New Species and Transfers into Justicia (Acanthaceae)

Justicia medrani and J. zopilot ensis are described as new species while Anisacanthus gonzalezii is transferred into Justicia. The triad all have floral venation similar to red, tubular-flowered species of Just icia, though they differ from most Justicia in their tricolporate pollen with distinct pseudocolpi. In pollen and anther characters they are similar to Anisacanthus and Carlowrightia, but they differ from these in corolla vascularization and anther presentation and from Carlowrightia in corolla size. As the three taxa do not appear to represent a monophyletic group, and as Stearn has placed taxa with similar pollen into what has become a holding genus, Justicia, we include these in Justicia by default until further studies can decipher relat ionships within the genus .


INTRODUCTION
Field and herbarium studies have revealed three species of shrubby, tubular-, red-flowered, Mexican Acanthaceae that overall resemble Justicia L. (tribe Justiceae, subtribe Justiciinae) in floral characters but have anther and pollen characteristics in common with genera included in the subtribe Odontonemineae tAnisacanthus Nees, Carlowrightia A. Gray). These three species, two heretofore undescribed, have proven difficult to relate to or place into established genera in the family.
The subtribes Justiciinae and Odontonemineae have been redefined by Breme-ALISO kamp (1965) on the basis of several features but they incorporate certain unique pollen differences that were emphasized by Lindau (1895). The subtribe Justiciinae is characterized by "Knotchenpollen" (Lindau 1895) that are 2 (rarely 3) porate (or slightly colporate), prolate in outline, dorsi-ventrally flattened (when biporate), with the mesocolpia reticulately sculptured and the ora flanked by I to 3 rows of discrete islands or insulae of sexinous sculpturing (Knotchen) (Fig. If). In addition members of the subtribe have only two stamens, their anthers have 2 (occasionally I) thecae that are usually unequally inserted on the filament with broadened, sometimes oblique connectives, and one or both thecae are usually apiculate or variously muticous at the base. The corollas typically have distinct rugulae (paired ridges along the inner posterior portion of the corolla tube that partially surround the style). This subtribe includes such Mexican genera as Justicia (now including Beloperone Nees, and Jacobinia Moric.), Chaetothylax Moric., and others.
The three taxa considered here clearly have "Spangenpollen" of a type typical of the Odontoneminae. They have two stamens, no staminodia, their anthers each have two thecae that are nearly equally placed on the filaments and their thecae are basally rounded as in the Odontoneminae. Their calyces have five subulate lobes; corollas are 2-lipped, relatively large, red to orange-red, with long slightly ampliate tubes, one posterior, emarginate lobe and three smaller anterior lobes. Their anthers are borne just below the upper corolla lip near the style. One of the new taxa, however, has a rugula that partially encloses the style that Bremekamp notes is characteristic of the Justiciinae; the other two taxa do not.
In keys of Lindau (1895), Standley (1926), Shreve and Wiggins (1964) and others the three taxa key to the Odontonimeae, and because of their anther theca number, orientation, and rounded bases, and corolla size, color, and lobing, they key to the genus Anisacanthus. One of the species, in fact, is presently included in that genus (Hagen 1941).
While the three taxa agree completely with North American Anisacanthus in the technical pollen (Fig. Ie) and anther characteristics, they differ markedly in pollen presentation. In Anisacanthus filaments extend directly from the lower margins of the corolla throat and contact potential visitors on the lower sides (Henrickson and Lott 1982;Fig. 2a, b). In the three taxa under consideration here filaments separate from the corolla throat, curve upward and present the anthers directly under the upper corolla lobe in a dorsal position relative to a visitor (Fig. -a-d. Pollen of the newly described species is "Spangenpollen" with two sculptured ridges paralleling aperture.-a. J. medrani pollen differs in having scrobiculate sculpturing the tectum (Hiriart 157).-b. 1. zopilotensis pollen is structurally similar to that ofJ. medrani but has a distinct reticulate sculpturing pattern (Breedlove 35988).-c--d. J. gonzalezii (Breedlove 35915).-c. Pollen of1. gonzalezii is identical to that ofJ. zopilotensis, and Anisacanthus.d. Mesocolpal area at higher magnification showing complex reticulation pattern.-e. Anisacanthus wrightii var. wrightii. Pollen of Anisacanthus is also of "Spangenpollen" structure and is basically identical in structure and sculpturing to that of J. zopilotensis and J. gonzalezii (Henrickson 18540).f. Justicia sonorae Wasshausen has "Knotchenpollen" here with two rows of "Knotchen" or insulae bordering apertures. This pollen type is characteristic of most of Justicia and Jacobinia (R. Engard s.n.) (Scale in a = 10 /Lm and holds for a-<, f; scale in d = I /Lm.) 2c, d). The corolla lobes in these three taxa also are not elongate and strap-shaped as in Anisacanthus. In pollen presentation and corolla lobing they are more like some species of Justicia that similarly have shorter, non-strap-shaped lobes. In species of Justicia with red, tubular lowers, as well as our three taxa, filaments separate very near the corolla throat and at that point the vascular traces that go to the lower, lateral petal lobes that are situated above the stamen traces make Fig. 2. Comparison of corolla vascularization between most Jus/ida and the taxa described herein (a-b) and Anisacanthus (c--d). Both corollas receive seven vascular traces, five petal, two stamen traces with stamen traces situated below the lateral anterior petal traces. In Jus/ida and the taxa treated here, the lower lateral petal traces abruptly move around the stamen traces causing a distinct "pucker" in the outer corolla and the anthers are exserted at the top of the corolla (a-b). In Anisacanthus filament and lower, lateral petal traces do not cross and anthers are borne laterally and ventraUy (c--d).
an abrupt outward and downward shift around the stamen traces before continuing to the petal lobes (Fig. 2c,d,3c,4b,5b). This is very evident externally as a distinct and abrupt ridge bordered by depressed areas and is also seen in corollas of most taxa previously recognized as Jacobinia and Beloperone.
The basic vascularization of all these corollas is the same, consisting of seven vascular traces, five petal traces, and two stamen traces located one on each side ofthe anterior (Iower)-most trace often in close association with the lateral anterior petal traces (Fig. 2). It must be noted that not all species of Jus/ida show such abrupt trace shifts with associated external "puckers" in the corolla, for it appears to be in relation to the point of separation of the filament at the corolla throat. When filaments separate well below the throat there seems to be ample room for the lateral anterior trace to gradually tum towards the lobe. This is seen in taxa with short corollas as Justicia americana (L.) Vahl but also to some degree in taxa as Jus/ida (Jacobinia) candicans (Nees) L. Benson.
As noted above, pollen of the three new taxa is tricolporate with distinct narrow ridges separated from mesocopal areas by pseudocolpi (Spangenpollen sensu Lindau 1895), a type characteristic of the subtribe Odontoneminae.
The use of pollen characteristics in the separation of Odontoneminae from lusticiinae, however, has been criticized, as intermediate grains exist in some taxa. While most taxa in the lusticiinae have pollen with 2 pores, some genera (e.g., Drejerella Nees) have 3-pored pollen, and the number of rows of Knotchen or insulae bordering the pores varies from one to three. Lindau (1895) considered the number of rows of insulae to be characteristic of certain genera (one row in Jus/ida, two rows in Beloperone, two or three rows in Jacobinia), but the pattern is not so consistent. In some taxa with only single rows of insulae bordering the pores, the insulae are poorly separated, sometimes uniting into single linear rows similar to the distinct bands of sexinous material bordering the pseudocolpi in Spangenpollen. Raj (1961) and Steam (1971) reported that pollen of Justicia hyssopifolia L. is 2-porate with an entire band of sexinous material flanking both sides of the pores. It appears that this band is formed from the fusion of adjacent insulae. Similar united insulae are noted in two species of Drejerella (Steam 1971) and in Siphonoglossa durangensis Henrickson & Hilsenbeck by Hilsenbeck (1983). But overall, intermediate pollen types are rare. Fusion ofrows ofinsulae bordering the pores or the separation of lines into such rows may account for the evolution of these distinctive pollen types. Generic limits in the tribe Justiceae have varied greatly in the past two decades with the inclusion of Jacobinia, Beloperone, Drejerella and Dianthera L. into Justicia by Leonard (1958), Gibson (1973), Steam (1971, and the inclusion of a portion of Siphonoglossa Oerst. into Justicia by Hilsenbeck (1983). On the other hand, new genera have been erected such as Mirandea (Rzedowski 1959), Mexacanthus (Daniel 1981) and Gypsacanthus (Lott, Jaramillo, and Rzedowski 1984).
In these processes we seem to have two opposing concepts. Leonard (1958) and Gibson (1973) considered the anther characters used to separate Jacobinia, Beloperone and Dianthera from Justicia to be both minor and inconsistent and thus combined the genera, all of which have Knotchenpollen with 1-3 rows of small islands of sexine bordering the ora region. Steam (1971) went one step further and combined species of Drejerella into Justicia. Steam noted that while some species of Drejerella have Spangenpollen, in other species the line of sexinous material bordering the ora is divided into 9-12 discrete insulae as in Knotchenpollen. He further noted other variations in pore number (varying from 2 to 3) in species of Justicia and other instances of intermediacy between Lindau's Spangenpollen and Knotchenpollen, and he combines taxa with Spangenpollen into Justicia, which is usually considered to only have Knotchenpollen, The result is a large, and highly variable Justicia that has become a holding place for miscellaneous Justiceae. Steam (1971) also noted that the genus could be split up into many small genera, with Justicia s.s. encompassing only 10 species allied with the type, J. adhatoda Nees, a group that has been often incorrectly recognized as the genus Adhatoda Miller.
We have considered placing these three taxa into a new genus in the Odontoneminae based on (I) 3-colporate Spangenpollen; (2) anther thecae nearly equally placed on filament, without basal spurs or apiculations; (3) anthers borne in a posterior position; and (4) lateral anterior petal traces abruptly shifting around stamen traces.
Like other species described here J. medrani exhibits the characteristics of Spangenpollen, nearly equally inserted, subparallel, nonspurred anther sacs and stamen traces closely associated with the lower, lateral corolla lobe traces that abruptly extend around the stamen trace, leaving a distinctive external ridge on the outer corolla surface.
The species is known only from limestone slopes in the Canada del Salitre area in the Barranca de Venados in west-central Hidalgo just south of'Meztitlan where it occurs in matorral alto subinerme with species such as Acacia berlandieri Benth., While known populations of this species are small, variation was observed in development ofvestiture on lower leaf surfaces where hairs may be only 0.2-0.4, or up to 1.5 mm in length. When longer, the bent trichomes are often curved at the tips. Corollas appear orange-red in color, but portions that are shaded are more yellowish.
As with other species described here anther sacs are subparallel, without expanded connectives, they lack basal spurs and are equally inserted on the filaments (Fig. 5d), pollen is of the Spangenpollen type (Fig. lc, d) and lateral corolla lobe traces abruptly extend above the adjacent upper stamen traces. Justicia gonzalezii may be related to J. zopilotensis, with which it shares similar vestiture on the outer corolla surfaces, stems, and identical pollen sculpturing. Hagen (1941) placed this taxon in Anisacanthus but it was immediately distinguished from all other North American species by its glabrous calyces with distinctly ciliate lobes and by its distinctive floral venation.
Considerable variation was noted among the specimens of Justicia gonzalezii. Breedlove 35915 has much larger, more ovate, nearly glabrous leaves with conspicuous corneous margins and nearly glabrous stems. Daniel and Baker 3767 has stems that are very strongly strigose to villous with longer, upwardly bentcurved hairs to 0.4 mm long, smaller, more ovate-lanceolate leaves, and calyces are much larger than in other collections, measuring 8-10.5 mm in length in flower to 12 mm in fruit with calyx tubes 3.5-5 mm long. Daniel and Baker 3779 is distinguished by narrowly lanceolate to linear-lanceolate leaves not exceeding 25 mm in length, 7 mm in width.