Lasianthaea machucana (Asteraceae), a new species from Jalisco, Mexico

4 Pages·1997·3 MB·English

by  B L Turner

Phytologia (April 1997) 82(4):265-268.
LASIANTHAEA MACHUCANA (ASTERACEAE), A NEW SPECIES FROM
JALISCO, MEXICO
B.L. Turner
DepartmentofBotany,UniversityofTexas,Austin,Texas 78713 U.S.A.
ABSTRACT
A new species, Lasianthaea machucana B.L. Turner, is described and
illustrated from Mpio. Tenamaxtlan, Jalisco, M6xico. It is related to the
widespread L. palmeri, but differs from the latter in a number of characters,
including larger heads with enlarged outer involucral bracts having elongate
spreadinghairs. AmapshowingthedistributionofthesetwotaxainJalisco is
provided.
KEYWORDS: Asteraceae,Lasianthaea,Mexico,Jalisco
Routine identification ofMexican Asteraceae has revealed the following novelty.
This brings to 40 the number of Lasianthaea species to be recognized in my
forthcomingtreatmentofthegenusfortheCompsofMexico(Turner,inprep.).
LASIANTHAEA MACHUCANA B.L. Turner, spec, nov., Figure 1. TYPE:
MEXICO. Jalisco: Mpio. Tenamaxtlan, Recorrido de Tenamaxtlan a los
Picachos, pine-oak woodlands, 20 Aug 1994, J.A. Machuca N. 7217
(HOLOTYPE: LL!;Isotype: GUADA).
SimilisLpalmeri(Greenm.)K.Beckersedbracteaeinvolucri amplificatae
etcoriaceaesunt,serieexteriorefoliiformicumpiliseffusis 1-2mmlongis.
Suffruticoseherbsto50cm high, the roots unknown. Stems moderately hirsute,
mm
thevestitureca. 1 high. Leavesoppositethroughout,ca.5 pair to a stem, shorter
then the intemodes and not much reduced upwards; petioles 2-5 mm long, pilose;
bladesovate,6-7 cm long, 3.0-3.5 cm wide, pubescent above and below with rather
rough stout pilose hairs, especially along the 3-5 major veins which arise somewhat
abovethebase, the margins irregularly denticulate. Heads 3 atthe apices ofprimary
smtmems,the ultimate peduncles 4-8 cm long, pubescent with spreading white hairs 1-2
long. Involucrescampanulate,2-3seriate,theouterseriescomposedof 3-5 leaf-
265
PHYTOLOGIA
266 April 1997 volume82(4):265-268
jHCNBARIUM *BTlIli|lni,*w ,*,*Ill»...* T, ,K »,10- I.I 12i.i.IiiS.i~1.4i.
AUSTIN I[JA
GUUM1.MVH.Mjv^h
Figure 1. Lasianthaeamachucana,holotype.
Turner: NewLasianthaeafromJalisco 267
I05°50'W
I0I°26'W
23°25'N
23°25'N
4-
DUR ZAC SAN
NAY
GUA
JALISCO
• •
MIC
COL
Figure2. DistributionofLasianthaea machucana (triangle) and L. pabneri (circles) in
Jaliscoandcloselyadjacentstates.
PHYTOLOGIA
268 April 1997 volume82(4):265-268
likebracts,pubescentlikethepedunclesand 1.5-2.0timesas long as the inner bracts.
mm mm
Receptacleconvex,ca. 2 across, 1.5 high,paleate,thepales linear-lanceolate,
7-9mmlong,theapices gradually acuminate, purplish. Ray florets ca. 11, pistillate,
mm mm
fertile, the ligules dark yellow, 3-4 wide, 7-10 long. Disk florets ca. 50
mm mm
(estimated);corollasyellow,glabrous, ca. 6 long, the tube ca. 2.5 long, the
lobes broadly triangular, ca. 1 mm long. Raymmachenes (immature) trianguloid,
winged,atthe apex having 2-3 angularcusps 1-2 long; disk achenes (immature)
radiallyflattened,winged,thepappusof2lanceolatepersistentawns2-3mmlong.
ADDITIONAL COLLECTION EXAMINED: MEXICO. Jalisco: Mpio.
Tenamaxtlan, Los Picachos de Tenamaxtlan, pine-oak woodlands, ca. 2100 m, 11
Aug 1996,MachucaN. & ChazaroB. 7932(LL).
Thistaxonbelongstotheherbaceouselements ofLasianthaea, standing somewhat
betweenL aurea(D.Don)K.BeckerandL. palmeri, possessing the short peduncles
oftheformer,butthegeneral habit and uniformly 2-awned disk achenes ofthe latter.
Itdiffersfrombothin having very coriaceous, markedly leaf-like,, apically spreading
mm
outer involucral bracts, which are pubescent with spreading hairs 1-2 long.
Except for the short peduncles and markedly differentiated outer involucral bracts, I
couldhavereadily placedL. machucana underthe fabric ofL. palmeri. As noted by
Becker (1979), L. palmeri is an exceedingly variable species, including dwarf
glabrousformsthat have received the nameL. xylopoda W.W. Jones, which Becker
did not recognize, nor did McVaugh (1984). The distribution of this complex in
Jaliscoandcloselyadjacentregions,sofarasknown,isillustratedinFigure2.
The taxon is named for its collector, aprolific botanist working outof GUADA,
whowasthefirstcollectorofthetaxonconcerned.
ACKNOWLEDGMENTS
I am grateful to Gayle Turner for the Latin diagnosis, and to her and Ted
Delevoryasforreviewingthepaper.
LITERATURECITED
Becker,K. 1979. Amonograph ofthe genus Lasianthaea (Asteraceae). Mem. New
YorkBot. Gard. 31:1-64.
McVaugh,R. 1984. Lasianthaea, in FloraNovo-Galiciana 12:558-575. University
ofMichiganPress,AnnArbor,Michigan.