636 PROCEEDINGS OF THE AMERICAN ACADEMY. 
ceeded by the leaves, and in the lack of leaf-like bracts subtending the 
larger branches of the inflorescence. From one another they differ 
most markedly in the size and dentation of the leaves, but also in the 
character of the pubescence on the upper leaf-surface. In P. Stramo- 
nium it is velvety, in P. Arctium arachnoid-tomentose. In P. Stra- 
monium the panicle is nodding, in P. Arctium it is upright. Both 
species occupy the same floral region and are the northwestern congen- 
ers of the southeastern P. tomentosum and its allies. 
Parthenium Lozanianum, n. sp., fruticosum ramosum usque ad 
2.5m. altum, ramis ochraceis subsulcatis juventate exigue albo-tomen- 
tosis, aetate glabris ; internodiis quam foliis saepe duplo brevioribus. 
Folia plerumque lyrato-partita 2-4.5 em. lata 4-9 em. longa, supra Viti- 
dia exigue crispo-pubescentia, subtus molliter albido-tomentosa, parte 
terminali circumscriptione triangula vel cuneato-lanceolata ipsa fere 
generis Aceris modo obtuse dentata lobataque, partibus inferioribus 
parvis vel nullis basi in petiolum 3-6 mm. longum decurrentibus. In- 
florescentia terminalis ex corymbis 5-6 sublaxis constans. B 
deorsum foliis superioribus similes sursum gradatim minores et lan- 
ceolatae vel lineares. Inflorescentiae ramuli pedicellique puberulo- 
tomentosi graciles. Capitula diametro et altitudine ca. 5 mm. Tnvoluert 
Squamae 10 biseriatae exteriores late ovatae acutiusculae interiores 
suborbiculares basi truncatae apice obtusissimae. Radii flores 5, tubo 
revi, limbo suborbiculari apice emarginato aut raro tridentato. 
Achenia nigra hirtella compressa cuneata 2.5 mm. longa ad margines 
singula palearum aristis floram duorum sterilium adnata. Pappi aris- 
tae 2 nigrae arcuato-ascendentes tubum superantes albo-pubescentes. 
Disci flores ca. 26 in axillis palearum cuneatarum pubescentium posttl. 
— Nuevo Leon, State of Nuevo Leon, alt. 300 m., Lozano, no, 10,247 
(type, in hb. Gray). A member of De Candolle’s section Parthent- 
chaeta and very closely allied to P. incanum HBK., from which it 
may be distinguished by its incuryed, ascending pappus-awns and greet 
upper leaf surface. In P. incanum the pappus-awns are divergent or 
often recyrved, and the leaves are whitened above. : 
_ PEREZIA apNaTA Gray. This species has long been considered iden- 
tical with Perezia Alamani Hemsl. Specimens which have accumt 
lated in recent years afford evidence that not only may Perezia adnata 
and P. Alamani be distinguished, but also a third plant which 1s here 
described as a variety of the former. The following brief descriptions 
contrast the diagnostic characters of the three plants. 
‘PeRezia Atamant (DC.) Hemsl, involucri bracteis ca. 14 psene 
glabris submembranaceis anguste lanceolatis viridibus apice purpureo- 
tinetis basi vix callosis ; pappi setulis ca. 49; labro corollae interiore 
