pavon to include Stipa subgg. Jarava, Pappostipa, and Ptilostipa plus two other South American species, S. caudata and S. brachychaeta. Under this interpretation, Jarava is a South American genus of 53 species, one of which, J. speciosa, has a disjunct distribution in the southwestern United States and northwestern Mexico.  According Penailillo's interpretation, species of Jarava are characterized by having lemmas or awns with long hairs over some or all of their length and short hyaline paleas or development of axillary cleistogamous aerial panicles, lacking long hairs on the lemmas and awns, and having thickly membranous paleas. The species with axiallary panicles are, in Barkworth's opinion, better included in Achnatherum. They, together with A. clandestinum of Mexico, may represent a distinct lineage within the Stipeae.

Most species of Jarava have glumes that are much longer than the lemma and their leaf blades are involute with well-developed, often continuous, abaxial sclerenchyma.

ITS sequence data support combining Achnatherum and Jarava but the support is weak and based on a small and non-random sample. For now, it seems best to keep the two genera separate while recognizing the possibility that all or many species of Achnatherum should be transferred to Jarava. 

The listing below is taken from Penailillo (2002) 

Literature:
Caro, J.A. and E. Sanchez.  1973.  Las especies de Stipa (Gramineae) del subgenero J..  Kurtziana 7:61-116.
Jacobs, S.W.L. and J. Everett.1997.  Jarava plumosa (Gramineae), a new combination for the species formerly known as Stipa papposa. Telopea 7:301-302.
Penailillo, P. 2002. El genero Jarava Ruiz et Pavon (Stipeae-Poaceae): Delimitacion y nuevas combinaciones.  Gayana 59:27-34.
Rosengurtt, B., B. Arrillaga de Maffei, P. Izaguirre de Artucio.  19970.   Gramineas Uruguayas.  Universidad Publicaciones, Montevideo, Bolivia.
Tovar, O.  1993.  Las Gramineas (Poaceae) del Peru.  Ruizia 13:1-480.