12. Syngonium sagittatum Bunting,
Gentes Herb. 9:372. 1965. TYPE: Mexico,
Sierra de Juarez, at Vista Hermosa, 17.9 mi from bridge at Valle
on road to Oaxaca, Moore & Bunting 8920 (BH, holotype; MEXU,
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
the apex, weakly constricted at the base, the posterior lobes narrowly
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
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.
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.
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.
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