202 PROCEEDINGS OF THE AMERICAN ACADEMY. 



believed that few persons will be disposed to follow the older authors 

 in uniting without distinction of name plants so conspicuously different 

 in their foliage as L. tenuifolia and L. laevigata, yet on the other hand 

 intergradation seems to be demonstrated and there are no differences 

 of much taxonomic significance. To maintain the larger plant as a 

 distinct species on the sole ground of its greater robustness, seems as 

 undesirable as to suppress it altogether. 



II. REVISION OF THE GENUS BARROETEA. 



BARROETEA Gray. (Clarissimo G. Barroeta doctori medicinae 

 et professori scholae metallorum ad oppidum mexicanum San Luis 

 Potosi dictum institutae ob amicitiam suam cum collectoribus botanicis 

 doctoribus Parryo et Palmero petito eorum dedicata.) — Capitula medi- 

 ocria 17-35-flora; involucri campanulati vel turbinati squamis valde 

 inaequalibus appresse imbricatis tenuibus costato-lineatis saepius at- 

 tenuatis raro obtusis vel apice rotundatis mucronulatisque ; receptaculo 

 piano nudo. Corollae tubulatae glabrae pallidae ad insertionem fil- 

 amentorum plus minusve constrictae, faucibus vix uUis, limbo breviter 

 5-dentato. Antherae distinctae vel levissime connatae, apice in appen- 

 dicem latam obtusissimam productae, basi rotundatae integrae. Styli 

 rami clavellati vel apud speciem unicam valde sursum incrassati, paulo 

 exserti. Achaenia valde obcompressa anguste oblonga, margine sursum 

 scabrata vel ciliolata, in facie exteriori vel uninervia vel conspicue uni- 

 costata, in facie interiori 2-3-nervia vel -costata. — Proc. Am, Acad. xv. 

 29 (1879), xvii. 206 (1882) ; Hemsl. Biol. Cent. -Am. Bot. ii. 102 (1881); 

 Hoffm. in Engl. & Prantl, Nat. Pflanzenf. iv. Abt. 5, 142 (1890). 

 Barroetia Hook. f. & Jacks. Ind. Kew. i. 276 (1893) ; Dalla Torre & 

 Harms, Gen. Siphon. 528 (1905). — Herbae graciles annuae vel pe- 

 rennes nonnunquam basi paulo lignescentes saepius ramosae foliosae 

 crispe puberulae vel tomentellae rarius glanduliferae. Folia vel omnia 

 opposita vel superiora alterna ovata petiolata vel sessilia crenati- 

 vel argute serrati-dentata, apice et dentibus saltim posticis in appen- 

 dices setiformes desinentibus. Capitula saepius in panicula laxiuscula 

 foliaceo-bracteata disposita. 



Genus Brickelliae arete affineet eaehabitu, involucro, etc. simillimum 

 differt dentibus foliorum setiferis et praesertim achaeniis valde obcom- 

 pressis 5-6-costatis. 



Species hucusque cognitae 7 omnes mexicanae praecipue montanae et 

 calciphilae locos umbrosos praeferentes, una (n. 1) excepta inter se 

 arctissime affines characteribus quamquam saepe obviis tamen incertis 

 et minus constantibus diagnoscendae. 



