10 PROCEEDINGS OF THE AMERICAN ACADEMY. 



* * Whole plant caneseent-tomentose : leaves linear, entire. 



20. T. candidissima, Gray. Very white-woolly, 4 to 6 inclies 

 high, densely leafy below : leaves 1 to If inches long, sessile by a sheath- 

 ing base : peduncles solitary, terminal, naked : heads homogamous : 

 involucral scales lanceolate, acute : pappus long. — Proc. Am. Acad. xv. 

 39. — On ashy soil, Angostura, San Luis Potosi, Parry ^ Palmer, no. 

 510. Not since rediscovered. 



Subgenus Pseudotridax. Scales of the involucre sub-uniseriate : 

 achenes naerely papillose-puberulent or glabrescent: scales of the pappus 

 obtuse or obtusish, laciniately bordered : anomalous species connecting 

 this genus with Galinsoga. 



21. T. (?) dubia, Rose. Decumbent or procumbent pubescent 



herb; stems about 2 feet long: leaves ovate, serrate, acutish, petiolate : 



heads subracemose or subcorymbose, 6 lines in diameter : involucral 



scales very few, about 5 : ray-flowers with short golden yellow 3-toothed 



ligules. — Contrib. U. S. Nat. Herb. i. 337, t. 33. — Along river bottoms, 



Colima, Palmer, no. 1173; also in lowlands near San Bias, Tepic, 



Lamb^ no. 609. 



Species (doubtless of Eutridax but otherwise) of doubtful affinities: not seen 



by the writers. 



22. T. Ehrenbergii, Schz. Bip. '' Stem herbaceous, elongated, 

 climbing, sulcate, sparingly pilose, trichotomous : leaves rhomboidal, 

 slender-petioled, acuminately serrate, 3-nerved, above sparsely pubescent, 

 below pilose upon the nerves: head solitary, terminal, many-flowered: 

 involucre campanulate : scales scarious, laciniate on the margins : chaflF 

 scarious, trifid, costate, mucronate : flowers of the disk campanulate, 

 pilose, ciliated on the margin: pappus-scales fimbriate, shorter than the 

 sericeous achene." — Leopoldina xxiii. 6. — " Chinantla, Liebmann, no. 

 598. Leaves 20 lines long, 9 lines broad." 



11. — SYNOPSIS OF THE MEXICAN AND CENTRAL 

 AMERICAN SPECIES OF THE GENUS MIKANIA. 



MIK ANI A, Willd. (Dedicated to Professor Joseph Gottfried Mikan, 

 of Prague, born 1743, died 1814.) — Cylindrical involucre of four erect 

 concave obtuse or acute equal or subequal scales, sometimes with a shorter 

 external fifth scale. Receptacle small, naked. Flowers 4 (in M. punctata 

 "7"), tubular, with campanulate throat and 5-toothed limb. Anthers 

 appendaged at the apex, obtuse or truncate at the base. Style-branches 

 Ion"-, filiform-clavellate. Achenes 5-angled, without intermediate ribs, 



