Philodendron basii Matuda,
Anales Inst. Biol. Univ. Nac. Méxic. 32: 153, Fig. 8. 1961. TYPE: Mexico. Mexico: Barranca de Malinaltenango, NE (published as SE) of Zacualpan, 1200 m, 18E43'N, 99E36'W, Matuda 37244 (holotype, MEXU). Figures 76, 81--84.
Almost always terrestrial, or trailing over rocks; stem green, stout, succulent, leaf scars conspicuous, 2--4 cm long, 4--5 cm wide; internodes 1--4 cm long, 2.5--7 cm diam., broader than long, drying olive-green, epidermis peeling, light brownish, roots long, 5 mm diam., light reddish tan; cataphylls 20--28 cm long, weakly to sharply 2-ribbed, medium green with darker ribsand dark green speckles in lower one-half of cataphyll, drying tannish, persisting intact, eventually deciduous; petioles 22--70 cm long, 8--15 mm diam., terete, medium green, surface dark striate; blades ovate-cordate, drying moderately thin, weakly bicolorous, semiglossy, acute at apex, cordate at base, 16--56 cm long, 9--38 cm wide (1.5--1.8 times longer than wide), (0.7--0.9 times the petiole length), broadest at or above middle; upper surface medium green, weakly glossy, drying medium yellow-brown;, lower surface slightly paler, semiglossy, drying yellow-green to yellow-brown; margins sinuate or weakly undulate; anterior lobe 35--48 cm long, 37.5--46 cm wide (2.5--8.5 times longer than posterior lobes); posterior lobes 4--19 cm long, 18--23 cm wide, directed inward, rounded to obtuse at apex; sinus spathulate, 10--13 cm deep; midrib weakly sunken to flat, heavily dark green striate, paler than surface above, convex, sparsely dark-lineate, paler than surface below; basal veins 3--6 per side, with 1 pair free to base, the third through fifth coalesced 3--3.5(4) cm; posterior rib naked for 1--2.5 cm; primary lateral veins 4--7 per side, departing midrib ata 40--60E angle, more or less straight to the margins, sunken and paler than surface above, convex and paler than surface below; interprimary veins sunken and concolorous above, flat and darker than surface below; branches of primary lateral veins more or less ruffled-sunken and concolorous above, raised and paler than surface below; minor veins predominately arising from the primary lateral veins, those arising from the midrib seem to disappear soon after leaving the midrib. INFLORESCENCES probably 1 per axil; peduncle 7--8 cm long, 7--8 mm diam., green; spathe 12.6--13.7 cm long, (1.7--1.8 times longer than peduncle), apiculate at apex; spathe blade pale green or white, tinged red near base outside, 8 cm long, white tinged with red near base, pale-speckled inside; spathe tube ellipsoid, dark green outside, 6 cm long, 3 cm diam., maroon-red (B & K Red-Purple 10/3) inside, spadix sessile; tapered, 11.8--12 cm long, broadest at the base; pistillate portion cylindrical, 2.5--3.8 cm long, 1.5--1.9 cm diam. midway, slightly narrower on both ends; staminate portion 7.6--13 cm long; fertile staminate portion clavate, 9--15 mm diam. at base, 11--15 mm diam. at middle, 5--10 mm diam. ca. 1 cm from apex, broadest above the middle, narrower than the pistillate portion, broader than the sterile portion; sterile staminate portion narrower than the pistillate portion, 1--1.8 cm diam.; pistils 2.9--3.9(5.7) mm long, 1.4--2 mm diam.; ovary 4--6-locular, 2 mm long, 1.4 mm diam., with sub-basal placentation; ovules 4--6 per locule, 2--3-seriate, contained within transparent ovule sac, 0.3 mm long, equal in length to funicle, style similar to style type D; style apex rounded, with style boss and with depressions surrounding stylar canal exits; style boss narrow but pronounced; stigma slightly discoid to hemispheroid, 1.6--2.2 mm diam., 0.6--1.4 mm high, covering almost entire style apex; the androecium 4--6 sided; thecae oblong, 0.3 mm wide; sterile staminate flowers 4--6-sided, 1.7 mm long, 0.9--1.6 mm wide. JUVENILE leaves more or less sagittate at base.
Flowering in Philodendron basii is recorded during the early wet season with post-anthesis collections made during September and in January although too few collections overall have been seen.
Philodendron basii is endemic to Mexico, ranging from western Jalisco, south and east to the states of Colima, México and Guerrero, at 350 to 1200 m elevation in "Bosque Pino-Encino" and "Selva Baja Caducifolia." Matuda (1962) reported it from as low as 200 m elevation.
Philodendron basii is a member of P. sect. Calostigma subsect. Macrobelium ser. Pachycaulia. The species is characterized by its very stout, green, succulent stems which usually trail over rocks, weakly two-ribbed cataphylls which remain intact and are usually soon deciduous, long-petiolate, moderately thin, ovate cordate blades with a sinuate margin, and by the green spathes with the tube reddish-purple within.
Though Philodendron basii is not easily confused with any other species, it is ecologically very similar to P. warszewiczii, which also has thick, succulent, bare stems and occurs in very dry habitats. The latter is distinguished by its deeply dissected leaf blades. Matuda compared P. basii with P. smithii, to which it bears only a superficial resemblance. That species differs in having more slender internodes which are usually longer than broad, more narrowly ovate blades, and (usually) two inflorescences per axil with longer peduncles.
Though no specimens have been seen from Colima State in Mexico, Matuda (1962) reported having seen this species there.
Additional specimens examined.
MEXICO. Guerrero: km 337--338 beyond Acahuizotla on highway to Acapulco, 3000 ft., Moore 5100 (BH, CM); road to Xalpatlahuac between bridge over Río Omitlan and confluence of Río Papagayo with Río Omitlan, 850 m, Croat 45766 (MO). Jalisco: Highway 200, 10--13 km SE of El Tuito, valley of Río las Juntas, 250--330 m, McVaugh 25396 (MICH); ca. 6 mi. S of Tuito, 350 m, Croat 45442 (COL, MEXU, MO, US).