Philodendron tysonii Croat, sp

Philodendron tysonii Croat, sp. nov.

TYPE: Panama. Chiriquí:Gualaca--Chiriquí Grande, 7.2 mi. beyond Los Planes de Hornito, 1165--1200 m, 8E44'N, 82E14'W, Croat 67844 (holotype, MO--3614677; isotypes, AAU, B, CAS, CM, CR, DUKE, F, GH, K, M, MEXU, NY, P, PMA, RSA, US, VEN, W). Figures 29, 425--430.

Planta plerumque hemiepiphytic, interdum terrestris; internodia 2--6 cm longa, 3.5--4 cm diam.; cataphylla (10)21--33 cm longa, incostata vel leniter 1-costata, saepe rubella, persistentia semi-intacta, demum decidua; petiolus teres vel subteres, 39--90 cm longus, 8--15 mm diam.; lamina ovata, coriacea, nitida, 32--70 cm longa, 24--50 cm lata; costa postica plerumque vix aut haud nuda, raro nuda 3 cm; inflorescentia 4--5; pedunculus 3--12 cm longus, 3--8(11) mm diam.; spatha 11.5--19 cm longa, lamina spathae extus viridi, suffusa marronina aut rubella, intus alba vel pallide viridi; tubo spathae extus suffuso marronino aut rubello, intus atrimarronina suffuso in laminam; pistilla (5)6--8(9)-locularia; loculi (4)5--7-ovulati.

Usually hemiepiphytic, appressed-climber, sometimes terrestrial; internodes short, stout, semiglossy, smooth, 2--6 cm long, 3.5--4 cm diam., dark green; roots elongate, fine, branched; cataphylls (10)21--33 cm long, unribbed to weakly 1-ribbed, sometimes sharply 2-ribbed near base and unribbed near apex, frequently reddish, frequently striate, emarginate at apex, persisting semi-intact at upper nodes, eventually deciduous, emarginate at apex; petioles 39--90 cm long, 8--15 mm diam., terete to subterete, surface densely pale-striate, glossy; sheath 10.5--11 cm long; blades ovate, coriaceous to moderately coriaceous, glossy to semiglossy, conspicuously bicolorous, acuminate at apex (the acumen sometimes inrolled and twisted), cordate at base, 32--70 cm long, 24--50 cm wide (1--1.8 times longer than wide and averaging 1.4 times), (0.4--1.1 times longer than petiole), averaging about 3/4 as long as petiole, upper surface dark green, drying dark brown to blackish brown, lower surface slightly paler, drying dark yellow-brown to greenish brown; anterior lobe 25--52.5 cm long, 20--50 cm wide (2--4.8 times longer than than posterior lobes); posterior lobes broadly rounded to broadly obtuse, 8--20 cm long, 11--22 cm wide; sinus parabolic, sometimes spatulate, (3)4--12 cm deep; midrib broadly convex to almost flat, conspicuously paler than surface above, convex to bluntly acute, darker than surface below; basal veins 5--9 per side, with (0)1(2) free to base, numbers 3--4 coalesced 1.5--3 cm; posterior rib usually scarely or not at all naked, rarely naked for 3 cm; primary lateral veins 4--10 per side, departing midrib at a 60--70E angle, moderately straight to the margins, narrowly sunken above, convex and somewhat paler than surface below; interprimary veins sunken, usually concolorous above, raised, darker than surface below; minor veins moderately distinct below, arising from both the midrib and primary lateral veins.

INFLORESCENCES 4--5 per axil; peduncle 3--12 cm long, 3--8(11) mm diam., green, finely striate; spathe 11.5--19 cm long (1.5--4.5 times longer than peduncle); spathe blade green to white, lightly to heavily tinged maroon or reddish, finely striate-speckled, margins clear outside, white to pale green inside; spathe tube tinged maroon or reddish, finely striate-speckled outside, 4.5--10 cm long, dark maroon, suffused into blade inside, weakly constricted above the tube; spadix white throughout, 10.7--15.6 cm long; pistillate portion 3.4--5.2 cm long in front, 2.4--3.1 cm long in back, broadest midway and gradually tapered toward both ends, 1.2 cm diam. at apex, 1.2--1.4 cm diam. at middle; staminate portion 7.7--9.4 cm long; fertile staminate portion white, barely constricted above the sterile staminate portion, barely tapered toward apex, 1--1.2 cm diam. at base, 1--1.2 cm diam. at middle, 6--7 mm diam. ca. 1 cm from apex; sterile staminate portion, 9--10 mm diam.; pistils 1.5--2.7 mm long, 0.8-1.6 mm diam., white; ovary (5)6--8(9)-locular, with sub-basal placenetation; locules (0.8)1.1--1.3 mm long, 0.3--0.6 mm diam.; ovules (4)5--7 per locule, (0.1)0.3--0.4 mm long, 2-seriate, contained within transparent ovule sac; style similar to style type B; stigma 0.8--1.2 mm diam., 0.2--0.3 mm high. INFRUCTESCENCE with pistillate spadix 6.5 cm long, 4 cm diam.

Flowering in Philodendron tysonii occurs mostly in June and July but also in September. In reality, flowering probably occurs from January through September or perhaps October, since post-anthesis collections have been made nearly throughout the year except February. Immature fruiting collections have been made in March, September, and November.

Philodendron tysonii is known only from Panama, but is expected to be found in the Cordillera de Talamanca of Costa Rica. It ranges from 600 to 1500 m elevation in Premontane rain forest and Tropical Lower Montane rain forest life zones.

Philodendron tysonii is a member of P. sect. Calostigma subsect. Macrobelium ser. Reticulata. This species is characterized by its stout, short (usually 3--5 cm diam.) internodes, unribbed or weakly one-ribbed, frequently reddish cataphylls persisting semi-intact (often becoming fibrous) at the upper nodes, terete to subterete petioles, and ovate-cordate blades averaging 1.4 times longer than wide and about three-fourths as long as the petioles, with 6--9 basal veins and a weakly developed posterior rib which is rarely naked at the sinus.

Philodendron tysonii is perhaps most easily confused with P. antonioanum, with which it may occur. The latter species differs in having sharply 2-ribbed cataphylls, blades drying gray-green with prominulous "cross-veins," and 4 to 6 pairs of primary lateral veins, and short-pedunculate inflorescences with spathe tubes dark magenta on both surfaces and barely constricted above. In contrast, P. tysonii has usually bluntly 1-ribbed cataphylls, blades drying more or less blackened and smooth above, 6--10 primary lateral veins, more prominently pedunculate inflorescences, and prominently constricted, spathes merely tinged red on the tube outside. In addition, the two species differ in the nature of their ovules, with P. tysonii having (5)6--8(9)-locular-ovaries with (4)5--7 ovules per locule borne in an envelope with sub-basal placentation, while P. antonioanum has 5-locular-ovaries with about 30 ovules per locule, with parietal placentation and not enveloped in an envelope.

This species may also be confused with P. sagittifolium (especially broader leaved forms), which shares blades with mostly free basal veins with posterior ribs short or lacking and scarcely or not at all naked along the sinus. The latter species differs in having narrower stems (rarely more than 3 cm diam.), green, sharply 2-ribbed deciduous cataphylls (versus persistent in P. tysonii) and blades usually somewhat reddish brown and proportionately longer (averaging about 2 times longer than broad) with the posterior lobes usually narrowly rounded. In addition, the juvenile blades of P. sagittifolium are elongated, usually oblong to narrowly triangular, and usually up to 2.5 times longer than wide (versus ovate to narrowly ovate, less than 2.5 times longer than wide, and with broadly rounded posterior lobes in P. tysonii).

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Additional specimens examined.

PANAMA. Bocas del Toro: Fortuna Dam area, Gualaca--Chiriquí Grande, just N of the Continental Divide, 850--950 m, 8E46'N, 82E17'W, Hammel et al. 14700 (MO); ca. 8.5 mi. from bridge over Fortuna Lake, 600 m, 8E46'N, 82E16'W, Croat 67005 (CAS, CM, L, MO, PMA, TEX); Cerro Colorado, 9.2 mi. W of Chame, 1450--1480 m, 8E35'N, 81E50'W, Croat 69017 (DUKE, IBE, MEXU, MO, NY, PMA, QCA, RSA, WIS); 7 mi. from Chame, ca. 1500 m, 8E35'N, 81E45'W, McPherson 8810 (MO); 5.3 mi. N of center of Fortuna Dam, Continental Divide Trail, 8E44'N, 82E17'W, Croat & Zhu 76346 (MO); near Lago Fortuna, along trail to Río Hornito, 8E45'N, 82E18'W, Croat & Zhu 76374 (MO, PMA). Chiriquí: Cerro Colorado, above San Félix, 18--27 mi. N of Pan-American Highway, 1200--1500 m, Croat 33148 (MO); 24 mi. N of Río San Félix, 1430--1500 m, 48486 (MO); 34.1 km N of Río San Félix, 1390 m, 37258 (MO); 28 mi. above Río San Félix, 1200--1500 m, 33269 (MO); from Chame to ca. 9 mi. along road, 1100--1750 m, 8E35'N, 81E54'W, Hammel & Trainer 15008 (MO, NY); Fortuna Dam area, Fortuna--Chiriquí Grande, Continental Divide, 1170 m, 8E44'N, 81E17'W, Croat 66711 (B, BR, COL, CR, K, MO, NY, PMA, US); Hammel & Kress 13490 (DUKE); Continental Divide trail, 8E44'N, 82E17'W, Croat & Zhu 76330 (K, MO, NY, SCZ, US); trail to Río Hornito, 1100--1350 m, 8E45'N, 82E15'W, McPherson 11660 (MO); Croat & Zhu 76417 (AAU, CM, ENCB, GB, IBE, M, MO, NY, PMA, TEX, WIS); confluence of Río Hornito and Río Chiriquí, 1050--1100 m, ca. 8E44'N, 82E13'W, Stevens 18376 (MO); 18377 (MO); vic. IRHE facilities, 1100--1200 m, 8E45'N, 82E08'W, Croat 66589 (AAU, COL, DUKE, F, K, MBM, MEXU, MO, P, PMA, US, VDB); 1300 m, Croat 48760 (CM, MO); Quebrada Los Chorros--Quebrada Frank, N of reservoir, 1100 m, 8E45'N, 82E13'W, Churchill & Churchill 6081 (MO); 8.3 mi. beyond Los Planes de Hornito, 1260 m, 8E44'N, 82E16'W, Croat 49943 (MO); 1300 m, 8E45'N, 82E17'W, 49821 (MO); 1400 m, 48704 (AAU, MEXU, MO, U, UC, W). Coclé: El Copé region, Alto Calvario, Continental Divide, 9.4 km above El Copé, 750--900 m, Croat 44719 (MO); 710--800 m, 89E39'N, 80E36'W, 68766 (MO, PMA); 850 m, 67577 (AAU, CM, F, G, L, MEXU, MO, NY, PMA, TEX, US); 930 m, 49203 (MO); 650--850 m, Folsom 6217 (MO). Panamá: Cerro Jefe region, vic. of summit, 9E15'N, 79E30'W, Croat & Zhu 76210 (CM, MO); Witherspoon & Witherspoon 8531 (MO); ca. 1000 m, Croat 49084 (CAS, K, MO, PMA); 1000 m, 9E15'N, 79E30'W, Knapp 2240 (MO); La Eneida, 1000 m, Luteyn & Kennedy 1775 (DUKE); 0.8 mi. beyond turnoff to Altos de Pacora, 770 m, 9E15'N, 79E29'W, Croat & Zhu 76614 (CM, MO, WIS); 3--3.5 mi. NE of Altos de Pacora, 700--750 m, 9E15'N, 79E25'W, Croat 68688 (AAU, CM, F, G, MEXU, MO, PMA, TEX, US); 800--1000 m, 22671 (F, MO); 2400 ft., Antonio 4753 (MO); Croat 67059 (AAU, B, BR, C, CAS, CM, COL, CR, DUKE, EAP, ENCB, F, HNMN, HUA, IBE, JAUM, JBGP, K, L, M, MO, NY, PMA, QCA, US, USCG, WIS); 850--900 m, 9E15'N, 79E30'W, McDonagh et al. 36 (BM); ca. 1000 m, Mori et al. 3737 (MO); ca. 950 m, ca. 9E15'N, 79E30'W, McPherson 7109 (MO); Cerro Azul--Cerro Jefe, ca. 1000 m, Luteyn 3209 (DUKE); 3000 ft., Tyson et al. 4449A (MO, SCZ); Campo Tres, ca. 700 m, Croat 27047 (F, L, MO, US); El Llano--Cartí, 6.8 mi. from highway, 350 m, Croat 49120 (MO). Veraguas: Santa Fe region, Alto Piedra--Calorébora, 3200--5600 ft., Hammel 4604 (MO); Río Tercero Brazo, beyond Alto Piedra, Croat 27328 (MO); between Río Tercero Brazo and summit of hill leading down to the Atlantic lowlands, 700 m, 8E33'N, 81E08'W, Croat 66926 (B, CAS, F, K, MO, PMA, US); Parque Nacional Cerro Tute, near Alto Piedra, 0.5 mi. N of Alto Piedra, 1250--1350 m, Croat 48955 (F, MO); 800--1030 m, Croat & Zhu 76911 (CM, MO).