ContentsPhilodendron panamensePhilodendron purulhense

Philodendron pirrense Croat, sp. nov.

TYPE: Panama. Darién: Cerro Pirre, middle slopes on western approach, 800--1050 m, 7E56'N, 77E45'W, 29 June 1988, Croat 68952 (holotype, MO--3610823--24; isotypes, B, COL, F, K, NY, PMA, US). Figures 301--305.

Planta hemiepiphytica aut terrestris; internodia 1--2 cm longa, 4--5 cm diam.; cataphylla 25--30 cm diam., acute 2-costata, persistentia ut fibrae grossae pallidae, cum frustris rubrobrunneis epidermidis; petiolus 56.5--100 cm longus, 5--8 mm diam., aliquantum complanatus adaxialiter cum costa inconspicua; lamina late ovato-cordata, 35--58 cm longa, 27--46 cm lata, in sicco brunnea; costae postica nuda 1--5 cm; inflorescentia 4; pedunculus manifeste albostriatus, 8.5--12 cm longus, 6--8 mm diam.; spatha 12--16.7 cm longa; lamina spathae extus viridi, suffusa marronina, intus alba suffusa marronina; tubo spathae extus rubrimarronino, intus atrimarronino; pistilla 5--6-locularia; loculi 20-ovulati; baccae albae.

Hemiepiphytic or sometimes terrestrial; stem to 5 cm long; internodes short, semiglossy, closely ribbed, completely enclosed in cataphyll fibers, 1--2 cm long, 4--5 cm diam.; roots to ca. 30 cm long, drying reddish brown, smooth, semiglossy, ca. 2 mm diam., closely ridged; cataphylls 25--30 cm long, sharply 2-ribbed (ribs prominently raised), reddish, drying reddish brown, persisting semi-intact, ultimately as coarse pale fibers with fragments of reddish brown epidermis; petioles 56.5--100 cm long, 5--8 mm diam., subterete, somewhat flattened near base, weakly flattened toward apex, with faint medial rib adaxially, surface densely short-lineate; blades broadly ovate-cordate, acuminate to narrowly acuminate at apex, cordate at base, 35--58 cm long, 27--46 cm wide (1.2--1.5 times longer than wide), (0.6--0.9 times longer than petiole), upper surface drying reddish brown, semiglossy, lower surface much paler; anterior lobe 24.5--48.5 cm long, 27--50 cm wide (1.7--2.3 times longer than posterior lobes); posterior lobes more or less rounded, 12.5--19 cm long, 12.5--23.5 cm wide, broadly obtuse; sinus hippocrepiform, 14 cm deep; midrib flat, paler than surface above, drying reddish brown below; basal veins 7--11 per side, with 0--1 free to base, 1--2 coalesced (4)6--8(10) cm, posterior rib well developed, naked for 1--5 cm; primary lateral veins 6--10 per side, departing midrib at a 55--65E angle, more or less straight to the margins, prominently sunken above, prominently raised below; interprimary veins distinct, fine, mostly continous, drying darker than surface below; minor veins arising from both the midrib and primary lateral veins. INFLORESCENCES 4 per axil; peduncle 8.5--12 cm long, 6--8 mm diam., prominently white striate, clearly demarcated from spathe; spathe 12--16.7 cm long (1.3--1.5 times longer than peduncle), moderately constricted above the tube; spathe blade green, tinged maroon, conspicuously and densely pale lineate-striate outside, white, tinged maroon inside; spathe tube red-maroon, inconspicuously short-lineate outside, 4--6 cm long, dark maroon inside; spadix sessile; more or less ovate, 11--13.4 cm long, broadest below the middle; pistillate portion greenish white, 2.7 cm long, 1.4 cm diam. at apex, 1.3 cm wide at base; staminate portion 10.8 cm long; staminate portion 5.7--8.3 cm long; fertile staminate portion white, tapered toward apex, 1.4 cm diam. at base, 1.3 cm diam. at middle, 8 mm diam. ca. 1 cm from apex, broadest at base, about as broad as pistillate portion; sterile staminate portion broader than the pistillate portion 1.4--1.5 cm diam. pistils 2.5 mm long, 1.2--1.4 mm diam.; ovary 5--6-locular, 1.7 mm long, 1.3 mm diam., with axile placentation, walls embedded with granular, crystal-like particles; locules 1.7 mm long, 0.4 mm diam.; ovules 20 per locule, 2-seriate, contained within gelatinous matrix (no true envelope), 0.2--0.3 mm long, longer than funicle; funicle 0.1--0.2 mm long, style 0.3 mm long, 1.3 mm diam., similar to style type B; style apex flat; stigma subdiscoid to slightly hemispheroid, weakly lobed, 1.2 mm diam., 0.1--0.3 mm high, covering entire style apex; the androecium truncate, prismatic, oblong, margins irregularly 4--6-sided; thecae oblong, 0.5 mm wide, more or less parallel to one another; sterile staminate flowers blunt, irregular, 4--6-sided, 2.1--3 mm long, 1.7 mm wide. Berries white.

Flowering in Philodendron pirrense occurs during the early rainy season, judging by post-anthesis collections from June and July.

Philodendron pirrense is endemic to Panama, where it is known for certain only from the Serranía de Pirre, at 1000 to 1560 m elevation in Premontane rain forest.

Philodendron pirrense is a member of P. sect. Philodendron subsect. Philodendron ser. Fibrosa. This species is distinguished by its short internodes, sharply two-high-ribbed cataphylls persisting as pale fibers with tiny fragments of thin, reddish brown epidermis, petioles somewhat flattened adaxially with a faint medial rib, broadly ovate-cordate blades with a well-developed posterior rib naked to the sinus up to half its length, inflorescences up to four per axil, and whitish peduncles clearly demarcated from the red spathe tube.

Philodendron pirrense is similar to P. copense, with which it shares dried leaves of similar color and persistent, reddish brown cataphylls. The latter species differs in having longer blades with the anterior lobes frequently concave along their margins and petioles with a yellowish or reddish brown flaking periderm.

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Additional specimens examined.

PANAMA. Darién: Serranía de Pirre, ca. 12 km N of Alto de Nique, 1520--1560 m, Croat 37916 (MO); ca. 9 km from Alto de Nique, 1480--1520 m, Croat 37887 (MO); Río Escucho Ruido, ca. 16 km N of Alto de Nique, 1530--1550 m, Croat 37944 (MO).