Poikilacanthus pochutlensis T.F. Daniel, 2017

Daniel, Thomas F., 2017, New and Reconsidered Mexican Acanthaceae XII, Proceedings of the California Academy of Sciences 64 (7), pp. 131-154 : 147-149

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 corollas 45–60 mm long that are externally pubescent with glandular and eglandular trichomes, and fiveaperturate 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. Martínez 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), dichasia 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). Calyx 5-lobed, 5 mm long, lobes linear, 4.5 mm long, 1.1 mm wide, similar in size, abaxially pubescent like bracteoles. Corolla bright and shiny red to orange-red, 45–60 mm long, externally pubescent with erect to flexuose eglandular and glandular trichomes 0.1– 0.8 mm long, tube 22–35 mm long, 3.5– 3.8 mm in diameter near midpoint, gradually expanded from base with no clear distinction between a narrow proximal portion and a throat, upper lip 22–25 mm long, emarginate at apex with lobes to 0.2 mm long, lower lip recoiled, up to 25 mm long. Stamens 22–24 mm long, filaments red, glabrous distally, thecae parallel, unequally inserted (overlapping by 1.6– 1.8 mm), 2.5– 2.7 mm long, ± equal in size, dorsally glabrous, lacking basal appendages; pollen oblate-spheroidal, 5-aperturate, polar diameter 57 μm, equatorial diameter 58–63 μm insulae linked into 5 loops, each of which surrounds a linear row or an elliptic band of insulae. Style 45–53 mm long, stigma equally 2-lobed, lobes 0.1 mm long. Capsule and seeds not seen.

PHENOLOGY.— Flowering: April–May; fruiting: unknown.

DISTRIBUTION AND HABITAT.— Southern Mexico (central southern Oaxaca; Fig. 1 ); plants occur very sporadically in e vergreen seasonal forest (selva mediana perennifolia), and cafetales therein, at elevations from 950 to 1150 m.

CONSERVATION.— This species is known from two collections, both from Cerro Espino ( Fig. 3 ) some 200 meters apart in elevation, from which an EOO cannot be calculated. Daniel & de Avila 12204 was collected along a trail in an overgrown and presumably abandoned (at least not maintained) coffee plantation where fewer than 10 plants were seen. The precise location of the type collection from Cerro Espino is not known; an approximation of coordinates for it is indicated above. Although the species would appear to be both local and rare, there is insufficient data to make a preliminary assessment for it other than Data Deficient (DD).

ILLUSTRATIONS.— Figures 3 , 10.

PARATYPE.— MEXICO. Oaxaca: western slope of Cerro Espino, 0.5– 1.5 km E of Finca Monte Cristo (abandoned), which is 10 km (by road) E of Mex. Hwy. 175 at jct. of turn to Toltepec , 15°52.282ʹN, 096°25.042ʹW, T . Daniel & A . de Avila 12204 ( CAS) .

DISCUSSION.— Like that of Poikilacanthus foliosepalus , pollen reveals this species to be among those that pertain to Poikilacanthus as traditionally recognized (see discussion above under P. foliosepalus ). Unlike P. foliosepalus , pollen of J. pochutlensis shows the second type described for the genus ( Daniel 1991, 1998), that is, with the insulae sharing common endwalls and arranged in loops that enclose a row or band of insulae ( Fig. 4G, H ).

The paratype was only in bud when collected ( Fig. 3 ), but has an unopened corolla 60 mm long (vs. to 49 mm long on the holotype).

Figures

FIGURE 1. Map of southern Mexico (and northern Central America, shaded) with distributions of Carlowrightia yucatanensis (Yucatán), Justicia zapoteca (Oaxaca), Poikilacanthus foliosepalus (Oaxaca), and P. pochutlensis (Oaxaca).

FIGURE 3. Photographs of Acanthaceae. Carlowrightia yucatanensis (Carnevali et al. 4381), habit (top left) and flower (top middle); Poikilacanthus pochutlensis (Daniel & de Avila 12204), apex of shoot with mature flower bud (top right) and Cerro Espino, locale of only known collections (middle right); Justicia zapoteca (Daniel et al. 11898cv), apex of shoot with inflorescence and flowers (bottom left), seed (middle center), and flower (bottom right). Photos by the author, except C. yucatanensis photos by G. Carnevali F. (used with permission).

FIGURE 10. Poikilacanthus pochutlensis. A. Photograph of holotype specimen (Torres C. & C. Martínez 4907 at FCME). B. Enlargement of inflorescence with flowers.

FIGURE 4. Pollen of Acanthaceae. A, B. Carlowrightia yucatanensis (Daniel et al. 10320), apertural view (A) and interapertural view (B). C. Justicia zapoteca (Saynes V. & Elorsa 2741), apertural view. D, E. Poikilacanthus foliosepalus (Hernández O. 326), apertural view (D) and interapertural view (E). F. Louteridium dendropilosum (Fernández N. 4189). G, H. Poikilacanthus pochutlensis (Torres & Martínez 4907), subpolar view (G) and polar view (H). I. Louteridium dendropilosum (Daniel et al. 11784), with internal contents extruding via pores.