A new species of Ageratina (Asteraceae, Eupatorieae) from Nuevo León, México

2 Pages·1993·0.89 MB·

by  B L Turner

Phytologia(Axignsi 1993)75(2):147-148.
A NEWSPECIES OF AGERATINA(ASTERACEAE. EUPATORIEAE)FROM
NUEVO LEON, MEXICO
BillieL. Turner
DepartmentofBotany,UniversityofTexas, Austin,Texas 78713 U.S.A.
ABSTRACT
AnewspeciesofAgeratina,A. viejoanaB.L. Turner,isdescribed
fromCerroViejo,southernNuevoLeon. Itappearsontechnicalcharac-
terstobelongtothesubgenusAgeratina,havingthepubescentcorollas
ofthespeciesofthattaxon,butontotalcharactersit seemsclosestto
speciesbelongingtothesubgenus Neogreenella.
KEYWORDS: Asteraceae,Eupatorieae, Ageratina,Mexico
Routine identification of Mexican Asteraceae has revealed the following
novelty.
AgeratinaviejoanaB.L.Turner, sp. nov. TYPE: MEXICO. NuevoLeon:
Mpio. Zaragoza, Cerro El Viejo, oak and pine woods, 2405 m, 12 Oct
1992, Hinton et al. 22484(HOLOTYPE: TEX!).
Speciei Mexici AgeratinaepereziiB.L. Turner similissed foliis
tenuioribuspetiolis gracilibusmultolongioribus (30-35 mmlongis
mm
vs. 10-15 longis)etcorollispurpurascentibus(vs.albis)differt.
SufFruticose herbs or subshrubs ca. 60 cm high. Stems striate, greenish,
denselypubescentwithglandular-puberulenthairs0.1-0.2mmhigh. Midstem
leaves 10-12 cmlong, 5-6 cmwide; petioles3.0-3.5 cmlong; blades deltoidto
subcordate,3-nervatefromtheverybase,moderatelysoft-puberulentbeneath,
the margins crenulate. Heads ca. 20, arranged in terminal loose bracteate
cymes,theultimatepedunclesmostly5-20mmlong,denselyglandular-puberu-
mm
lent. Involucres campanulate, the bracts ca. 13, subequal, 8-10 long,
densely glandular-puberulent. Receptacle plane, glabrous. Florets 15-20 per
head(estimated). Corollasca.6.5mmlong,pinkish-purple,thetubeca.2mm
147
PHYTOLOGIA
148 volume 75(2):147-148 August 1993
mm
long, the lobes ca. 1 long, decidedly pubescent with multiseptate hairs.
Achenes(immature)cylindric,ca. 2.5 mmlong, hispidulous; pappus of20-30
mm
fragilebristlesca. 5.5 long.
ADDITIONALSPECIMENEXAMINED:samelocaUtyanddateastype,
Hinton et al 22504 (TEX).
Thisspeciesand Ageratinaperezii,withwhichitiscomparedintheabove
diagnosis, belong to the subgenus Ageratinaas defined by King & Robinson
(1987), both having the fragile pappus and pubescent corollas of that sub-
genus. Nevertheless, both clearly resemble the widespread A. cardiophylla
(B.L. Robins.) R.M. King & H. Robins., having the foliage and vestiture of
that taxon. Ageratina cardiophyllabelongs tothesubgenus Neogreenella, the
lattertechnicallyrecognizedbyitstubular,glabrouscorollas. Itwouldappear
thatthe"definingcharacters"ofthesetwosubgeneraoccasionallybreakdown
among those species of Mexico having cordate leaves, or else cordate leaves
haveariseninparallelinboth.
ACKNOWLEDGMENTS
Iamgratefulto Guy Nesomforthe Latindiagnosis, and tohimandT.P.
Ramamoorthyforreviewingthemanuscript.