STANDLEY TREES AND SHRUBS OF MEXICO. 137 



Avith gray-brown spine 3 mm. wide and 20 mm. long, and conspicuously unequal 

 and variously curved, narrowly triangular teeth 20 to 30 mm. apart and 3 to 

 7 mm. long. 



When the median stripe is most pronounced it is var. univittata (A. univittata 

 Haw. Phil. Mag. 10: 415. 1S31) ; but the marking is not confined to this species. 



141. Agave horrida Jacobi, Hamb. Gart. Zeit. 20: 546. 1864. 



Morelos, abundant above Cuernavaca on the lava fields ; type cultivated in 

 Europe without indication of locality. 



Leaves uniformly spreading, rather thin, green, without ventral stripe or dor- 

 sal lines, 6 to 7 cm. wide, 30 cm. long, with red-brown graying spine 3 mm. wide 

 and 20 to 40 mm. long, and large flat hooked teeth 15 to 30 mm. apart and 5 to 

 15 mm. long, the connecting undulate horny border 2 to 3 mm. wide. 



142. Ag'ave roezliana Baker, Gard. Chron. n. ser. 7: 528. 1877. 



Agave horrida laevior Jacobi, Wochenschr. Ver. Beford. Gartenb. 1869: 178. 

 1809. 



Puebla ; type cultivated in Europe, but now known to have come from Te- 

 huacSn. 



Leaves uniformly spreading, thick, green, sometimes with paler ventral stripe 

 but not dark-lined on the back, 5 to 10 cm. wide, 30 to 40 cm. long, with 

 brown or fading spine 3 mm. wide and 20 to 25 mm. long, and heavily triangular 

 teeth 10 to 15 mm. apart and 6 to 20 mm. long, the nearly straight horny inter- 

 vening margin 1 to 3 mm. Avide. 



Plants with very short and broad leaves and exceptionally large teeth consti- 

 tute var. nana {A. horrida nana Laurentius, Cat. 1869: 12. 1869; A. gilbeyi 

 horrida Baker, Gard. Chron. 1873: 1305. 1873) ; and a form with elongate, nar- 

 rowly oblong leaves and often reduced teeth is var. peacockii (A. peacockii 

 Croucher, Gard. Chron. 1873: 1400. 1873). 



143. Agave ghiesbrechtii Koch, AVochenschr. Ver. Beford. Gartenb. 5: 83. 1862. 

 Region ? ; type cultivated in Europe. 



Leaves upcurving, concave, fleshy, grayish green or bluish green, without dis- 

 tinct ventral stripe or dorsal lines, 5 to 7 cm. wide, 18 to 20 cm. long, with 

 spine scarcely 15 mm. long, and gray, triangular, nearly straight teeth scarcely 

 10 mm. apart and 5 mm. long, the connecting horny border under 2 mm. wide. 



The form with shorter, more heavily bordered leaves is A. rohanii Jacobi 

 (Hamb. Gart. Zeit. 20: 54.5. 1864) ; and that with elongate, narrowly bordered 

 leaves is A. leguayiana J. Verschaft'elt (Pr. Cour. 1868: 2. 1868). 



144. Agave obscura Schiede, Linnaea 18: 413. 1844. 



Agave grandidentata Jacobi, Hamb. Gart. Zeit. 22: 114. 1866. 



Agave horrida micracantha Baker, Gard. Chron. n. ser. 7: 621. 1877. 



Veracruz ; common on the lava beds about Limon ; type locality, lava fields 

 of La Joya. 



Densely subglobose ; leaves uniformly spreading, gray, 10 cm. wide, 30 cm. 

 long, with gray spine 3 to 8 mm. wide and 25 to 30 mm. long, and triangular, 

 straight or variously curved teeth 5 to 10 mm. apart and 3 to 5 mm. long, the 

 intervening margin 1 to 2 mm. wide. " Lechuguilla." 



145. Agave triangularis Jacobi, Wochenschr. Ver. Beford. Gartenb. 1869: 178. 

 1S60. 



Puebla ; type cultivated in Europe from near TehuacSn. 



I.ieaves ascending, thick and very rigid, dull gray-green, without ventral stripe 

 or .dorsal lines, about 5 cm. wide and 25 cm. long, with gray spine 3 mm. wide 

 and 20 to 25 mm. long, and large, gently curved teeth 15 to 25 mm. apart and 5 

 to 15 mm. long, the nearly straight intervening margin 1 to 2 mm. wide. 



With numerous but small teeth it is var. rigidissima (A. rigidissima Jacobi, 

 Wochenschr. Ver. Beford. Gartenb. 1869: 179. 1869) ; and with few and 



