152 B. L. Robinson. 
currentibus, petiolo 4—6 cm longo, foliis supremis deltoideo-ovatis 8—10 cm 
longis 5—7 cm latis subduplice crenato-serratis basi acuminatis, petiolo 
fere a media parte apicem versus alato; panicula ovoidea thyrsoidea 
oppositiramea ca. 7 cm diametro aequialta multicapitulata; capitulis ca. 
10-floris; involucri squamis stramineis in apice obtuso vel rotundato 
brunneis pluriseriatim imbricatis, interioribus lineari-oblongis, exteriori- 
bus gradatim brevioribus ovatis ciliolatis; corollis anguste tubulosis 
glabris dentibus limbi brevissimis; pappi setis sordide albis corollam 
subaequantibus; achaeniis valde immaturis in et etiam inter costis 
pubentibus. 
Yucatan: Izamal (where, acc. to Millspaugh, l. c., in general culti- 
vation, Gaumer, no. 552 (hb. Field Mus., hb. Gray); Merida, Valdez, 
no. 92 (hb. Field Mus., hb. Gray). 
This perplexing plant has several times been referred to the present 
writer, who may well be responsible for some of the several names under 
which it has passed. Renewed study of it shows that it possesses distinctions 
which appear to separate it from any described species. From Æ. qua- 
drangulare it differs in its essentially terete stem; from E. populifolium 
(a species which should henceforth bear the name E. morifolium Mill.) 
it may be readily distinguished by its essentially membranaceous leaves 
of different dentation, and by its pubescent achenes, as well as by its 
half-winged petioles. Its nearest affinity is doubtless, as pointed out by ; 
Dr. Millspaugh, with the West Indian E. aromatisans DC., yet it cannot 
be satisfactorily placed in that species, as the leaves are much thinner, 
the upper ones crenate-dentate, not serrate, and the petioles only 
partially winged instead of being winged clear to the base, as is the 
case in E. aromatisans. 
31. Eupatorium Holwayanum B. L. Robinson, 1. c., p. 40. 
Herbaceum gracile erectum vel decumbens subglabrum 3—5 dm 
altum; caulibus teretibus plus minusve purpurascentibus striatulis obscu- 
rissime puberulis foliosis gracilibus haud 2 mm diametro; foliis ternis vel 
oppositis vel praecipue in parte superiore caulis alternis ovatis vel rhom- 
boideis acutiusculis pauciserratis 1,5—2 cm longis 7—10 mm latis 3- 
nerviis utrinque glabris viridibus basi cuneatis brevissime petiolatis; 
panieula laxe ramosa basi plus minusve folioso-bracteata, ramis gracilibus 
purpureis ascendenti-divergentibus saepius 1--5-capituliferis; capitulis. 
9 mm diametro ca. 60-floris; involucri squamis valde inaequalibus lineari- 
lanceolatis pluriseriatim imbrieatis attenuatis acutissimis striatis viridibus 
vel purpurascentibus; corollis albis 3,3 mm longis tubulosis, tubo proprio 
brevissimo, faucibus anguste tubulosis multo longioribus glabris, dentibus 
limbi 5 externe puberulis; achaeniis 5-angulatis fuscescentibus 1,7 mm 
longis in angulis scabratis; pappi setis ca. 20 albis tenuissimis scabratis. 
Mexico: Dry banks, Sierra de San Felipe, alt. 2150 m, 17 Nov. 1894. 
C. G. Pringle, no. 5683 (hb. Gray) 14 Nov. 1903, E. D. W. Holway, 
no. 5418 (hb. Gray). 
This plant was at first referred to E. trinervium Sch. Bip., to which. 
