FIELD COLUMBIAN MUSEUM BOTANY, VOL. III. 



as refrigerants, especially in gonorrhoea in which trouble they are 

 said to prove highly beneficial. 



Hab. Shady, cool situations, particularly at the mouths of caves. 

 Ruins of Uxmal, Schott 687 ; mouth of the cave of the Great Mound 

 at Izamal, Jan. 13, 1895, Millspaugh Armour Exped. 54, and on the 

 north aspect of the Monjas, Chichen Itza, Jan. 17, 1895, 112; Izamal, 

 Jan., Gaumer j86, and in patches on large stones in deep woods at 

 Calotmul, 1725, and Chichankanab, //2j, 1724; near Merida, Valdez 

 64; and in a cave near Calcehtoh, Stone 263. 



Adiantum tenerum Sw. Fl. Ind. Occ. 1719. 

 A. trapezoides Fe"e. 



Stipes shining, glabrous. Frond 3-4-pinnate; segments mem- 

 branaceous, glabrous, obliquely rhomboid, blunt at the apex, more or 



less incised into 3-5 partial 

 lobes at the free fertile mar- 

 gins, and jointed to the pedi- 

 cels; veins filiform, once to 

 twice forked. Sori marginal 

 beneath the recurved denta- 

 tions of the apex, which form 

 small, oblong indusiae; spo- 

 rangia nearly circular, jointed 

 to the pedicel, closely and 

 finely anastomose-reticulate; 

 spores triangular with slightly 

 concave sides, the angles con- 

 nected by a three-forked hya- 

 line ridge. 



The pinnule in the cut is 

 natural size. Stipes 12-45 cm. 

 or often a full meter in length. 

 In fruit throughout the dry season, from November until March. 



Hab. Mouths of caves, walls of cenote"s, and on rocks in cool, 

 shady woodlands. Merida, Quinta de Encalada, Schott 92, and the 

 Cenote" of Kikil, 778 ; mouth of a cave near Izamal, Gaumer 1071, and 

 in deep woods at San Anselmo, 2140, 2442, and Chichankanab, 1516. 



PTERIDIUM. 



Fronds once to twice pinnate, or decompound. Sori a complete 

 continuous slender line occupying the entire margin of the fertile 

 segments and covered by their recurved narrow edge which forms an 

 uninterrupted, membranaceous indusium, attached to a continuous 

 transverse vein-like receptacle, connecting the tips of the forked and 

 free veins. 



Pteridium caudatum (L.) Maxon. 



Pteris caudata Linn. 



Fronds pale yellow-green, stiff and ligneous, 3-pinnatisect; seg- 

 ments elongate-deltoid, blunt, or in fruit often acute, the ultimate 

 segment about one-third the length of the pinnule, all oblique at the 

 shortly decurrent base, and scattered lax-hairy along the midrib. 



