Anthurium nelsonii Croat,sp. nov.
TYPE: Mexico. Oaxaca: Reyes (Rcyes Ella, NNW of city of Oaxaca)
2,500-3,466 m; E. W. Nelson 1758 (US-358640, holotype).
Planta terrestris, ca. 1 m alia; caudex ca. 4 cm diam.; petiolus 29-48 cm longus,
sulcatus late aculeque; lamina ovata aut triangularis-ovata, 30-57 cm longa,
22-56 cm lata, basi cordata profunde, in pagina inferiore albida hebetataque;
inflorescentia effusa-pendula; pedunculus 30-43 cm longus; spatha viridis, 10-13
cm longa, 1.5-3 cm lata; spadix purpureus, 6.5-15 cm longus; baccae obovoideae.
Terrestrial, less than 1 m tall; stems ca. 4 cm diam.; roots 3 mm diam.; tan,
smooth to woolly pubescent (dry); cataphylls ca. 8 cm long, drying tan to reddish-brown,
weathering to moderately thin fibers.
LEAVES with petioles 29-18 cm long, 6-8 mm diam., sharply and broadly
sulcate adaxially; the geniculum 1-1.5 cm long; blades broadly ovate to ovate-triangular,
30-57 cm long, 22-56 cm wide, broadest at base, acute to narrowly rounded and
apiculate at apex, deeply lobed at base, the margin sinuate and undulate; anterior
lobe 25-45 cm long; posterior lobes 11.5-25 cm long from apex of sinus to the
outermost point; the sinus arcuate or arcuate with petiole decurrent; upper
surface semiglossy, lower surface matte, often whitish with glistening translucent
circular cells scattered in the epidermis (visible at high magnification on
dried leaves); midrib convexly raised above; the basal veins 5-9, all except
the first and second (third) coalesced 5-11.5 cm, raised on both surfaces, drying
darker than the surface; posterior ribs broadly arcuate, naked most their length;
primary lateral veins 5-9 per side, almost straight or gradually curved upward,
arcuate-ascending near margin and joining margin, raised on both surfaces; collective
vein arising from one of the lowermost primary lateral veins (rarely as low
as the first basal vein), 3-7 mm from margin, weakly raised on both surfaces.
INFLORESCENCE spreading-pendent (?); peduncle 30-43 cm long, 3-5 mm
diam., terete, shorter to longer than petioles; spathe subcoriaceous, green,
lanceolate to ovate-lanceolate, 10-13 cm long, 1.5-3 cm wide, broadest just
above base, narrowly acuminate at apex, rounded to subcordate at base, inserted
at ca. 45° angle on peduncle; the stipe 3-25 mm long in back, 1-15 mm long
in front, 3-4 mm diam.; the spadix violet-purple, 6.5-15 cm long, 6-9 mm diam.
at base, 4-5 mm diam. at apex, sometimes curved; the flowers rhombic, 3.6-4.7
mm long, 2.6-3.9 mm wide (dry), the sides scarcely to jaggedly sigmoid; 6-8
flowers visible in the principal spiral, 4-6 flowers visible in the alternate
spiral; tepals matte, very minutely papillate, lateral le-pals 2.7-3 mm wide,
the inner margin broadly rounded; pistils not emergent; stigma oblong, 1 mm
long; stamens emerging from the base in a moderately slow progression; the anthers
held in a close cluster completely obscuring the pistil, ca. 1 mm long, ca.
1.4 mm wide; thecae narrowly
ovate, scarcely divaricate; pollen not seen.
INFRUCTESCENCE pendent, berries often developing only in the basal one half or one third; spathe persistent: spadix ca. 20 cm long, 3 cm diam.; berries obovoid, truncate to broadly rounded and scurfy, 10-13 mm long, 9-10 mm diam.; pericarp moderately thick, leathery at apex, small raphide cells, very dense in lower three quarters of berry; seeds 1-2, ± lens-shaped, brown, considerably flattened, raphide cells sparse and minute, 9-13 mm long, 7-9 mm wide, 3-4 mm thick, weakly depressed at apex, with a sticky, gelatinous appendage sometimes as large as seed. Figs. 117 and 118.
Anthurium nelsonii is endemic to Mexico, occurring in the State ofOaxaca in the arid region north northeast of the city of Oaxaca between latitudes 17° 10'N and 18°N at elevations of 1,000 to 2,500 m. The principal vegetation types of the region are "selva baja caducifolia" and "bosque pino-encino." The species is named in honor of the first collector, E. W. Nelson, who made the first collections in 1894. The collections have in part been confused with A. andicola, a species occurring in wetter parts of northern Oaxaca. Anthurium nelsonii is a member of section Belolonchium and is distinguished by its broadly ovate-triangular blade with well developed posterior lobes and a broad sinus and by its sharply and broadly sulcate petiole. The most characteristic feature and the principal feature by which it is distinguished from A. andicola is its matte, often whitish lower blade surface. The latter species is semiglossy on the lower surface.
Mexico. Oaxaca: no other location, Conzatii 1724 (US); Mirador, Ernest 2500 (US); Oaxaca City, Nelson 1758 (US); Santa Catarina Canon, Conzatii & Gon-zaiez U 80 (GH); vicinity Telixtlahuaca, Delgadillo 225 (MEXU); Tomellin Canon, Rose & Rose 11351 (NY, US).