MONSTERA TITANUM
PROTOLOGUE: Monstera titanum Croat, M.Cedeño & O.Ortiz, published in Webbia 76: 275 (2021).
Monstera titanum Croat, M.Cedeño & O.Ortiz, sp. nov. Type: Panama. Panamá, Antón, El Valle. Valle de Antón, camino a Altos del María, 1030 m, 26 Marz 2021, M.Cedeño, O. Ortíz, J.E.Jiménez & M.Mittermeier 2385 (holotype, PMA!; isotype, USJ!, MO!).
DISTRIBUTION: Panama: Panama.
DISTRIBUTION NOTE: Panama: Bocas del Toro, Chiriquí.
SPECIES DESCRIPTION:
Robust to very robust nomadic vine, appressed-climbing habit. Seedlings: bearing foliose leaves. Juvenile plants: root climbers; stems smooth, dark or light green, sometimes with white dots, cylindrical; internodes 5– 15 cm long, 0.5–1.0 cm diam.; petiole distinct, dark or light green, sometimes with white dots, smooth, 10–25 cm long, sheathed to base of the geniculum; petiole sheath slightly persistent or completely deciduous; leaf blades with collective veins visible, obovate, subcordate to truncate at base, acuminate at apex, thinly coriaceous, 10–20 × 8–13 cm, not appressed to the phorophyte, fenestrations absent or present, arranged on both sides of the midrib and in a single row of small ellipsoid perforations, 2.0–2.7 mm long. Adult plants: root climbers; stems light or dark green, white-spotted, smooth or slightly verrucose, cylindrical; internodes 1.5–3.0 cm long, 2–10 cm diam., 0.3–0.7 times as long as wide; anchor roots black; feeder roots black; petiole light green, white-spotted, smooth or verrucose at base, 50–95 cm long, sheathed to base of the geniculum or 15 cm before; petiole sheath slightly persistent; geniculum smooth, sunken adaxially, convex abaxially, 2.0–4.5 cm long; leaf blades narrowly ovate-elliptic, subcordate at base, acuminate at apex, subcoriaceous to coriaceous, drying dark brown and semiglossy adaxially, greenish yellow to brown abaxially, 47–100 × 28–35 cm, 1.6–1.7 times longer than wide, decurrent on geniculum (decurrent portion 1–2 mm wide); midrib flattened adaxially, convex abaxially, drying reddish, light brown or black on both surfaces; primary lateral veins 20–40 per side, strongly sunken adaxially and prominent abaxially, departing midrib at 75–95°, drying reddish, black or light brown; secondary veins parallel and reticulate toward the margin, undulate when dry; collective veins prominent; fenestrations absent or present in two or three rows, the first row along the midrib, with small perforations of 0.5–5.5 × 0.5–3.5 cm, the second and third rows near the margins, with larger perforations of 9.0–14.5 × 1.7–3.0 cm; margins entire.⁴
INFLORESCENCE:
Inflorescences on ascending stems, very large; peduncle smooth, 25–48 cm long; spathe acuminate, coriaceous, completely open, light green during development, creamy or white externally and white or creamy internally at anthesis, 16.5–47.0 × 10–20 cm, up to 10 cm longer than the spadix; spadix cream at anthesis, 18–24 cm long, 2.5–6.0 cm diam., 5.5–7.3 longer than wide; basal sterile flowers 4–5 mm long; fertile flowers 7–9 mm long; stamens 3–8 mm long, with laminar filaments; anthers 1.5–2.0 mm long; ovary rectangular in longitudinal section, ribbed, 5–6 × 2–3 mm; style hexagonal, 4–5 × 2.5–3.0 mm; stigmatophore slightly conical, 1.5–2.0 mm long; stigma circular; berries with a creamy stylar cap during development, ripe berries color unknown; seeds unknown.⁴
ECOLOGY:
Monstera titanum is endemic to Panama, where it is known from the type locality on Altos del Maria, Valle of Anton, and the border of Chiriquí and Bocas del Toro Provinces (Fortuna), at 1450–1480 m elevation in Premontane rain forest life zones. Flowering in January, March and November. Fruiting in March, June and November.⁴
ETYMOLOGY:
The species epithet, conveying enormous size, is from the greek ‘titanikos’ itself drawn from the Titans, the race of giant ancient Greek gods. It alludes to the huge size of the inflorescence, the largest known in the genus.²
NOTES:
1. Monstera titanum is characterized by its dark green stems with white dots, petioles 50–95 cm long, with the sheath slightly persistent, leaf blades subcordate at the base, with 20–40 primary lateral veins per side, departing the midrib at 75–95°, prominent collective veins, and compound fenestrations, with small fenestrations along the midrib or near the margins, and its inflorescence up to 95 cm in length.²
2. The species, a member of sect. Monstera, is characterized by its juvenile plants with narrowly ovate, often perforated leaves and adult plants growing as nomadic vines with an appressed-climbing habit, stems with short internodes, densely speckled, fully sheathed petioles with a sharply sulcate geniculum, large, narrowly ovate-elliptic, subcordate leaf blades with two rows of small elliptic fenestrations on both sides and drying pale greenish yellow-brown on the lower surface. The inflorescence is remarkable for its extraordinary size, with the peduncle and whitish, long acuminate spathe each up to almost half a meter long in very robust individuals. The spadix was often found eaten by beetles but with the spathe still intact. This is unusual as typically the spathes are much more ephemeral than the spadices. Monstera titanum is similar to Monstera alfaroi (Cedeño et al. 2020e), but differs in having smooth, light green and white-spotted petioles (vs. black-warty, light green and light brown petioles), cordate leaf-blades (vs. rounded at base), and smooth (vs. warty) peduncles (Cedeño-Fonseca et al. 2022). The populations of Monstera titanum from Fortuna need more widespread fieldwork in order to document the inflorescence, spathe and shape of the flowers. Only once has it been possible to collect this species in Fortuna with infructescence. This was during fieldwork in 2018. The authors never saw the inflorescence in development or anthesis, but the leaves and the stems are very similar to the population from Valle de Antón.⁴
3. Conservation status: Monstera titanum should be considered as data deficient (DD).²
STORY:
STORY TITLE: The largest inflorescence in the genus
The inflorescence of Monstera titanum can reach 95 cm, the peduncle and the whitish, long-acuminate spathe each nearly half a meter in very robust individuals, the largest known in the genus.² The epithet is drawn from the Titans, the race of giant gods of Greek myth.² Its companion in the same 2021 paper, Monstera gigas, holds the record for leaves, which exceed 3 m.²
The spadix was often found eaten by beetles while the spathe was still intact, which is unusual, since in most species the spathe is far more ephemeral than the spadix.⁴ The plant grows on rock walls and as an appressed climber, at Altos del María above the Valle de Antón and at Fortuna on the border of Chiriquí and Bocas del Toro. The Fortuna population has been collected in fruit only once, in 2018, and its inflorescence has never been seen developing or open.⁴
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Monstera titanum Croat, M.Cedeño & O.Ortiz
2. Webbia 76: 275 (2021) — protologue.
3. iNaturalist: Monstera titanum
Additional photos from iNaturalist by Oliver Ingold and ramon_d