Anthurium rzedowskii Croat, sp.
Mexico. Guerrero: along road between Hwy. 95 near Milpillas and 3.5 mi west of junction with road to Chichihuaico, elev. 2,425 m, Croat 45520 (MO-2690028-31, holotype; Live at MO).
Planta epiphytica aut terresiris; caudex ad 30 cm longus, 2-3 cm diam.; lamina ovata aut ovata-triangularis, 24-64 cm longa, 15-46 cm lata, basi cordata coreacea, nervo collectivo plerumque e nervo basi primo aut interdum e nervo laterali exorienti, saepc nervo colleclivo secondario; inflorescentia effusa-erecta, foliis breviora; spatha viridis, 3.5-13 cm longa, 1.6-6 cm lata; spadix viridis, 3.8-13 cm longus; baccae im-malurae purpureae.
Epiphytic or terrestrial; stems green, less than 30 cm long, 2-3 cm diam.; leaf scars 1.5 cm wide; roots 5-6 mm diam., pale green to tan, descending; cataphylls subcoriaceous, 6-10 cm long, pale green, acute at apex with slender subapical apiculum to 3 mm long, drying dark brown, the apex remaining intact, splitting at base and persisting.
LEAVES with petioles erect to spreading, subte-reie or flattened adaxially, rarely with single abaxial rib; geniculum 2-2.5 cm long; blades ovate to ovate-triangular, acuminate at apex, shallowly to deeply lobed at base, 24-64 cm long, 15-46 cm wide, broadest below middle or near point of petiole attachment; anterior lobe 16-49 cm long, the margins convex; posterior lobes 7-20 cm long; sinus arcuate to parabolic, frequently with decurrent petiole; upper surface semiglossy, lower surface matte to semiglossy; the midrib flat to weakly, convexly raised above, narrowing and sunken at apex, prominently raised below; basal veins 3-7 pairs, the first free, the remainder coalesced 1-3.5 cm, the fourth to sixth sometimes coalesced up to 6 cm, raised above, prominulous below; primary lateral veins 7-17 per side, departing midrib at 35°-65° angle, weakly raised in valleys or sunken above, raised below, straight to weakly curving to collective vein; inlerpri-mary veins flat above, prominulous below; collective vein 1.5-3.5 mm from the margin, arising from the first basal vein, frequently with a secondary collective vein 0.4-1 mm from the margin, arising from the second basal vein and extending irregularly to apex or running to margin in apical quarter of blade, sunken above, raised below.
INFLORESCENCE erect-spreading, shorter than leaves; peduncle 19-56 cm
long, 4-7 mm diam., terete; spathe moderately thick, medium green (B & K Yellow-green
7/7.5), narrowly to broadly ovate, 3.5-13 cm long, 1.6-6 cm wide, abruptly acuminate
at apex, rounded at base, inserted at 80°-90° angle on peduncle;
stipe 9 mm long in front, 5 mm long in back; spadix green (B & K Yellow-green 7/7.5), 3.8-13 cm long, 8-10 mm diam. at base, 6-9 mm diam. at apex; the flowers rhombic to sub-4-lobed, ca. 2.3 mm long, ca. 2.9 mm wide, the margin ± obscure, straight to weakly sigmoid; 6-7 flowers visible in the principal spiral, 8-9 flowers visible in the alternate spiral; tepals matte, densely and minutely papillate, small droplets on tepals as stamens emerge, lateral tepals ca. 2.1 mm wide, the inner margin broadly rounded; pistils weakly emergent before stamens emerge, green, darker than tepals and conspicuously punctate; stigma linear, ca. 0.5 mm long, nearly obscure; stamens emerging from the base in a rapid sequence, the lateral stamens emerging first, quickly followed by alternates; the anthers creamy white usuallynot opening until the third or fourth stamens emerge, exserted briefly on translucent filament, held inward over pistil, ca. 1.1 mm long, ca. 1.2 mm wide; thecae oblong-ovoid, slightly divaricate; pollen creamy white, fading to white.
INFRUCTESCENCE pendent; spathe persisting; immature berries purplish, round at apex, mature berries not seen. Figs. 162 and 164.
Anthurium rzedowskii is known only from Mexico in the states of Guerrero,
Oaxaca, and Chiapas at elevations of 1,400 to 2,900 m in "bosque pino-encino."
It is named in honor of Dr. J. Rzedowski of the Institute Polytechnica in Mexico
City, one of the first collectors of the species.
The species is a member of section Belolonichium and is characterized by its coriaceous, ovate blades with the collective vein usually arising from the first basal vein or sometimes arising from one of the primary lateral veins and frequently with a secondary collective vein extending irregularly along the margin to the apex or almost to the apex. It is probably most similar to A. subcordatum in having coriaceous leaf blades with the collective vein arising from the first basal vein or one of the primary lateral veins, and in frequently having a secondary collective vein arising from the second basal vein and extending along the margin to the apex or almost to the apex. Anthurium subcordatum differs in having truncate to subcordate leaf blades, a violet-purple spadix;
it occurs in Guatemala, El Salvador, and Honduras.