You are here
Araceae
Dieffenbachia horichii Croat & Grayum
SUMMARY
Stout herb, 1-1.5(2) m tall; sap white, copious, foetid, caustic; stem erect on younger parts, to 1.2 m long and reclining on older parts, internodes 1- 3 cm long, 4-6 cm diam., semiglossy to glossy, dark green to medium green; petioles 8-33 cm long (av- eraging 18.7 cm long), weakly glossy, sheathing nearly or completely throughout; sheath medium green streaked with yellow-green, margins involute, the tip free-ending and irlequilaterally rounded-auriculate (auricle sometimes extending up to 1.5 cm beyond blade); unsheathed portion lacking or to 1.2 cm long (rarely to 6 cm long), obtusely somewhat flattened in cross section; blades narrowly to broadly elliptic to ovate-elliptic, 26-60 x 9-30 cm (averaging 45 x 19 cm), 1.9-3.4 times longer than wide (averaging 2.5 times longer), 1.7-4 times longer than petiole, slightly inequilateral, one side 0.5-1.2 cm wider than the other side, subcoriaceous to coriaceous, somewhat bicolorous, acuminate at apex, + equilateral and obtuse to rounded (rarely acute or narrowly rounded) at base, margins weakly undulate; upper surface dark green, semi- glossy to highly glossy, drying dark gray-green to dark yellow-brown; lower surface weakly glossy to matte, moderately paler, drying yellow-brown to yellowish green; midrib broadly and shallowly sunken to flat-sunken above, 5-20 mm diam., con- vex and bluntly low-triangular below, drying light brown to dark brown paler than surface below; primary lateral veins 14 to 21 per side, departing mid- rib at a mostly 30°-40° angle above middle, often 70°-90°, often arising at an acute angle, spreading to the margins, broadly curved toward apex, even- tually merging at margins, weakly sunken above, weakly convex below, drying brownish and darker than surface below; the interprimary veins usually darker than surface, 1 between each pair of primary lateral veins; minor veins visible, slightly darker than surface, drying moderately obscure on lower surface. INFLORESCENCES 3 to 6 per axil; peduncle 8.5-19 cm long (averaging 13.5 cm), 3-6 mm diam., drying striate; spathe 14.5-32.5 cm long, 4-5.5 cm diam. (averaging 20.8 cm long), 2.5-4 cm diam. at constriction, 0.9-2.3 times longer than the peduncle (averaging 1.5 times longer than the peduncle), gradually long-tapered toward apex from midway, light green to medium green throughout; spathe tube 3 x 2.3 cm diam. when furled (flattening 4.0-5.5 cm wide), the constricted area flattening 2.5-4.0 cm wide; spathe blade 2.5- 4 cm wide at anthesis; spadix 13-27 cm long (averaging 17.4 c m long); free portion 10-13.5 cm long; pistillate portion to (6.5)8-10.8 cm long (averaging 8.3 c m long), 8-17 mm wide, drying 8 mm diam.; fertile staminate portion 8. 3-12 cm long, crearm-coloured, moderately tapered toward apex and weakly tapered toward base, 7-12 mm diam. midway; mostly sterile intermediate segment 1 .7--3.7 cm long, with a few scattered staminodia throughout; pistils 4.-3 to 69, irregularly scattered, nearly contiguouse .-3 to 4(6 to 7) dispersed across spadix width separated from one another by up to 4 times their width; ovary depressed-globoxe 2 mm long, yellow-green; stigma cushion-shaped, 2.8-3.4 mm diam., about twice as wide ax thick and usually broader than the pistil at anthesix, yellowish; staminodia white, 3 to 5 per pistil, 3-4 mm long, free or briefly united at base; synandria 1.6-3.0 mm diam., subrounded, depressed medially at apex, drying orange-brown. INFRUCTESCENCE 19-24 cm long; spathe orange outside; spadix 8-15 cm long; berries red, subglobose, ovoid to ellipsoid, 7- 10 mm long.