PROVISIONAL SECTIONAL PLACEMENT OF ANTHURIUM SPECIES OF MEXICO AND MIDDLE AMERICA*

Sectional classification of Central American Anthurium

Key to Anthurium species of Mexico and Middle America

Provisional sectional placement of Anthurium species of Mexico and Middle America

la. Leaf blades prominently 3-lobed or palmatifid to palmatisect.

2a. Leaf blades with the lobes united at the base.

3a. Leaf blades with three lobes (the lateral or posterior lobes often smaller than the central lobe)

Section Semaeophyllium Schott
A. subsignatum Schott
A. tilaranense Standl.

3b. Leaf blades with five or more lobes

Section Schizoplacium Schott
A. pedatoradiatum Schott
A. pedatoradiatum ssp. helleborifolium (Schott) Croat
A. podophyllum (Cham. & Stiletto.) Kunth

2b. Leaf blades with the lobes free to the base.

Section Dactylophyllium Schott
A. clavigerum Poepp.
A. kunthii Poepp.
A. pentaphyllum (Aubl.) G. Don var. bombacifolium (Schott) Madison
A. trisectum Sodiro

1b. Leaf blades entire or nearly so, sometimes with the anterior lobe markedly constricted at the base but never distinctly 3-lobed.

4a. Leaf blades conspicuously dark glandular-punctate at least on the lower surface.

5a. Leaf blades cordate, hastate, or otherwise with usually definite posterior lobes; most basal veins usually merging with the margin of the blade proximal to the middle of the blade

Section Belolonchium Schott (Anthurium verapazense alliance)
A. chiapasense Standl.
A. chiapasense ssp. tiaxiacense (Matuda) Croat
A. longipeltatum Matuda
A. lucens Standl. ex Yuncker
A. riograndicolum Matuda *
A. verapazense Engl.

5b. Leaf blades acute to obtuse or subcordate at base with usually only a single collective vein extending along the margin to the apex (Sections Tetraspermium and Porphyrochitonium) or with several basal veins prominently arcuate-ascending to the apex with many close, parallel primary lateral veins extending between all the basal veins giving the blade the appearance of a mclastomalaccous leaf blade (Section Digitinervium).

6a. Leaf blades with several pairs of basal veins sharply arcuate-ascending, extending to or almost to the apex; primary lateral veins numerous, distinct, parallel, and extending more or less straight between all the basal veins, giving the leaf blade the appearance of a melastomataceous blade; pistils often prominently exserted and quadrangular; number of ovules and seeds per locule unknown

Section Digitinervium Sodiro
A. lentii Croat & Baker

6b. Leaf blades with usually no more than one pair of basal veins (usually merely the collective vein) extending along the margin to the apex; primary lateral veins usually not numerous or closely parallel; pistils not quadrangular; ovules and seeds usually two or more per locule.

7a. Plants mostly scandent; stems slender, mostly less than 6 mm diam.; internodes somewhat elongate; acute at apex

Section Tetraspermium Schott
A. scandens (Aubl.) Engl.
A. scandens ssp. pusillum Sheffer
A. tonduzii Engl.
A. trinerve Miq.

7b. Plants usually more or less cacspitose, at least lacking slender scandcnl stems; stems usually .more than 1 cm diam.; berries often more or less truncate and indented at the apex.

Section Porphyrochitonium Schott
A. acutangulum Engl. '
A. alatipedunculatum Croat & Baker
A. austinsmithii Croat & Baker
A. bakeri Hook. f.
A. durandii Engl.
A. friedrichsthalii Schott
A. hacumense Engl.
A. lancifolium Schott
A. louisii Croat & Baker
A. paludosum Engl.
A. ramonense Engl.
A. scherzerianum Schott
A. utleyi Croat & Baker
A. wendlingeri G. M. Barroso

4b. Leaf blades epunctate or at least not conspicuously dark glandular-punctate.

8a. Petioles D-shaped in cross-section or broadly channelled with more or less acute lateral margins

Section Belolonchium Schott (Anthurium andicola alliance)
A. andicola Liebm.
A. berriozabalense Matuda
A. cerrobaulense Matuda
A. chamulense Matuda
A. chamulense ssp. oaxacanum Croat
A. cordatotriangulum Matuda
A. cotobrusii Croat & Baker
A. montanum Hemsl.
A. nakamurae Matuda
A. nelsonii Croat
A. parvispathum Hemsl.
A. retiferum Standl. & Steyerm.
A. rionegrense Matuda
A. rzedowskii Croat
A. seleri Engl.
A. subcordatum Schott
A. subcordatum ssp. chlorocardium (Standl. & L. 0.Wms.) Croat
A. subovatum Matuda
A. titanium Standl. & Steyerm.

8b. Petioles usually terete or subterete in cross-section often narrowly channelled but with the margins rounded; sometimes square, triangular, trapezoidal, or otherwise, but not usually D-shaped.

9a. Vernation of leaf blades involute (i.e., with both margins rolled inward toward the midrib in bud); plants frequently with a "bird's-nest" habit, i.e., short stems and rosulate leaves; blades often thick, frequently more or less oblanceolate or obovate to elliptic; the primary lateral veins (at least the lower ones) joining the margins

Section Pachyneurium Schott
A. acutifolium ssp. acutifolium Engl.
A. brenesii Croat & Baker
A. consobrinum Schott
A. cubense Engl.
A. cuneatissimum (Engl.) Croat
A. cuspidatum Mast.
A. eximium Engl.
A. fatoense K.Krause
A. halmoorei Croat
A. machetioides Matuda
A. michelii Guillaumin
A. nizandense Matuda
A. oerstedianum Schott
A. prolatum Croat & Baker
A. protensum Schott
A. purpureospathum Croat
A. ranchoanum Engl.
A. salvadorense Croat
A. salviniae Hemsl.
A. schlechtendalii ssp. schlechtendalii Kunth
A. schlechtendalii ssp. jimenezii (Matuda) Croat
A. schottianum Croat & Baker
A. seibertii Croat & Baker
A. spathiphyllum N. E. Brown
A. spectabile Schott
A. standleyi Croat & Baker
A. upalaense Croat & Baker
A. validifolium K. Krause
A. watermaliense Hort. ex L. H. Bailey

9b. Vernation of leaf blades supervolulc (i.e., with one margin rolled inward toward the midrib but with the alternate margin rolled around the midrib and then rolled up opposite margin, giving the "cut-away" view a cochleate appearance); plants usually lacking a bird's-nest habit; leaves various; the primary lateral veins frequently joining into a collective vein before reaching the margin. '

lOa. Stems scandent and wiry; internodes elongate, usually less than 3 mm thick, with numerous, short adventitious roots scattered along their length; flowering branches bearing one to six leaves; 1-ribbed cataphylls lacking

Section Polyphyllium Engl.
A. clidemioides Standl.
A. flexile Schott
A. flexile ssp. muelleri (Macbr.) Croat & Baker

lOb. Stems short or scandent but not slender and wiry; internodes short or long but not slender and wiry, usually more than 8 mm diam.; the adventitious roots restricted to the nodes; flowering branches bearing a single leaf (branches arc short and do not appear like branches); 1-ribbed cataphylls present and usually conspicuous.

11 a. Roots white, bearing velamen; blades thin, narrowly oblanceolate, the primary lateral veins numerous and scarcely more prominent than the interprimary veins,* stems rarely more than 1 cm diam. with persistent reddish-brown, intact cataphylls; spadix with no more than three flowers visible per spiral (from any angle); chromosome numbers In = 10 or 20.

Section Leptanthurium Schott
A. gracile (Rudge) Lindl.

llb. Roots usually greenish, lacking velamen; blades various, usually with the primary lateral veins conspicuously more prominent than the interprimary veins; stems various; cataphylls usually weathering (except section Calomystrium with cordate blades); number of flowers per spiral various but usually more than three per spiral.

12a. Leaf blades velvety, usually metallic green or blackish-green in color; the epidermal cells papillate or otherwise elevated; petioles frequentlymribbed; B-chromosomes present

Section Cardiolonchium Schott
A. clarinervium Matuda
A. leuconeurum Lem.
A. lezamae Matuda

12b. Leaf blades not velvety, usually smooth and semiglossy to glossy; the epidermal cells flat, not papillate or raised; petioles various but not commonly ribbed; B-chromosomes lacking.

13a. Stems bearing conspicuous, thick, intact, persistent, reddish-brown cataphylls; leaf blades usually thick; the minor veins usually not prominently raised; the upper blade surface usually with linear raphide cells visible; spadix often colored, often sweetly scented;
spathe usually thick, often broad

Section Calomystrium Schott
A. armeniense Croat
A. beltianum Standl. & L. 0. Wms.
A. clavatum Croat & Baker
A. formosum Schott
A. hoffmannii Schott
A. huixtlense Matuda
A. monteverdense Croat & Baker
A. obtusilobum Croat & Baker
A. ravenii Croat & Baker

13b. Stems usually with cataphylls deciduous or weathering into a mass t of fibers (sometimes persisting intact, as in A. eximium); leaf blades thick or thin; the minor veins conspicuous or not; the upper surface usually lacking raphide cells; spadix various, less frequently scented; spathe various, often lanceolate. 14a. Leaf blades much longer than broad, oblong to linear (rarely ovate but then thin, veiny, and weakly bullate as in A. davidsoniae).

15a. Stems elongate, erect to scandent 7-20 mm diam. 16a. Leaf blades thin, veiny, and weakly bullate; the reticulate veins often conspicuous; spathe and spadix usually green or greenish-yellow; spadices commonly cylindrical; berries commonly pale green.

Section Xialophyllium Schott (A. microspadix alliance)
A. davidsoniae Standl.
A. microspadix Schott
A. pallens Schott

16b. Leaf blades usually coriaceous or thickly chartaceous, smooth; the reticulate veins usually not conspicuous; spathe and spadix various or not known.

Section Xialophyllium Schott (A. caucanum alliance)
* Section Urospadix centered in Brazil and apparently not represented in Central America have leaf blades that also have this characteristic.

A. angustispadix Croat & Baker
A. burgeri Croat & Baker
A. carnosum Croat & Baker
A. interruptum Sodiro
A. tenerum Engl.
A. testaceum Croat & Baker

15b. Stems short; the internodes short; stems mostly less than 10 mm diam.

17a. Pistils prominently exserted long before anthesis and many times longer than the stamens when they appear.

Section Oxycarpium Schott
A. pittieri Engl.
A. pittieri var. fogdenii Croat

17b. Pistils not prominently exserted long before anthesis, about as long or no more than a few times longer than stamens......

Section Xialophyllium Schott
A. burgeri Croat & Baker (usually with longer stems)

14b. Leaf blades not much longer than broad (or at least not oblong or linear), mostly more or less ovate with posterior lobes.

18a. Blades moderately thin, often conspicuously veiny or ð' even bullate; anterior lobe usually with numerous, close, more or less parallel veins; berries frequently green

Section Polyneurium Schott
A. caperatum Croat & Baker
A. panduriforme Schott
A. williamsii K. Krause

18b. Blades coriaceous or nearly so, usually smooth and not noticeably veiny or bullate; anterior lobe lacking numerous close parallel veins

Section Belolonchium Schott
A. brownii Mast.
A. cerropelonense Matuda
A. concinnatum Schott
A. lancetillense Croat
A. ochranthum C. Koch
A. ovandense Matuda
A. pluricostatum Croat & Baker
A. silvigaudens Standl. & Steyerm.
A. umbrosum Liebm.
A. yetlense Matuda