Zamia montana Braun (1875: 376)

Calonje, Michael, Morales, Gustavo, López-Gallego, Cristina & Roldán, Francisco Javier, 2015, A taxonomic revision of Zamia montana and Zamia oligodonta, with notes on their conservation status, Phytotaxa 192 (4), pp. 279-289 : 281-284

Zamia montana Braun (1875: 376) . Figs. 1 , 2 , 3 .

Neotype (designated by Stevenson 2001: 57): — COLOMBIA. Antioquia: Municipio de Frontino , km 17 of road Nutibara–Murrí, 1750 m, 24 September 1987, Zarucchi et al. 5724 (neotype NY!, isoneotypes COL!, HUA!, MO!).

Aulacophyllum montanum (A.Braun) Regel (1876: 141) .

Literature:— Braun (1875); Galeano et al., (2005). Regel (1876), Thiselton-Dyer (1882); Schuster (1932); Lindstrom (2009); Stevenson (2001, 2004).

Illustrations:— Galeano et al. (2005), Stevenson (2001, 2004).

Etymology:— The specific epithet references the premontane to lower montane habitat of this species, which occurs at the highest elevation of any Neotropical cycad.

Description:— Stems arborescent, to 150 × 20 cm, solitary or occasionally branching, erect or decumbent. Leaves 1–10, to 307 cm long, petiole to 170 cm, sparsely armed with prickles to 2 mm long, rachis to 137 cm long, unarmed or sparsely armed with prickles in the proximal third, Rachis to 131 cm, unarmed or sparsely armed with prickles in the proximal third, carrying up to 30 opposite to suboppositely arranged leaflets. Leaflets oblanceolate, narrowly cuneate basally, acuminate apically, coriaceous, veins forming grooves on adaxial surface, only slightly protruding on abaxial surface, margins strongly revolute except at acuminate tip, entire but sometimes uneven and slightly sinous (repand) at distal end. Middle leaflets 19.5–41 × 5.9–10.5 cm, spaced 6-10 cm apart, apical leaflets 24.6–27.7 × 6.4–9.6 cm, basal leaflets 28.5–35.5 × 5.9–8.5 cm. Eophylls unknown. Pollen strobili 1–3 per stem apex, to 13.5 × 3.5 cm, beige-yellow tomentose, peduncle 2.5–3.5 cm long, strobilar axis villous, microsporophylls arranged in 16–20 orthostichies of 20–28 sporophylls each, to 13 × 6 mm, sterile apex encompassing approximately 1/3 of total length of sporopyll, microsporangia 0.8–1.0 mm, present on both abaxial and adaxial surfaces. On adaxial surface, aggregated in single group of 10–15 sporangia limited to the distal end of fertile region, on abaxial surface, aggregated in single group of 15–20 sporangia covering entire fertile region. Ovulate strobili 1 per stem apex, erect, cylindrical, beige-yellow tomentose when juvenile (mature color not seen), to 33 × 16 cm, sterile apex obtuse, to 5 cm long, peduncle obscured by cataphylls to 4 × 4 cm. Megasporophylls arranged in up to 10 orthostichies of 7–9 sporophylls each, bullae truncate with hexagonal to oblong-hexagonal distal face 3–4 × 3–4 cm, terminal facet moderately protruding, distinct, shallowly indented. Seeds unknown.

Distinguishing features:— Zamia montana is readily distinguished by its obovate leaflets with acuminate tips which are prominently-veined, the sparse prickles on its petiole, and its arborescent habit. It differs from other species with prominently-veined leaflets in that the veins are only slightly protuberant on the abaxial side of the leaflet, whereas in the other species the veins are strongly protruding.

Distribution and habitat:— Zamia montana is endemic to the department of Antioquia, where it occurs in premontane and lower montane rain forests (sensu Holdridge 1967) on the Western Cordillera at elevations between 1750 to 2080 m. Rainfall averages 2400–2500 mm per year and is bimodal, with rainfall peaks occurring in October– November and April–May, and the driest months being December–March and July–August. The mean annual temperature is 19.2 ° C, with temperature ranging from 11.9° to 25.7° C (climate data derived from GIS analysis using Worldclim 1.4 [release 3] climate layers as described by Hijmans et al. 2005).

Soils are rich in organic matter with high content of aluminum and low content of calcium, magnesium, and potassium ( Restrepo et al. 1989) and pH ranging from 4.24 to 5.86 ( Luteyn & Sylva 1999).

Reproductive phenology:— Very little is known about the reproductive phenology of this species. Immature and near-mature pollen strobili have been collected in mid-April, and an immature but near full-sized ovulate strobilus was observed in July of 2014 ( Fig. 3d ).

Ecology:— Larvae of a butterfly species of the genus Eumaeus Hübner were observed feeding on new leaves of Z. montana ( Fig. 3b ). The pollinators of this species have not yet been observed.

Conservation status:— Zamia montana is currently known from only a single very fragmented population comprised of four subpopulations in forest fragments separated by areas cleared for pasture. There are an estimated total of 100 adult plants in an extent of occurrence of approximately 3 sq. km. These populations occur in small forest fragments surrounded by pasture, totaling an area of occupancy of less than 0.2 sq. km. Other forest fragments were visible in nearby mountains where additional populations may occur, but these have yet to be surveyed.

This species is likely one of the most threatened species in the genus. Believed to be possibly extinct ( Stevenson 2004) until our re-discovery of extant populations in 2014, the situation of remnant populations is dire. Several collection sites from the late 1980’s and early 1990’s were revisited and are now completely deforested. A single population was located with a few subpopulations occurring in small forest fragments that were scheduled for clearing by local inhabitants within a year. Recently cleared forests were surveyed where Zamia montana plants had been cut down only a few days prior to our visit. Even areas surrounding rivers and creeks, normally protected to preserve water quality, were totally deforested.

In three days of searching, no regeneration was observed, likely because most plants seen had been previously chopped down in previous habitat clearing attempts. These plants had regenerated new shoots, but likely most had not grown enough to produce strobili and reproduce. Only four out of approximately 80 plants surveyed were found that were intact, and a single fertile plant with a seed strobilus was observed ( Fig. 3d ).

The main threat to the species is habitat destruction by deforestation, primarily for the creation of cattle pasture and general colonization activities, and also for the cultivation of diverse crops such as lulo ( Solanum quitoense Lamarck [1794: 16] ).

Zamia montana is not known to occur in any protected area, and the establishment of such areas is critical to the survival to the species as well as the establishment of an ex situ conservation program (also see Galeano et al. 2005). The species should remain classified as Critically Endangered based on IUCN Criteria A3ac, B1ab(i–v)+2ab(i–v). The category suggested here is the same recommended by Galeano et al. (2005), even though the criteria are slightly different. Specific locality information has been purposefully withheld from this paper to minimize the risk of illegal harvesting of this critically endangered species.

Historical notes:— Regel (1876) transferred several species of Zamia , including Z. montana , into the genus Aulacophyllum Regel (1876: 140) based on distinct adaxial grooves on the leaflets (i.e strongly nerved leaflets) and the production of simultaneous rather than sequential leaf production. However, the group included species without strongly nerved leaflets such as Aulacophyllum ortgiesii Regel (1876: 141) , a synonym of Z. chigua Seemann (1854: 201) , and the distinction between simultaneous and sequential leaf production is not clear. Leaf production in Zamia appears to be sequential, even if in some species it may be very closely spaced as to appear almost simultaneous. Bentham & Hooker (1880) placed Aulacophyllum back into synonymy under Zamia , and all subsequent authors have followed this treatment.

Stevenson (2001) designated a 1987 collection by James L. Zarucchi as the neotype for the species as the holotype collection of Z. montana was believed to have been destroyed in the bombing of the Berlin herbarium during the Second World War.

Schuster (1932) cited a specimen labeled as “ Z. kalbreyeri U. Dammer ” in the Berlin herbarium under his treatment of Z. montana , but the species name was never validly published and therefore has no taxonomic status. This specimen was also likely destroyed with the bombing of the Berlin herbarium.

Additional specimens examined:— COLOMBIA [Nueva Granada]: Eichler s.n. ( K), mounted illustration of holotype material (original material likely destroyed) collected by Gustav Wallis and cultivated by James Veitch, 26 March 1881. Antioquia: Paramillo , 26 July 1880, Kalbreyer 1928 ( K!) ; 1882, Shuttleworth s.n. ( K!) ; Municipio de Frontino , 2080 m, 16 February 1991, Callejas et al. 10656 ( HUA!) ; 1800–1950 m, 5 July 2014, Roldán et al. 4725 ( HUA!) ; 1880–1920 m, 20 November 1986, Sánchez et al. 700 ( CUVC!, MEDEL!) ; 1900 m, 23 November 1986, Sánchez et al. 816 ( MEDEL!) ; 1750 m, 14 April 1987, Sánchez et al. 1185 ( COL!, MEDEL!) ; 14 April 1987, Sánchez et al. 1186 ( MEDEL!) .

Figures

FIGURE 1. Illustration of Z. montana leaflet drawn by August Eichler in 1881 (digitally enhanced for clarity)

FIGURE 2. Zamia montana in habitat in Antioquia, Colombia. A–B. Leaves on juvenile plants. C. Base of petiole showing sparse prickles. D. Leaf of adult-sized plant. E. Adult plant with decumbent stem 1.1 meters long. F. Middle leaflet from adult plant.

FIGURE 3. Zamia montana in habitat in Antioquia, Colombia. A. Newly emerging leaf. B. Herbivory by Eumaeus sp. Larvae. C. Arborescent trunk with 30 cm ruler for scale. D. Juvenile seed strobilus approximately 33 x 16 cm. Photograph by Marco Tulio Betancur. E. Juvenile pollen strobili, longest one approximately 12 cm long. Photograph by Julio Betancur.