404 DESCRIPTION OF PLATES. 



PLATE XXV. 



UirncA Breweiu, Watson. — Natural Bize. Fig. 1. Stamhiate flower. Fig. 2. Pistillate flower. 

 Fig. 3. Achcniuin, enclosed by tho largo inner sepals. Fig. 4. Calyx, opened, showing niaturo ache- 

 nium. All enlarged about 10 diameters. 



PLATE XXVI. 



Sisyrinchium Arizonicum, Eothr. — Natural size. Fig. 1. Stamen, seen from outside. Fig. 2. 

 SI amen, seen from Inside. Fig. 3. Styles and stigmas. Fig. 4. Flower, divested of perianth. Fig. . r >. 

 Capsule. All enlarged. 



•PLATE XXVII. 



Tbisetum Wolfii, Vasey.— Fig. 1. Plant, natural size. Fig. 2. Spikelet, enlarged 5 times. Fig. 

 3. Floret, showing the palets and linear seed. 



Trtsetum alpestre, Beauv.— Fig. 4. Natural size. Fig. 5. Spikelet, magnified 6 diameters. 

 Fig. 6. Spikelet, with glumes removed. The last should have shown a little pubescence on the stem of 

 the upper floret. 



Vilfa minima, Vasey.— Fig. 7. Natural size. Fig. 8. Flower, enlarged 15 times. Fi£. 9. Section 

 of stem, greatly enlarged. 



PLATE XXVIH. 



Poa Wheeleri, Vasey.— Fig. 1. Plant, natural size. Fig. 2. Spikelet, magnified 5 times. Fig. 

 3. Upper floret, with rudiment, enlarged 9 times. 



PLATE XXIX. 



Festuca Thurberi, Vasey.— Natural size. Fig. 1. Spikelet, enlarged 5 times. Fig. 2. Upper 

 glume. Fig. 3. Lower glume. Fig. 4. Upper palet. Fig. 5. Lower palet. 



PLATE XXX. 



Nothol^na Hookeri. — Ordinary size. Fig. 1. Scale of tho rootstock. Fig. 2. Scale from the 

 base of the stalk. Fig. 3. Segment of one of the pinnae, showing tho sporangia and the slightly recurved 

 margin. Tho details are enlarged about 6 diameters. 



