12. Syngonium sagittatum Bunting, Gentes Herb. 9:372. 1965. TYPE: Mexico,

Oaxaca, Sierra de Juarez, at Vista Hermosa, 17.9 mi from bridge at Valle Nacional on road to Oaxaca, Moore & Bunting 8920 (BH, holotype; MEXU, isotype).

Juvenile plants with stems ca. 1 cm diam., drying weakly verrucose with many
slender longitudinal ridges; petioles broadly sheathed ca. 2/3 of their length; blades
triangular-elliptic, 19-23 cm long, 7-9 cm wide, the anterior lobe acuminate at
the apex, weakly constricted at the base, the posterior lobes narrowly triangular,
rounded at the apex. Adult plants with stems to ca. 2 m long, short-creeping,
closely appressed to trees; internodes green, 3-5.5 cm long, longer toward the
base of the stem, 2.5-4 cm wide; petioles 37-43 cm long, sheathed 2/3 to 3/4 its
length, subterete, weakly flattened laterally above the sheath, the sheath open,
thin along its margin; blades simple, subcoriaceous, ovate and conspicuously sagittate at the base, acuminate at the apex, 0-50 cm long, 2 - 1 cm wide, the upper surface semiglossy, light green, subbullate, the lower surface slightly paler, semiglossy, the margins revolute, the posterior lobes directed somewhat upward at an angle to midrib, usually unequal, rhomboid-triangular, obtusely angular at the apex, 12-18 cm long, usually longer than wide, frequently overlapping, the sinus spatulate to rhombic or obovate (clavate to hippocrepiform when pressed flat); primary lateral veins 9-11 pairs, prominently sunken; some interprimary veins prominently sunken; collective vein weakly sunken above, prominently to weakly raised beneath; basal veins 3-7 pairs, coalescing 1.5-7 cm from the petiole, the basal rib naked 1-5 cm.
Inflorescences 2 or 3, erect; peduncles ca. 15 cm long; spathe thick and fleshy, 15-26 cm long; spathe tube ellipsoid, 8-11 cm long, 4.5-5 cm diam., greenish outside, tinged with violet purple inside, the constriction usually at a point about midway on the staminate portion of the spadix; spathe blade 14 cm long, long-acuminate and convolute at the apex (not fully flattened, even at anthesis), greenish white; pistillate portion of the spadix 2-4 cm long, 1.5-2.2 cm diam., slightly narrower at the apex, pale green, the synandrium irregularly 4-6-sided, smooth to bumpy at the apex, densely and minutely papillate, 6 mm long, 2-3 mm diam.; staminate portion of the spadix 10.513 cm long, 2-2.5 cm diam., broadest at about the middle.
Infructescences green, pendent, weakly flattened, ca. 7 cm diam. in broadest view. Figs. 19, 20, 29.

DISTRIBUTION: Syngonium sagittatum is known for certain only from the Sierra de Judrez in eastern Oaxaca at elevations of 1200-1400 m. The area appears to be tropical wet forest.

The species is apparently most closely related to S. crassifolium of Colombia and Ecuador and has nearly identical leaves. It differs from that species in having a long-acuminate spathe. Syngonium crassifolium has a spathe which is acute or merely short-acuminate at the apex. Despite their similarities, it is doubtful that these two species are the same because of their very disjunct ranges and the fact that no other closely related plants have ever been collected between Mexico and Colombia- Ecuador.

Syngonium sagittatum is also related to S. schottianum and S. hastiferum, but of these two species it is most similar to the former, with which it shares a similar leaf shape and inflorescence. It differs from S. schottianum principally in