DANIEL: NEW AND RECONSIDERED MEXICAN ACANTHACEAE XII 
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Phenology.— Flowering: July; fruiting: July. 
Distribution and habitat.— Southern Mexico (central Oaxaca; Fig. 1); plants occur in trop¬ 
ical deciduous forest at an elevation of 1673 m. 
Conservation. — The sole known collection of Poikilacanthus foliosepalus was made in the 
eastern portion of the Valley of Oaxaca. This species remains known only from the type locality, 
where an unknown number of individuals occurs, and from which it was collected in 2009. No 
information is known as to the current status of this species or any possible threats. Therefore, 
according to IUCN (2017) guidelines, the species has to be assessed as Data Deficient (DD). 
Illustration. — Figure 9. 
Discussion. — Poikilacanthus foliosepalus has one of the two pollen types characteristic of 
Mexican and Central American species treated in Poikilacanthus Lindau (Daniel 1991, 1998), that 
is, with four or more apertures and the entire surface covered with discrete “insulae” consisting of 
gemmate regions enclosed by thick, smooth marginal walls (Fig. 4D, E). Pollen of Hernandez O. 
326, examined with both scanning and light microscopy, appears to have four apertures, but it is 
possible that some of the grains might have five. 
Pollen appears to offer the only distinction between Poikilacanthus and Justicia (e.g., Daniel 
1991, 1998). Recent molecular phylogenetic studies of Justicieae reveal that Poikilacanthus is 
polyphyletic, with species placed in several lineages among the large, diverse, and monophyletic 
clade of New World justicioids (Kiel et al. 2017). Until such time as a comprehensive revision of 
all justicioids based on both molecular and morphological data has been completed, it seems rea¬ 
sonable to postpone generic/nomenclatural realignments and to maintain Poikilacanthus. 
This species is distinctive among Mexican and Central American Poikilacanthus (Daniel 
1991, 2010) by its wide and somewhat leafy calyx lobes (vs. up to 1.5 mm wide in the other 
species). A species of Ruellia (Ruellieae) with similar subfoliose calyx lobes was recently 
described by Daniel (2008) from Guerrero. Poikilacanthus foliosepalus also appears to be unique 
among its Mexican and Central American congeners by the four-aperturate (vs. five- or more-aper- 
turate) pollen (Daniel 1998, 2010). 
Poikilacanthus pochutlensis T.F. Daniel, sp. nov. 
Poikilacanthus pochutlensis differs from congeners by its dense and terminal dichasiate spikes 
with opposite dichasia, linear calyx lobes 4.5 mm long and 1.1 mm wide, red to orange-red corol¬ 
las 45-60 mm long that are externally pubescent with glandular and eglandular trichomes, and five- 
aperturate pollen with linked insulae forming loops around rows of insulae. 
Type.— MEXICO. Oaxaca: Distr. Pochutla, Cerro Espino, Finca Montecristo, 
[ca. 15°52’11.39”N, 096°24’50.89”W], 1150 m, selva mediana perennifolia, 5-IV-1984 (fl), 
R. Torres & C. Martinez 4907 (holotype: FCME!). 
Perennial herbs or shrubs to 1 m tall. Young stems densely and ± evenly pubescent with 
retrorse eglandular trichomes to 0.4 mm long. Leaves petiolate, petioles to 25 mm long, blades 
ovate to elliptic, 42-100 mm long, 20-50 mm wide, length:width = 1.6-2.5, acute to acuminate at 
apex, (rounded to) cuneate to attenuate at base. Inflorescence of dense, often very short, terminal 
spikes to 16 mm long (excluding corollas), rachis densely and evenly pubescent with flexuose to 
retrorse to retrorsely appressed eglandular trichomes to 0.4 mm long (appearing ± floccose), dicha¬ 
sia opposite, 1 per axil, 1-flowered, sessile. Proximal bracts subfoliose, ovate, 11-28 mm long, 
5.5-8 mm wide, distal bracts oblong to broadly elliptic to obovate-elliptic, 7-11 mm long, 2.5-4 
mm wide, all bracts abaxially and marginally pubescent with antrorse to antrorsely-appressed 
eglandular trichomes 0.05-0.6 mm long. Bracteoles lance-ovate, 5.5-6 mm long, 0.9-1.5 mm 
wide, abaxial surface pubescent like bracts (or with trichomes becoming flexuose to retrorse). 
