Questioned Distributional Records.

A few of our distributional records disagree with those presented elsewhere. Most instances reflect disagreement over the appropriate taxonomic status. For instance, Jorgensen & León-Yánez (1999) did not show N. depauperata as occurring in Ecuador because they regarded it as a synonym of N. inconspicua. In our opinion, the two taxa are quite distinct, with both meriting recognition as species. Nassella depauperata has smooth lemmas whereas N. inconspicua has lemmas that are minutely papillose all over. These authors also reported N. manicata as occurring in Ecuador, but noted that they had been unable to examine the specimen that purportedly documents the species’ occurrence there.

Similarly, some authors include N. rupestris in N. depauperata, but we regard them as distinct.  They differ by the characters shown in Tables 5 and 6 plus two others: N. depauperata has involute leaf blades and a persistent awn whereas N. rupestris has convolute leaf blades and a thinner, deciduous awn. Nassella dasycarpa is also similar to N. rupestris, but N. rupestris has culms that are taller with respect to the basal leaves, has finely pubescent pedicels and paleas, and glumes that are shorter and thinner than those of N. dasycarpa. In N. dasycarpa, the leaves reach about 2/3 of the total plant height, the pedicels and the palea are glabrous, and the glumes and anthoecia are slightly longer (Tables 5, 6).

Reports of N. nutans occurring in Uruguay are based on records of S. nutans var. quinqueciliata which we recognize as N. quinqueciliata. Nassella nutans sensu stricto grows in Brazil and possibly in Argentina (we have not been able to verify this) whereas N. quinqueciliata appears to be restricted to Uruguay. The two differ not only in the vestiture of the lemma but also in the length of their anthoecia and awns (Tables 5, 6). Similarly, N. pauciciliata differs from N. megapotamica in having a longer, stiffer column, in the color of its lemma at maturity, and in its lemma pubescence. Examination of the type of  N. tucumana revealed that, in addition to florets with a non-shiny, minutely papillose lemma described by Parodi (1948), it has some with shiny, smooth (or almost smooth) lemmas, characteristics by which N. asperifolia differs from N. tucumana.  specimens of N. asperifolia and N. tucumana lead us to conclude that the two are conspecific, so we have listed N. asperifolia as a synonym of N. tucumana.

We question Peñailillo’s (1998) report that N. tenuiculmis grows in Argentina based on examination of five of the seven specimens he cited, none of which belongs to N. tenuiculmis. One (Boelcke, Matthei, & Correa 9385 in BAA) belongs to Stipa juncoides, and four (Ragonese & Piccinini 8860 and 9231; Correa & Nicora 3157, all in BAB; Krapovickas & al. 22299 in CTES) to N. tenuis. Nassella tenuiculmis differs from both N. tenuis and S. juncoides in having rhizomes, extravaginal innovations, and longer lemmas with pubescent veins. Stipa juncoides resembles species of Nassella in having a short, glabrous palea and a crown, but it differs from them in having a less coriaceous, weakly overlapping lemma and in its lemma epidermal pattern, which resembles that of S. filifolia and S. hypsophyla (Torres 1993). It should probably be excluded from Stipa, but determining a more appropriate generic treatment is beyond the scope of this study.