Gynerieae, a new neotropical tribe of grasses (Poaceae)

3 Pages·2001·1.7 MB·

by  L G Clark

Gynerieae, a New Neotropical Tribe of Grasses (Poaceae)
J. Gabriel Sanchez-Ken & Lynn G. Clark
Department of Botany, Iowa State University, Ames, Iowa 50011-1020, U.S.A.
Abstract. Gynerium was traditionally classified lection, however, was limited to two species from
in the reed tribe Arundineae in the Arundinoideae, outside of the PACC clade, and therefore alterna¬
but recent molecular studies strongly support its tive topologies were not rigorously tested. More de¬
affinities with the Panieoideae + Centothecoideae tailed analyses of the PACC clade, as part of an
clade. A new tribe, the Gynerieae, is described to analysis ol IIS sequence data for the entire family
accommodate Gynerium. (Hsiao et al., 1999), confirmed the placement of
Key words: Gynerieae, Gynerium, Neotropics, Gynerium within an arundinoid clade, but bootstrap
Poaceae.
values were very' low. In contrast, Barker (1997),
using plastome rbcL sequence data, placed Gyner¬
Gynerium P. Heauvois, known as eaiia brava or
ium within a Panieoideae + Centothecoideae clade,
giant reed, is a widespread. Neotropical, reed-like either as sister to the Panieoideae or sister to Thy-
grass. The genus is characterized by its reedy habit,
sanolaena in the Centothecoideae, with moderate to
tightly distichous leaves, leathery blades with wide good support values.
midribs, dioecy, and plumose pistillate synfloresc- The (bass Phylogeny Working Group (GPWG,
ences. The plants are probably the tallest among 2000, 2001) combined eight character sets, both
the grasses, excluding the woody bamboos, with
molecular and morphological, in phylogenetic anal¬
some culms per population reaching 10(-15) m in
yses of the entire Poaceae. Only four of these data
height. This monotypic genus is distributed from sets (r&cL, rpoC2, ITS, and morphology) were avail¬
southern Mexico to northeastern Argentina, as well able for Gynerium, but in the combined analyses,
as in the West Indies, and occurs along river banks
Gynerium was placed within the Panieoideae +
and in swampy habitats. Locally, the culms are
Centothecoideae clade, whose monophyly was rea¬
used for construction and decoration, and the pe¬ sonably well supported (Fig. 1). Within this clade,
duncles are used as shafts for hunting arrows (Kal-
Gynerium appears as sister to the Panieoideae, but
liola & Renvoize, 1994).
with only moderate support values at best. Prelim¬
Due to the resemblance in habit and synfloresc- inary results based on molecular and morphological
ences, Gynerium has traditionally been classified
data from a more detailed study of the Panieoideae
with the other common reed-like grasses, including
and Centothecoideae subclades corroborate the
Arundo L. and Phragmites Adanson, in the tribe
placement of Gynerium within the Panieoideae +
Arundineae (Kunth, 1833; Renvoize, 1981; Clayton
Centothecoideae (Sanchez-Ken & Clark, 2000; E.
& Renvoize, 1986; Conert. 1987; Dallwitz et ah,
A. Kellogg, pers. comm.), but its position remains
1999). In a few other classifications, however, Gy¬ unstable within this clade.
nerium was included in other tribes such as the
Gynerium is strongly supported as a member of
Festuceae (Hitchcock. 1914), Cortaderieae (Caro,
the Panieoideae + Centothecoideae clade, but ro¬
1982), or Danthonieae (Watson & Dallwitz. 1992).
bust resolution ol its phylogenetic position within
All of these classification systems were based on
this clade awaits further study. Nonetheless, the ge¬
morphological and anatomical features.
nus appears to be isolated from other tribes and
Analyses of individual molecular sequence data genera in this clade, including the reed-like Thy¬
sets provided conflicting results with respect to the
sanolaena, which is embedded within the Cento¬
phylogenetic relationships of Gynerium. Hsaio et al.
thecoideae. We therefore propose tribal status for
(1998). based on nuclear ribosomal internal tran¬
Gynerium, but cannot confidently place it in either
scribed spacer (ITS) sequences, supported a mono-
the Panieoideae or Centothecoideae al this time.
phyletic Arundinoideae, including Gynerium. Other
taxa traditionally referreil to this subfamily, such as Gynerieae Sanchez-Ken & I,. G. Clark, tribus nov.
Thysanolaena Nees, Micraira 1’. Mueller, and the TYPE: Gynerium P. Beauvois.
danthonioid grasses, were also resolved as members
Plantae perennes, rhizomatosae, dioeeiae; culmis 2-
of the Arundinoideae, although Hsiao et al. did not
10(—15) m aids; interriodiis solidis. Folia disticha; vaginis
recover a monophyletic Arundineae. Outgroup se-
quam internodiis longioribus, arctis, persistentibus; lam-
Novon 11; 350-352. 2001.
Volume 11, Number 3 Sanchez-Ken & Clark 351
2001 Neotropical Tribe of Grasses
Thysanolaena
Zeugites C
Chasmanthium
Gynerium
Danthoniopsis
Panicum
Pennisetum P
Mis can thus
Zea
Figure 1. Phylogeny of the Panicoideae + Centothecoideae clade from GPWG (2001), with bootstrap values above
tbe branches and Bremer support values below. C = Centothecoideae; P = Panicoideae.
inis (0.4—)1.5—2 m longis, coriaceis, articulatis, non pseu- opsis oblong, hilum punctate. Chromosome num¬
dopetiolatis, costa 0.5-1.5 cm lata, plerumque conspicua. ber: x = 1 1.
Synflorescentiae paniculatae, pistillatis plumosis. Spiculae
pistillatae biflosculatae; glumis inaequalibus, inferiore The name is taken from the Greek gyne, "wom¬
membranacea, superiore coriacea, longiore quam flosculis; an,” and erion, “wool,” referring to the pistillate
lemmatibus sursum villosis, ad apicem elongatis, attenu-
spikelets. This tribe includes one genus with only
atis, non aristatis; lodiculis 2, truncatis, membranaceis;
stylis 2, liberis; rachillae extensione carente. Spiculae one species, G. sagittatum (Aublet) P. Beauvois,
staminatae 2- ad 4-flosculatae; glumis inaequalibus; lem¬ which is distributed from the Caribbean and south¬
matibus glabris vel sparsim breviter pilosis; lodiculis 2; ern Mexico to tropical Argentina.
staminibus 2.
Acknowledgments. We thank CONACyT-Mexi-
Plants perennial, rhizomatous, dioecious, stami-
co (fellowship 119472) for its sponsorship of the
nate and pistillate plants similar in gross morphol¬
first author. Final preparation of the manuscript was
ogy. Culms 2—10(—15) m tall including the synflo-
supported by NSF Grant DLB-9806877 to LGC.
rescences; internodes solid. Leaves distichous;
sheaths longer than the internodes, tightly enclos¬
Literature Cited
ing the internodes, persistent; collar pilose on
Barker, N. P. 1997. The relationships of Amphipogon, Ely-
young leaves with rudimentary blades; ligules pi¬
trophorus and Cyperochloa (Poaceae) as suggested by
lose; blades (0.4-)1.5-2 m long, leathery, articu¬
r/>cL sequence data. Telopea 7: 205—213.
lated with the sheaths, disarticulating up to the Caro, J. A. 1982. Sinopsis taxonbmica de las granuneas
middle of the culms, not pseudopetiolate, the mid¬ argentinas. Dominguezia 4: 1—51.
rib 0.5—1.5 cm wide, usually conspicuous. Synflo- Clayton, W. I). & S. A. Renvoize. 1986. Genera Gramin-
um, Grasses of the World. Her Majesty’s Stationery Of¬
rescences paniculate, the pistillate plumose. Pistil¬
fice, London.
late spikelets with 2 florets, disarticulating above Conert, H. J. 1987. Current concepts in the systematics
the glumes and between the florets; glumes un¬ of the Arundinoideae. Pp. 239—250 in T. R. Soderstrom,
equal, 1- to 3-nerved, the upper glume longer and K. W. Hilu, C. S. Campbell & M. E. Barkworth, Grass
Systematics and Evolution. Smithsonian Institution
firmer than the lower glume, exceeding the florets;
Press, Washington, D.C.
callus linear, glabrous; lemmas long silky pilose
Dallwitz, M. J., T. A. Paine & E. J. Zurcher. 1999 onward.
above, the apex elongated and narrowed, not User’s Guide to the DELTA Editor. http://biodiversity.
awned; lodicules 2. free, truncate, membranous, uno.edu/delta/
sometimes bearing a few long hairs, faintly 2- or 3- Grass Phylogeny Working Group. 2000. A phylogeny of
the grass family (Poaceae) as inferred from eight char¬
nerved; stamens 2, rudimentary; styles 2, free;
acter sets. Pp. 3-7 in S. W. L. Jacobs & J. Everett,
rachilla extension absent. Staminate spikelets with Grasses: Systematics and Evolution. CS1RO Publishing,
2 to 4 florets, disarticulating below the distalmost Collingwood, Victoria.
floret, glumes and lowermost floret remaining at¬ -. 2001. Phylogeny and subfamilial classification of
the grasses (Poaceae). Ann. Missouri Bot. Gard. 88:
tached; glumes subequal, membranous, 1 -nerved;
373-457.
lemmas membranous, glabrous or sparsely short pi¬ Hitchcock, A. S. 1914. A Text-Book of Grasses. MacMil¬
lose, (0)1 (3)-nerved; lodicules 2, free, faintly lan, New York.
nerved, truncate; stamens 2; ovary abortive. Cary- Hsiao, C., S. W. L. Jacobs, N. P. Barker & N. J. Chatterton.
352 Novon
1998. A molecular phytogeny of the subfamily Arun- tographia Synoptica. Enumeratio Graminum. J. G. Cot-
dinoideae (Poaceae) based on sequence of rDNA. Aus¬ tae, Stuttgart and Tubingen.
tral. Syst. Hot. 11: 41-52. Renvoize, S. A. 1981. The subfamily Arundinoideae and
-.-, IN. J. Chatterton & K. H. Asay. 1999. A its position in relation to a general classification of the
molecular phylogeny of the grass family (Poaceae) Gramineae. Kew Bull. 36: 85-102.
based on the sequences of nuclear ribosomal DNA Sanchez-Ken, J. G. & E. G. Clark. 2000. Overview of the
subfamily Centothecoideae (Poaceae). Arner. J. Bot.
(ITS). Austral. Syst. Hot. 11: 667-668.
Suppl. 87: 163. [Abstract.]
Kalbola, II. & S. A. Renvoize. 1994. One or more species
Watson, E. & M. J. Dallwitz. 1992. The Grass Genera ol
of Gynerium? (Poaceae). Kew Bull. 49: 305-320.
the World. C.A.R. International, Wallingford, Oxon,
Kunth, C. S. 1833. Enumeratio Plantarum. Vol. I Agros- England.