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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 64, No. 7 
Perennial herbs or shrubs to 1.5 m tall. Young stems subterete to subquadrate, pubescent with 
flexuose to antrorse to retrorse eglandular trichomes to 0.8 mm long and distally sometimes with 
erect subglandular and/or glandular trichomes to 0.3 mm long as well, trichomes ± concentrated in 
2 lines. Leaves (sometimes absent or nearly so during anthesis) petiolate, petioles to 20 mm long, 
blades ovate to elliptic to narrowly elliptic, (10—) 22-69 mm long, (4.5-) 6.5-32 mm wide, 1.6—4.8 
times longer than wide, subacuminate to acuminate at apex, acute to rounded to subcordate at base, 
surfaces pubescent with mostly antrorse eglandular trichomes, margin flat, ciliate with antrorse tri¬ 
chomes. Inflorescence of axillary and terminal dichasiate spikes, these often branched and forming 
panicles of spikes, rachis evenly pubescent with erect to flexuose glandular and eglandular tri¬ 
chomes 0.05-0.3 mm long, branches of panicles (when present) subtended by subulate to linear, 
sterile inflorescence bracts up to 9 mm long; dichasia (opposite, subopposite or) alternate, sessile, 
1-many-flowered. Bracts subtending dichasia opposite to subopposite, subulate to lanceolate, 1-2 
mm long, 0.4-0.5 mm wide, abaxial surface pubescent like rachis. Bracteoles triangular-subulate 
to lance-subulate, 0.9-1.5 mm long, 0.4-0.6 mm wide, abaxial surface pubescent like rachis. 
Flowers sessile to subsessile (i.e, borne on pedicels to 0.5 mm long). Calyx 2.2—4.5 mm long, abax- 
ially pubescent like rachis, lobes subulate to triangular-subulate, 1.1-2.9 mm long. Corolla entire¬ 
ly white, 8-12 mm long, externally glabrous except lower-central lobe (and extending to tube) 
externally pubescent with erect to flexuose eglandular trichomes 0.2 mm long, tube 2-2.8 mm 
long, upper lip 8-9.5 mm long, 1.5-3 mm wide, apically 2-fid with lobes to 0.1 mm long, lower 
lip 6-10 mm long, lobes 5.3-8 mm long, 2.2^1 mm wide, lower-central lobe conduplicate and par¬ 
tially enclosing stamens. Stamens 5.5-8.5 mm long, filaments glabrous, thecae 1.3-1.8 mm long; 
pollen euprolate to perprolate, 3-colporate, 6-pseudocolpate, polar diameter 48-50 pm, equatorial 
diameter 24-26 pm, colpi flanked on each side by a pseudocolpus, colpi 6.7 pm wide at equator, 
colpal surface microechinate, intercolpal surface bireticulate. Style 8-10 mm long, glabrous, stig¬ 
ma lobes 0.1-0.15 mm long. Capsule 9.5-14 mm long, pubescent with erect to flexuose eglandu¬ 
lar trichomes 0.05-0.2 mm long, stipe 4-7 mm long, head 6-7 mm long. Seeds up to 4, 4-4.1 mm 
long, 4^4.2 mm wide, surfaces papillate, margin ± swollen and pectinate with subconic tubercles 
(these sometimes united with one another and appearing as an irregularly pectinate wing). 
Phenology.— Flowering: February-March, July; fruiting: February-March. 
Distribution and habitat.— Southern Mexico (Yucatan; Fig. 1); plants occur on limestone 
in thornscrub, tropical deciduous 
forest, and tropical subdeciduous 
forest at elevations from near sea 
level to 17 m. Plants were 
observed in forest understory, 
forest edges, cut-over forest, suc- 
cessional fields, and disturbed 
areas. 
Illustrations. — Figures 
2,3. 
Figure 1. Map of southern Mexico 
(and northern Central America, shaded) 
with distributions of Carlowrightia 
yucatanensis (Yucatan), Justicia zapoteca 
(Oaxaca), Poikilacanthus foliosepalus 
(Oaxaca), and P. pochutlensis (Oaxaca). 
