Ficus sytsmae Mitidieri, 2025

Mitidieri-Rivera, Nicole & Damián-Parizaca, Alexander, 2025, Ficus sytsmae (Moraceae), a new species from South America and the reinstatement of Ficus schiedeana, Phytotaxa 708 (2), pp. 167-181 : 170-175

Ficus sytsmae Mitidieri , sp. nov. ( Figs.1–4 )

TYPE:— PERU. Loreto: Maynas Province, Las Amazonas, Quebrada Sucusari , Explor Napo Camp , 13 April 1991, 03°20'S 072°55'W, R. Vasquez & N. Jaramillo 15957 (holotype: P-06863731!; isotypes: B-101298984!, MO-2025042!)

Diagnosis:— F. sytsmae is morphologically similar to F. trachelosyce , sharing a characteristic infundibuliform ostiole. F. sytsmae resembles F. trachelosyce in having a globose receptacle, but it can be readily distinguished from the latter by its leaf blade apex (caudate vs. acuminate), leaf blade base (truncate-cordate vs. acute), longer laminas (10–24 cm vs. 8–15 cm), longer petioles (3.5–13 cm vs. 2–3.5 cm), longer stipules (10–17 mm vs. 6–10 mm), larger fig diameter (12–20 mm vs. 10–12 mm), and longer ostiole length (5–7 mm vs. 2–2.5 mm) ( Figs. 2 , 4 ).

Description:— Tree 15–30 m tall or hemiepiphytic. Leafy twigs 0.5–1 cm thick, glabrous; periderm persistent. Terminal stipule 1–2 cm long, conical, brown at maturity, glabrous, caducous. Leaf blade (sub)coriaceous, oblongelliptic to elliptic, 10–24 x 5–13 cm, base truncate to cordate-rounded, apex caudate; both surfaces glabrous; midrib reaching the apex of the lamina; lateral veins brochidodromous, lateral veins 7–10 pairs, the first pair of lateral veins diverging from the midrib at an 40–45° angle, acropetiolar waxy spot at the base of the midrib beneath, not evident when dried; tertiary venation reticulate; petiole 3.5–13 cm long, ca. 2 mm thick, glabrous, the epidermis persistent. Figs axillary, solitary or in pairs, green; peduncle 0.8–1.3 cm long; epibracts 2, 1 mm long, persistent, the apex rounded, glabrous, brownish in herbarium specimens; receptacle rounded or globose, smooth or wrinkled when dried, 12–20 mm in diameter when dry, glabrescent to glabrous, brownish, green at maturity; ostiole infundibuliform, straight, 5 mm long, 5–7 mm in diameter. Flowers not seen. Fruit an achene ( Fig. 1 ).

Distribution, habitat, and phenology:— Currently, Ficus sytsmae is known to be distributed on the western slopes of the Andes in northeastern Peru (Loreto), northwestern Brazil (Acre), and southeastern Ecuador (Napo), inhabiting lowland primary forests that grow on clay and poorly drained sandy soils at elevations of 140– 450 m. Populations of Ficus sytsmae have been collected in a fertile state in April, September, and December. Due to the asynchronous flowering of the genus Ficus ( Milton 1991; Milton et al. 1982; Windsor et al. 1989), it is possible that other populations may be found in bloom throughout the year.

Conservation status:— Ficus sytsmae is assessed as Critically Endangered (EN) based on criterion D, due to the extremely small number of known mature individuals (three) across three widely separated localities in Peru, Brazil, and Ecuador. The Area of Occupancy (AOO) is estimated at <10 km ² and the species is not currently known to occur in any protected areas. Although the Extent of Occurrence (EOO) is large (~ 240,000 km ²), F. sytsmae is known from only three herbarium specimens, and no subpopulations have been documented. Projected threats such as agricultural expansion, logging, and infrastructure development may further reduce habitat quality and population viability. This is a precautionary but justified assignment based on currently available data. Additional fieldwork may result in reclassification under a different category as more data become available.

Eponymy:— Dedicated to Kenneth J. Sytsma, North American botanist and professor at the University of Wisconsin-Madison, who contributed to our understanding of Urticalean Rosids and set the stage for diversification studies in the big genus Ficus .

Additional collections (paratypes):— BRAZIL. Acre, Mun. Marechal Thaumaturgo: Rio Juruá, righ bank, “ Mato Grosso ”, ca. 8°58’16.02” S, 72°42’52.2” W, 8 December 2000, D.C. Daly, C.I. Salimon, I.S. Rivero & E.C. Oliveira 10495 (NY-00677509!). ECUADOR. Napo: Estación Biológica Jatun Sacha, 450 m, 01°04’S 77°37’W, 26 September 1988, Palacios 3028 (NY-04954975!) ( Fig. 3 ).

Discussion:— The new taxon is placed within F. sect. Americanae based on the combination of characters described in the introduction. F. sytsmae is morphologically similar to three species currently placed in the F. pertusa complex ( Pelissari et al. 2019). Among them, F. trachelosyce is the most morphologically similar to F. sytsmae , sharing an infundibuliform ostiole but differing in several vegetative characters outlined in the diagnosis. F. sytsmae also resembles F. tubulosa and F. schiedeana in having a protruded ostiole; however, it differs from these taxa by having an infundibuliform ostiole (vs. tubular in F. tubulosa and narrowly prominent in F. schiedeana ). The same vegetative characters that distinguish F. sytsmae from F. trachelosyce are also observed in comparisons with the other two species ( Table 1).

The primary difference in the size and shape of the fig between the new taxon and the other three species suggests that populations of F. sytsmae might be reproductively isolated and, therefore, have a different pollinator. However, this will only be tested through genomic sequencing and field observations of pollination biology. The main author is currently awaiting raw reads from these species and additional taxa from F. sect. Americanae to reconstruct the evolutionary history of this clade. However, characterization of the pollinators in this group has proven elusive and requires further attention, particularly with regard to possible cases of hybridization in this morphologically plastic complex. Vegetatively, the leaves of F. sytsmae are larger and more variable between populations but generally tend to be oblong, compared to those of F. trachelosyce , F. tubulosa , and F. schiedeana which are smaller and usually elliptic. Given the characteristic plasticity of vegetative traits in the F. pertusa complex, we conducted a morphometric analysis of the leaves and figs of the new taxon, along with three of the most similar species. Results are summarized in Figure 4 .

Leaf shape morphometrics ( Figure 4A–D ):— Principal Component Analisis (PCA) reveals that variation in PC1 (49.4%) primarily differentiates overall leaf shape along a continuum from obovate to narrowly lanceolate ( Fig. 4B ). Meanwhile, PC2 (34.5%) accounts for variations in apex and base morphology, ranging from caudate-rounded to long acuminate-truncate ( Fig. 4B ). F. sytsmae is distinctly segregated from the other taxa, occupying the upper panel and characterized by broadly oblong leaves with a caudate apex and a cordate-rounded base. A similar but less pronounced pattern is observed in F. schiedeana and F. tubulosa , with their morphospaces predominantly distributed within the upper right and lower left panels, respectively, albeit with some marginal overlap between the two. In contrast, Ficus trachelosyce is not easily distinguishable based solely on leaf shape, displaying substantial overlap with both F. schiedeana and F. tubulosa ( Fig. 4A ). While F. sytsmae is largely well segregated, it exhibits marginal overlap with F. tubulosa , with which it shared an overall elliptic leaf shape. However, F. sytsmae can be distinguished by its caudate apex (vs. acuminate in F. tubulosa ) and cordate to rounded base (vs. acute in F. tubulosa ) ( Fig. 4C ). Notable, leaf dimensions (length and width) in F. sytsmae are significantly different from all other species, including F. tubulosa (p-value ≈ 0) ( Fig. 4D , Appendix 1).

Fig shape morphometrics ( Figure 4E–H ):— Variation in PC1 (78.1%) explains a greater proportion of morphological divergence compared to leaf shape, indicating that fig morphology exhibits stronger interspecific differentiation. Specifically, PC1 captures variation from tubular ostioles to infundibuliform ones ( Fig. 4F ). Meanwhile, PC2 (10.3%) describes variation from obovoid figs to globose forms ( Fig. 4F ). Ficus sytsmae is well separated from F. tubulosa but remains embedded within the F. trachelosyce morphospace, with partial overlap with F. schiedeana ( Fig. 4E ). Ficus trachelosyce and F. tubulosa are overall well differentiated, occupying distinct morphospaces predominantly in the upper right and left quadrants, respectively. In contrast, F. schiedeana is challenging to distinguish based solely on fig shape. While the majority of its morphospace clusters in the lower left quadrant, characterized by globose figs with tubular ostioles, it exhibits substantial variation, resulting in partial overlap with the other three species. The fig of F. sytsmae is most similar to that of F. trachelosyce , sharing an infundibuliform ostiole. However, it can be distinguished by its significantly larger fig dimensions (length and width) than the other three species, including F. trachelosyce (p-value <0.05) ( Fig. 4H , Appendix 1).

Figures

FIGURE 1. Line drawing illustration of Ficus sytsmae. A. Twig with a fig. B. Leaf blade with acuminate apex. C. Stipule. D. Dorsal view of the fig. E. Longitudinal view of the fig. F. Basal bracts of the fig. Drawing by N. Mitidieri based on the holotype: Vasquez & N. Jaramillo 15957 (P06863731).

FIGURE 2. Digitized herbarium specimens of the four species treated in this work. A. Holotype of F. trachelosyce, Hno. Elias 682 (US1443002) © copyright of the Smithsonian Institution, NMNH,Botany (US).B.Holotype of F. tubulosa, Medeiros et al.391 (SP003455) © copyright of the Smithsonian Institution, NMNH, Botany (US). C. Lectotype of F. schiedeana, Schiede & Deppe 1116 (U0004686) © copyright of the Naturalis Biodiversity Centre, formerly Utrecht University (U). D. Holotype of F. sytsmae, R. Vásquez & N. Jaramillo 15957 (P06863731) © copyright of the Muséum National d'Histoire Naturelle (P).

FIGURE 3. Geographic distribution of Ficus sytsmae, F. trachelosyce, F. tubulosa, and F. schiedeana based on records from the holotype location and additional herbarium specimens, with leaf blade and fig outlines for every species. White asterisk (*) denotes type material.

FIGURE 4. Summary of morphometric analyses. Scatterplot of first (x-axis) and second (y-axis) axes of Principal Component Analysis from elliptic Fourier descriptors of (A) leaf shape and (E) fig shape. Summary of leaf (B) and fig (F) shape variation across first and second PCA axes plotted in (A) and (E). Heat map of leaf (C) and fig (G) of each species with major morphological differences represented by warm colors. Comparative violin plots illustrating selected morphological characters, including leaf length (leaf_L) and width (leaf_W) (D), as well as fig length (fig_L) and width (fig_W) (H), among Ficus sytsmae, F. trachelosyce, F. schiedeana, and F. tubulosa. Colors in (D) and (H) correspond to the PC plots in (A) and (E).