Philodendron dwyeri Croat, sp. nov.
TYPE: Belize. Cayo: Macal (Macaw) River, Guacamallo Bridge, 16E52'N, 89E05'W, Dwyer & Liesner 12334 (holotype, MO--2179389). Figure 155.
Planta epiphytica aut epilithica; succus albus; internodia longior quam lata, ca. 2 cm diam.; cataphylla probobiliter decidua; petiolus teres, 36.5 cm longus, 4 mm diam., leniter longior quam laminae; lamina ovata, 33 cm longa, 21 cm lata, in sicco cana-viridis supra, flaviviridis infra; sinus 7--8 cm profundus; inflorescentia 1; pedunculus 7 cm longus, 5 mm diam.; spatha 9.5 cm longa, omnino viridis, in sicco intus rubrobrunnea; pistilla 7--8-locularia; loculi 1-ovulati.
Epiphytic or epilithic; sap white; internodes slightly longer than broad, ca. 2 cm diam., semiglossy, epidermis light brown, drying conspicuously wrinkled and folded into sharp, irregular ridges; roots 3--4 mm diam, drying reddish brown with prominent ridges, semiglossy, with thin broad scales; cataphylls not seen, probably deciduous; petioles 36.5 cm long, 4 mm diam., terete; blades ovate, acute at apex (the acumen more or less inrolled, 5 mm long), cordate at base, 33 cm long, 21 cm wide (1.5 times longer than wide), (0.9 times the petiole length), slightly shorter petioles, margins sinuate, upper surface drying gray-green, lower surface paler, drying yellow-green; anterior lobe 24.6 cm long, 21 cm wide (1.2 times longer than wide); posterior lobes 9 cm long, 9.5 cm wide, rounded, directed toward base; sinus 7-8 cm deep; midrib convex and concolorous above, convex and paler, drying yellowish, closely fissured and minutely warty below; basal veins 3 per side, with 1 free to base, 1 coalesced, second and third veins coalesced 1.9 cm; posterior rib not naked; primary lateral veins 5 per side, departing midrib at a 50--60(75)E angle; minor veins moderately distinct, arising from both the midrib and primary lateral veins. INFLORESCENCES 1 per axil; peduncle 7 cm long, 5 mm diam.; spathe 9.5 cm long (1.3 times longer than peduncle), visibly constricted above the tube, elliptic and to 5.5 cm wide when flattened, green throughout, green, drying reddish brown within; spathe tube ca. 4 cm long; spadix sessile; 7.2 cm long, broadest more or less uniform throughout; pistillate portion cylindrical, 1.3 cm long, 1 cm diam.; staminate portion 6 cm long; fertile staminate portion cylindrical, 1 cm diam., broader than the pistillate portion, sterile staminate portion not detectable; pistils 1.1 mm long, 0.6 mm diam.; ovary 7--8-locular, 0.6 mm diam., with basal placentation; ovules 1 per locule, 0.1 mm long, more or less equal in length to funicle, style 0.6--0.8 mm diam., similar to style type D; style apex more or less flat, with style boss; stigma subdiscoid, unlobed, 0.7--1.1 mm diam., 0.1 mm high, covering interior faces of stylar funnel; the androecium truncate, margins 4-6-sided; thecae oblong, very elongated, 0.2 mm wide.
Flowering in Philodendron dwyeri is documented by a single post-anthesis collection from January, early in the dry season.
Philodendron dwyeri is endemic to Belize, known only from the type collection in Cayo District of Belize at the Macal (Macaw) River near the Guacamallo Bridge at less than 500 m elevation.
Philodendron dwyeri is a member of P. sect. Calostigma subsect. Macrobelium ser. Macrobelium. This species is characterized by having internodes longer than broad, white sap, terete petioles (slightly longer than blades), ovate blades drying gray-green above and much paler gray-green below with a very narrow sinus, solitary inflorescences with a green spathe, and ovaries with seven to eight locules and one ovule per locule.
Philodendron dwyeri is probably most easily confused with P. breedlovei from adjacent Chiapas, which is also a vine with blades of similar size and shape. That species differs, however, in having blades which dry dark yellow-brown with a more or less V-shaped sinus and ovaries with about 20 ovules per locule.
Additional specimen examined.
BELIZE. Cayo: S of Guacamallo Bridge, Whitefoord 2837A (BM).