STANbLEY TBEES AND SHRUBS OF MEXICO 1421 



2. Ageratum albidum (DC.) Hemsl. Biol. Centr. Amer. Bot. 2: 81. 1881. 

 Coelestina albida DC. Prodr. 5: 107. 1836. 



Carelia albida Kuntze, Rev. Gen. PI. 1: 325. 1891. 



Oaxaca; type collected between Oaxaca and Mitla. 



Herbaceous or suffrutescent, up to 60 cm. high; leaves short-petioled, the 

 blades ovate, 2.5 to 6 cm. long, 1.5 to 3.8 cm. wide, obtuse or merely acute, 

 densely dull-pilose beneath, the glands pale and obscure; flowers white. 



This species is described by Robinson as an herbaceous perennial, as it is in 

 two of the sheets in the National Herbarium; Nelson's no. 1208, however, is 

 truly woody below. 

 2a. Ageratum albidum nelsonii Robinson, Proc. Amer. Acad. 49: 471. 1913. 



Oaxaca; type collected between Zanantepec and Papana. 



Leaves larger and thinner, broadly ovate, 6 to 11 cm. long, 2.5 to 4.5 cm. 

 wide; petioles longer; corollas apparently bluish. 



3. Ageratum elassocarpum Blake, Contr. U. S. Nat. Herb. 22: 588. 1924. 

 Known only from the type locality. Sierra de TonaM, Chiapas. 



Base not seen; stem herbaceous above, over 50 cm. high; leaves on petioles 

 8 to 15 mm. long, the blades triangular-ovate, 3.5 to 7 cm. long, 1.5 to 2.8 cm. 

 wide, narrowed to an obtuse tip, rather dull above, beneath equally green, 

 puberulous along the veins and densely punctate with light glands; heads small, 

 4 mm. high, the phyllaries and pales somewhat indurate-cuspidate; achenes 

 1.3 mm. long. 



4. Ageratum tomentosum (Benth.) Hemsl. Biol. Centr. Amer. Bot. 2: 



84. 1881. 

 Coelestina tomentosa Benth. in Oerst. Nat. For. Kjobenhavn Vid. Medd. 



1852: 71. 1852. 

 Carelia tomentosa Kuntze, Rev. Gen. PI. 1: 325. 1891. 



San Luis Potosf and Puebla to Costa Rica; type from Candelaria, Costa Rica. 

 Herbaceous or suffrutescent; leaves short-petioled, the blades ovate to triangu- 

 lar-ovate, 2 to 6.5 cm. long, 1 to 4 cm. wide, obtuse, dull above, densely whitish- 

 tomentose beneath; flowers bluish purple or white. 



5. Ageratum corymbosum Zuccagni; Pers. Syn. PL 2: 402. 1807. 

 " Sparganophorus ageraioides Lag. Elench. PL 25. 1815." 

 Ageratum coelestinum Sims in Curtis's Bot. Mag. 42: pi. 1730. 1815. 

 Coelestina coerulea Cass. Diet. Sci. Nat. 6: Suppl. 8. 1817. 

 Coelestina ageratoides H. B. K. Nov. Gen. & Sp. 4: 151. 1820. 

 Coelestina suffruticosa Sweet, Hort. Brit. 229. 1826. 



Coelestina corymbosa DC. Prodr. 5: 108. 1836. 



Coelestina lessingiana Klotzsch; Walp. Repert. Bot. 2: 545. 1843. 



Carelia corymbosa Kuntze, Rev. Gen. PL 1: 325. 1891. 



Coelestina sclerophylla Woot. & Standi. Contr. U. S. Nat. Herb. 16: 176. 1913. 



Sonora to Zacatecas and the Valley of Mexico. Texas. Type locality not 

 stated. 



Suffrutescent or fruticose, up to 70 cm. high; leaves very variable, the blades 

 2 to 11 cm. long, ovate to oval or rarely lanceolate, obtuse to acute, from nearly 

 glabrous to dull grayish-tomentose beneath, dotted with pale or reddish glands; 

 flowers violet or white. "Cielitos." 



Numerous varieties and forms based on leaf form and color are described by 

 Robinson.^ 



1 Proc. Amer. Acad. 49: 475-477. 1913. 



