Philodendron clewellii Croat, sp. nov.
TYPE: Panama. Darién: middle slopes of W side of Cerro Pirre, cloud forest, 850--1050 m, 29 June 1988, Croat 68945 (holotype, MO-- 3589994; isotypes, F, K, PMA, US). Figure 102.
Planta epiphytica; internodia 12--18 cm longa, 3.5 cm diam., moderate nitida, fissurata; cataphylla mallia, acute 2-costata, decidua; petiolus subteres, obtuse complanatus adaxaliter, 24.5--53 cm longus, (2)7--14 mm diam.; lamina ovato-cordata, 30--59 cm longa, 20--45 cm lata, in sicco brunnea, nervis basalibus liberis (aut leniter coalatis); inflorescentia usque 6; pedunculus 3.5--16 cm longus, 3--6 mm diam.; spatha 4.5--7 cm longa; lamina spathae extus cremea, intus purpurascente cum margine albido; tubo spathae in superficiebus ambabus purpurascenti; pistilla 6(7)-locularia; loculi 2-ovulati.
Epiphytic; stem scandent, smooth, thick, moderately glossy; internodes moderately glossy, 12--18 cm long, 3.5 cm diam., longer than broad, medium green to dark gray-green, epidermis fissured weakly longitudinally; cataphylls 18--25 cm long, soft, sharply 2-ribbed, green, caducous; petioles 24.5--53 cm long, (2)7--14 mm diam., subterete, spongy, dark green, obtusely flattened adaxially, surface green or white streaked-lineate; blades broadly ovate-cordate, subcoriaceous, moderately bicolorous, acuminate at apex (the acumen 1-2 cm long), cordate at base, 30--59 cm long, 20--45 cm wide (1.25--1.83 times longer than wide), (0.95--1.65 times longer than petiole), upper surface dark green, drying brown, semiglossy, lower surface slightly paler, drying brown, sometimes red-brown or green-brown, semiglossy, paler; anterior lobe 26.7--42.2 cm long, 23--45 cm wide (2.36--3.95(5.28) times longer than posterior lobes); posterior lobes broadly rounded, often overlapping, 7--18 cm long, 12--21 cm wide, obtuse to rounded; sinus narrowly closed; midrib weakly raised to almost flat, purple-spotted, paler than surface above, convex, darker than surface below; basal veins 3--5 per side, all free to base (or weakly fused); posterior rib absent or to 1.5 cm long, not at all naked; primary lateral veins 4--7 per side, departing midrib at a 45--60E angle, straight to the margins, weakly sunken, concolorous above, raised below, secondary veins weakly visible; minor veins visible, sparse, discontinuous below, arising from both the midrib and primary lateral veins.
INFLORESCENCES to 6 per axil; peduncle 3.5--16 cm long, 3--6 mm diam., drying 2--4 mm diam., green, heavily red-striped; spathe 4.5--7 cm long, ((0.62)1.28--2.33 times longer than peduncle); spathe blade cream outside, purplish, with margins whitish inside; spathe tube purple outside, 2.5--3 cm long, 6--10 mm diam., purple inside; spadix sessile; clavate, 6 cm long; pistillate portion green, tapered toward the apex, 2.5 cm long, 6 mm diam. at apex, 7 mm diam. at middle, 8 mm wide at base; staminate portion 3.7 cm long; fertile staminate portion white, clavate, 7 mm diam. at base, 9 mm diam. at middle, 8 mm diam. ca. 1 cm from apex, broader than the pistillate or sterile portions; sterile staminate portion 7 mm diam.; pistils 1.6 mm long, 1.1 mm diam.; ovary 6(7)--locular, with sub-basal placentation; ovules 2 per locule, contained within translucent ovule sac, 0.2 mm long, equal in length to funicle, style similar to style type B; style apex concave; stigma discoid, unlobed, 0.6 mm diam., 0.1 mm high, covering interior faces of stylar funnel; the androecium truncate, 4--6-sided; thecae oblong to ellipical, 0.1--0.2 mm wide; sterile staminate flowers iregularily shaped, 2.1 mm long, 9 mm wide, the margins blunt. JUVENILE plants with internodes 5--6 cm long, 8 mm diam., dark green; petioles terete, sheathing to midway.
Flowering phenology in Philodendron clewellii is unclear because there are too few fertile collections. It has been collected in flower in December and post-anthesis in June, giving a hint of a bimodal flowering. Though Cerro Pirre is not markedly seasonal, these two months in general would mark extremes, with December being the general beginning of the dry season and June being the beginning of the rainy season in Panama.
Philodendron clewellii is endemic to Panama, known only from the Serranía de Pirre, from 850 to 1560 m elevation in Premontane wet forest.
Philodendron clewellii is a member of P. sect. Calostigma subsect. Oligocarpidium. The species is distinguished by its thick, smooth stems, usually long internodes, sharply two-ribbed, deciduous cataphylls, subterete petioles, ovate-cordate, dark brown drying blades with free or weakly fused basal veins and narrow, closed sinus with often overlapping posterior lobes, and especially by its clusters of up to six, small inflorescences per axil with long peduncles, and spathe purple on the outside of the tube and cream on the blade.In fertile condition, Philodendron clewellii does not resemble any other described species, but the leaf blades are similar to those of P. tysonii Croat. That species differs in having no more than three, much larger inflorescences at anthesis (to 12 cm or more long). In addition, the leaves of P. tysonii usually dry darker. In the blade shape and lack of a naked posterior rib, it is similar to P. grayumii Croat. That species differs in having generally more reddish brown blades with a broader sinus and much stouter peduncles.
The species is named in honor of Andrew Clewell who made several expeditions to Panama while working for Florida State University and who helped collect the type specimen.
Additional specimens examined.
PANAMA. Darién: Cerro Pirre region, 1000--1400 m, Gentry & Clewell 7028 (K, MO); Río Cana--Río Escucha Ruido, Croat 37831 (MO); ca. 12 km N of Alto de Nique, 1520--1560 m, Croat 37915 (F, MO); ca. 16 km N of Alto de Nique, 1530--1550 m, Croat 37946 (MO); middle slopes on W side, 800--1050 m, 7E56'N, 77E45'W, Croat 68957 (MO).