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Main
Characteristics
Phylogenetic Analysis
Generic Description & Key to Species
S. hahnianus
Additional Specimens Examined
S. hoffmannii
Additional Specimens Examined
S. parviflorus
Additional Specimens Examined
Acknowledgments & Literature Cited
Figure Legend:
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
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Spathacanthus parviflorus Leonard, Proc. Biol. Soc. Wash. 50: 15. 1937.---TYPE: GUATEMALA.
Quezaltenango: Volcán Zunil, 7 Aug 1934, A. Skutch 961 (holotype: US!; isotypes: A!, BM!, L!, NY!, US!).
Branched shrubs or small trees to 7.6 m tall. Young stems subquadrate to somewhat compressed, internodes
glabrous or sparsely bifariously pubescent with antrorsely appressed eglandular trichomes 0.2--0.5 mm long, nodes
usually with a few stiff, straight to flexuose eglandular trichomes to 0.5 mm long. Leaves petiolate, petioles
to 45 mm long, blades ovate-elliptic to elliptic to obovate-elliptic, 18--205 mm long, 11--100 mm wide, 1.6--3.7
times longer than wide, (rounded to) acute to acuminate (often abruptly so) to subfalcate at apex, acute at base,
surfaces and margin glabrous (or with antrorse eglandular trichomes along major veins on abaxial surface).
Inflorescence usually of terminal racemes or thyrses to 12 cm long (excluding flowers), sometimes with racemes
or pedunculate dichasia in axils of distalmost pair of leaves as well (see discussion), rachis glabrous or bifariously
pubescent with antrorse to antrorse-appressed eglandular trichomes 0.2--0.3 mm long; dichasia 1-flowered (except
for those sometimes borne in axils of distalmost leaves which are often 3-flowered), sessile or pedunculate, peduncles
to 18 mm long, glabrous. Bracts triangular to subulate, 1.3--6 mm long, 0.8--1.4 mm wide, abaxial surface
glabrous or with antrorsely appressed eglandular trichomes (especially along midvein), proximalmost pair often
subfoliose and larger. Bracteoles and secondary bracteoles triangular to subulate to linear, 1--2.7 (--4)
mm long, 0.6--1 mm wide, abaxial surface glabrous or pubescent like bracts. Flowers pedicellate, pedicels
to 13 mm long, 1--2.5 mm in diameter in fruit, glabrous. Calyx greenish yellow to pale yellow prior to fruiting
(becoming green as fruit matures), 15--26 (--31) mm long, 6.5--11 mm in diameter (measured flat), abaxially glabrous,
beaked in bud with a beak 1--3.5 mm long, divided into 2 lance-ovate to ovate segments with unequal incisions of
7--17 (--20) mm on 1 side and 1--6 (--16) mm on the other, longer incision 0.45--0.89 times as long as calyx, 1
segment apically (entire to) 2-lobed, lobes triangular, 0.3--0.7 mm long, other segment apically (entire to) 3-lobed,
lobes triangular, 0.6--0.8 mm long. Corolla white, 23--29 mm long, narrow proximal portion of tube 7--14
mm long, 1.8--4 mm in diameter, densely pubescent internally with coarse eglandular trichomes, throat 12--18 mm
long, 5--7.5 mm in diameter at widest expanse, limb 5--8 mm in diameter, upper lip 2--3 mm long, lobes rounded,
1.5--3 mm long, 1.5--2 mm wide, lower lip 2.5--3.5 mm long, lobes rounded, 1--3 mm long, 1.5--2.5 mm wide.
Stamens with longer pair 11--15 mm long and shorter pair 8--12 mm long, thecae 3--4.5 mm long; pollen prolate spheroidal
to euprolate, 3--4-colporate, polar diameter 39--51 µm, equatorial diameter 28--43 µm, P:E = 1.14--1.40,
exine foveolate to fossulate to verrucate to rugulate. Style 10--17 mm long, stigma lobes 0.4--0.9 mm long.
Capsule 40--54 mm long, stipe 20--25 mm long, head 17--25 mm long, retinacula 5--7 mm long. Seeds subcircular
to ± squarish in outline, 7--10 mm long, 6.5--8 mm wide, 2.7 mm thick, surface with low verrucose ridges
or bumps or becoming smooth.
Illustration. Fieldiana, Bot. 24(10): 446, fig. 101, 1974.
Phenology. Flowering: throughout the year; fruiting: September--February.
Distribution (Fig. 4). Mexico (Chiapas) and Guatemala (Chimaltenango, Quezaltenango, San Marcos, Sololá,
and Suchitepéquez); plants occur along streams, on slopes, and on ridges in rain forests and cloud forests;
730--2030 m.
Local names. "Huesco de pollo" (Heath & Long MA84); "aritas de montaña"
(Steyermark 33507); "violeta de montaña" (White 5419).
This species is restricted to the Pacific escarpment in southern Mexico (Sierra Madre de Chiapas) and Guatemala
(along the volcanic axis). The above description has been augmented with data from many more collections
than were studied by Daniel (1995a).
The inflorescence of Spathacanthus parviflorus is commonly a terminal raceme (i.e., dichasia sessile and
flowers pedicellate). Sometimes racemes arise from the axils of the distalmost pair of leaves resulting in
what appears as a basally branched panicle of racemes. Other times, pedunculate dichasia arise from one or
both axils of the distalmost pair of leaves. In some specimens (e.g., Steyermark 46632) the inflorescence
is a thyrse (i.e., dichasia pedunculate more or less throughout the inflorescence).
In addition to the distinctions noted above in the key to species, Spathacanthus parviflorus further differs
from other species of the genus by its smaller pollen which has a tendency to be 4-aperturate (see discussion above).
[Additional Specimens Examined]
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