Justicia americana

Daniel, Thomas F., 2015, Additional Notes on North American Acanthaceae: Biogeography, Distributions, Taxonomy, Lectotypifications, and Catalog of Species, Proceedings of the California Academy of Sciences 62 (17), pp. 417-432 : 422-424

Justicia americana (L.) Vahl

UNITED STATES. Louisiana. Lafourche Parish: floating mat in Lake Boeff , C . Sasser s.n. ( NLU). St. Mary Parish: island in Atchafalaya Bay , 28 Apr 1988 (flr), F . Givens 5157 ( LSU); Salt Point , S of rd. leading W to Picnic Area from LA 317 near its terminus at Burns , 29˚34ʹ14ʺN, 91˚32ʹ07ʺW, 22 May 2007 (flr), C . Reid & P . Faulkner 6113 ( LSU). St. Tammany Parish: Pearl River WMA, E side of West Pearl River just downstream from US 90 bridge, ca. 0.8 mi E of White Kitchen , 30 Sep 2003 (flr), C . Reid & D. Moreland 4651 ( LSU); Middle Pearl River N of US 90 and S of I- 10 in Pearl River Wildlife Mgt. Area , R . Thomas et al. 77143 ( NLU); beside Mill Bayou at Middle Pearl River S of US 90, SE of Slidell, Sec. 6, T10 S, R16 E, R . Thomas et al. 119696 ( NLU). Texas. Brazos Co.: TAMU farm, 8 mi W of College Station , 30 Jun 1973 (flr), J . Saichuk 65 ( LSU). Madison Co.: Senator Ranch , Carr Lake , 23 May 1998, A . Neill 1888 ( TAMU) .

All plants identified as Justicia americana from Louisiana (noted above), and some rare individuals so identified from eastern Texas ( Daniel 2011; also noted above) grow in and along water bodies and have root systems (dense, fibrous, and extensive), foliage (mostly sessile to subsessile and linear to narrowly elliptic leaves), and corollas (e.g., lateral lobes of the lower lip diverging from the central lobe at angles of 45˚ or more) like typical representatives of the species ( Fig. 2A ). They differ from typical J. americana , which occurs from northern Mexico (Coahuila) to southern Canada (Ontario, Québec), by the opposite dichasia spread out along the inflorescence rachis to a greater extent. In typical representatives of the species, the spikes are headlike during anthesis with the median internodes mostly 1–3 mm long and the rachis is usually not or only partially visible. In the plants listed above, the spikes are more elongate with the median internodes 3.5–6 mm in length and the rachis is clearly visible. In this feature, they more closely resemble J. ovata in which the median internodes are 4 mm or more in length and the rachis is visible. The specimens listed above have been studied and can be characterized by the following description: perennial herbs growing in water, stout at base with a dense and extensive fibrous root system; leaves sessile to subsessile (petioles rarely up to 9 mm long on larger leaves), linear to narrowly elliptic, 32–125 × 7–24 mm, 4.1–7.1 × longer than wide; dichasia not headlike but ± elongate with median internodes of spike 3.5–6 mm long, rachis clearly evident. Similar root systems and leaves can be seen in other southeastern species of Justicia (e.g., J. lanceolata when they grow in water, but corollas of J. americana (both typical plants and those with the more diffuse spikes) remain distinctive from both J. lanceolata ( Fig. 2B ) and J. ovata by their widely spreading lateral lobes of the lower lip.

Typical Justicia americana with the dense, headlike spikes is the common form of the species in Texas (primarily central Texas), but remains unknown from Louisiana. Justicia lanceolata is common in eastern Texas and throughout Louisiana, where it occurs in habitats similar to those of J. americana . The distributions of J. americana and J. lanceolata in Texas were mapped and discussed by Daniel (2011). The distribution of J. ovata is discussed below.

DISTRIBUTION OF JUSTICIA OVATA

Justicia ovata is known from Alabama, Florida, Georgia, North Carolina, South Carolina, and Virginia (e.g., Wasshausen 1998; Weakley 2012). It is especially well represented in the Atlantic coastal plain of the latter five states. Small (1903) had noted the distribution of this species from Virginia to Florida and Texas. The species has not been reported from Mississippi or Texas; however, two older collections at PH, purportedly from Louisiana (“N. Orleans,” without date or collector, and “Louisiana, Dr. Hale”), appear to represent the species, and might indicate a former or very rare occurrence in that state. Thomas and Allen (1982) listed only J. lanceolata from Louisiana. More recent references to J. ovata in Louisiana (e.g., MacRoberts 1989; Thomas and Allen 1996) pertain to plants of J. lanceolata (= J. ovata var. lanceolata ) or the form of J. americana noted above, whereas others are ambiguous because collections are not cited (e.g., MacRoberts 1984). No recent collections of J. ovata from Louisiana have been located, and the current western extent of the range of this species appears to be in the Gulf coastal plain of the Florida panhandle and adjacent southern Alabama.

The species can usually be distinguished from J. americana , with which it is sometimes confused, by its less dense spikes and generally shorter and broader medial and distal leaves and less widely divergent lateral lobes of the lower lip of the corolla (which diverge from the lower-central lobe at angles less than 45°). Daniel (2011) discussed plants intermediate between J. ovata and J. americana in eastern North Carolina and southeastern Virginia, and between J. ovata and J. lanceolata in northern Florida. A specimen (Grubbs 1013 at GA) from Hickman Co., Kentucky (in the Mississippi Embayment physiographic region of the westernmost corner of that state) appears to represent J. ovata based on apparently opposite dichasia above basal node of inflorescences. However, the inflorescences are incompletely formed on this specimen, and it is possibly an abnormal individual of J. lanceolata or a hybrid between that species and J. americana (which occurs in western Kentucky). The leaves are more like those of J. lanceolata (e.g., narrowly elliptic and 4.3–7.8 times longer than wide), which occurs in nearby regions of Missouri and Illinois, and in nearby counties of westernmost Kentucky).

SPONTANEOUS OCCURRENCES OF PSEUDERANTHEMUM VARIABILE

Figures

FIGURE 2. Justicia spp. (A, B) and Pseuderanthemum variabile (C, D). A. Flower of J. americana (Daniel & Lott 10530) showing limb of corolla with lateral lobes of lower lip widely spreading from lower-central lobe. B. Flower of J. lanceolata (Daniel 11762) showing limb of corolla with lateral lobes of lower lip barely spreading from lower-central lobe. There is variation in color of the corolla in both species of Justicia. C. Spontaneous plant of P. variabile at San Francisco Conservatory of Flowers (Daniel s.n.). D. Front view of limb of corolla.