PHILODENDRON CRETOSUM

PROTOLOGUE: Philodendron cretosum , published in Annals of the Missouri Botanical Garden 84: 427 (1997).

Philodendron cretosum Croat & Grayum, sp. nov.

Planta epiphytica aut hemiepiphytica; internodia brevia, 1–3 cm diam.; succus calcareus, in sicco mox calcareus; cataphylla 23–42 cm longa, obtuse 1-costata, in sicco pallide flavibrunnea, persistentia ut fibrae pallidae; petiolus obtuse et late aut profunde et anguste sulcatus adaxialiter, 10.5–23.5 cm longus, 3–6 mm diam.; lamina linearis vel oblanceolata, 29–84.5 cm longa, 5–12 cm lata; inflorescentia 1–3; pedunculus (2.5)4–8.9 cm longus, ca. 10 mm diam.; spatha 9–13.5 cm longa; lamina spathae extus pallide viridi vel viridialba, intus viridialba; tubo spathae extus viridi, intus albo; pistilla 4-locularia; loculi cum 18–20-seminibus.

Type: Panama. Coclé: vicinity El Valle de Antón, at forested flat area near Finca Macarenita at La Mesa, 800 m, 8°36'N, 80°07'W, 6 July 1994, Croat & Zhu 76661 (holotype, MO-04619350-51; isotypes, AAU, B, CAS, CM, COL, CR, F, K, L, M, MEXU, NY, OOM, P, PMA, QCA, SEL, TEX, US, VEN). Figures 125–126, 144.

DISTRIBUTION: Costa Rica to Panama: Costa Rica, Panama.

SPECIES DESCRIPTION:

Epiphytic or hemiepiphytic; stem appressed-climbing, elongate, sap chalk-white; internodes short, 4–9 cm long on lower stems, short on flowering plants, 1–3 cm diam., as broad as long or slightly longer than broad, gray-green; roots drying dark brown, few per node; cataphylls thin, membranous, 23–42 cm long, bluntly 1-ribbed, green, drying pale yellowish brown, persisting as pale fibers; petioles 10.5–23.5 cm long, 3–6 mm diam., medium green, semiglossy, bluntly and broadly or deeply and narrowly sulcate adaxially, with adaxial margins obtuse or sometimes acute; blades linear to oblanceolate, chartaceous to weakly subcoriaceous, weakly bicolorous, drying greenish to yellowish brown on both surfaces, matte and paler below, acuminate to weakly acute at apex (the acumen apiculate), attenuate at base, 29–84.5 cm long, 5–12 cm wide (5.1–8.3 times longer than wide), (2.6–4.7 times longer than petiole), much longer than petioles, broadest in upper one-third; midrib prominently and narrowly sunken above, thicker than broad, bluntly acute, glossy and darker than surface below; basal veins lacking; primary lateral veins 6–9 per side, departing midrib at a 25–45° angle, straight to weakly arcuate to the margins, sunken above, convex below; interprimary veins sunken above, slightly raised below; minor veins arising from midrib only; tertiary veins visible, darker than surface below.

INFLORESCENCE:

INFLORESCENCES 1–3 per axil; peduncle (2.5)4–8.9 cm long, ca. 10 mm diam., drying 3–5 mm diam., shorter than petiole, subterete or irregularly angled, white-striate; spathe subcoriaceous, semiglossy, 9–13.5 cm long, (1.8–3.3 times longer than peduncle), moderately constricted midway or just below the middle, abruptly acuminate at apex; spathe blade lanceolate, pale green to greenish white outside, 5.5–8 cm long, greenish white inside; spathe tube ellipsoid, green, short white lineate outside, 3.5–5.5 cm long, 1.8–2 cm diam., white (at anthesis) inside; spadix stipitate to 5 mm long; 11–15 cm long; pistillate portion white to pale greenish, weakly ellipsoid, 3–3.5 cm long; staminate portion 4.5–7.8 cm long; fertile staminate portion white; sterile staminate portion 1.2 cm diam.; pistils 0.6–0.9 mm long, 3 mm diam., drying blackish; ovary 4-locular, with axile placentation; ovules ca. 20 per locule, 2–3-seriate, 0.3–0.4 mm long; funicle ca. 0.4 mm long, adnate to lower part of partition, style similar to style type D; style apex flat, with a small style boss; stigma hemispherical; the androecium oblong, 3–5-sided, 0.8–1.2 mm long, 0.4–0.6 mm diam. at apex; sterile staminate flowers irregularly 4–6-sided, 1.5–2.1 mm long, 0.7–1 mm wide. INFRUCTESCENCE 6 cm long, 2.5 cm diam.; seeds 18–20 per locule, obovoid to weakly ellipsoid, 0.8–1 mm long, 0.4–0.5 mm diam.

ECOLOGY:

Found in tropical wet forest and premontane rainforest life zones.

ETYMOLOGY:

From Latin cretosum, “full of chalk,” referring to the white chalky sap.

NOTES:

1. Philodendron cretosum is a member of Philodendron sect. Philodendron subsect. Canniphyllum. This species is recognized by its short internodes, white chalky sap (hence the name “cretosum,” meaning “full of chalk”), persistent, thin, pale cataphyll fibers, bluntly sulcate petioles much shorter than the blades, and especially its linear to oblanceolate blades. Few other species in Central America have white chalky sap, and no other species with white sap have narrow, non-cordate blades.

2. Philodendron cretosum is not easily confused with any other species in Central America. It resembles Philodendron tenuipes Engl., from Ecuador, which also has elongated blades with acute bases and persistent cataphyll fibers, but that species differs in having blades drying darker brown with the primary lateral veins closer and more numerous (more than 15 pairs) and smaller spathes (usually less than 7.5 cm long).

3. One collection, Gomez et al. 19121, reportedly from the slopes of Volcán Miravalles along the Guanacaste–Alajuela border at about 1500 m, would be well above the confirmed elevational range and in a Lower Montane rainforest life zone. It is doubtful if it was collected in this life zone or at that elevation. Neither Mike Grayum nor I have encountered this species above 600 m.

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Philodendron cretosum

2. Annals of the Missouri Botanical Garden 84: 427 (1997) — protologue.

3. iNaturalist: Philodendron cretosum

Additional photos from iNaturalist by ramon_d, Nate Hartley and sprinklerbird