Commelina pallida Humb. & Bonpl. ex Willd.

Figs 2, 12; Table 1

Commelina pallida Humb. & Bonpl. ex Willd. (Willdenow 1809: pl. 87); Schlechtendal (1855: 454). – Athyrocarpus pallidus (Humb. & Bonpl. ex Willd.) B.D.Jacks. (Jackson 1893: 244).

Aclisia florida Kunth (Kunth 1843: 47), pro syn. Syn. nov.

Etymology

From the Latin ʻ palleō ʼ (meaning ʻpale, losing colourʼ) + the suffix ʻ -ida ʼ (meaning ʻtending toʼ), in reference to its pale lilac to lilac flowers.

Type material

MEXICO – Querétaro • originally collected at the mountainous plateaus between Queretaro and San Juan del Rio, cultivated at the Berlin Botanic Garden; s.dat.; fl., fr.; A.J.A. Bonpland & F.W.H.A. von Humboldt s.n.; lectotype: B [B-W01051-010]!, pro parte, material on the left, designated here; isolectotype: P [P00669531]!.

Selected material examined

MEXICO – México • Villa de Guadalupe, Bilimek; 17 Aug. 1869; fl.; E. Cosson 437; P 2ex. – Morelos • wet barranca above Cuernavaca; 21 Sep. 1896; fl.; C.G. Pringle 6567; E [E01026662], pro parte, specimen on the right, P [P01741878] pro parte, specimen on the left. – Puebla • vicinity of Puebla; 15 Aug. 1906; fl.; G. Arsène s.n.; US [US00158908]. – Querétaro • cerca de El Carmen, 11 km al E de Querétaro, sobre el camino a San Juan del Río; 16 Aug. 1986; fl.; J. Rzedowski 40344; MEXU.

Description

Herbs 50–100 cm tall, scrambling, perennial, robust, terrestrial. Roots tuberous, cylindric, with apical fusiform tubers. Rhizome short. Stems dimorphic, branched in the upper third; internodes 1.8–6.2 cm long, distally shorter, green suffused with red to completely red, sparsely strigose to strigose, with a sparse line of acicular hairs opposite to the leaves, hairs hyaline, drying light brown to golden, primary branches ascending, rooting only at the base, secondary branches longer than the primary branches, scrambling, apex suberect to erect. Leaves distichously-alternate, evenly distributed along the upper part of the stem, pseudopetiolate; sheaths 1.2–2.8 cm long, red suffused with light green to completely red, strigose, hairs acicular, hyaline, with a sparse line of setose hairs opposite to the blade, hairs acicular, drying light brown to golden, margin upright, ciliate, hairs acicular, drying light brown to golden; pseudopetiole inconspicuous to up to 6.9 mm long; blades (1.3–)1.7–9.4 × 0.6–4.2 cm, elliptic to lanceolate, straight, membranous to thinly chartaceous, adaxially dark green, generally suffused with red to vinaceous near base and along the veins, margin vinaceous, abaxially light green, adaxially sparsely strigose, hairs acicular, drying light brown to golden, abaxially strigose, hairs acicular, drying light brown to golden, base slightly asymmetric to symmetric, obtuse to round, margin flat, scabrid with prickle-hairs, apex acute to acuminate; midvein conspicuous, adaxially impressed, abaxially prominently obtuse, secondary veins 2–4 pairs, adaxially conspicuous, abaxially inconspicuous, becoming conspicuous on both sides when dry. Synflorescence composed of a solitary main florescence, restricted to the apex of the stems and forming a dense second-degree synflorescence. Inflorescences leaf-opposed, peduncle 1.5–2.6 cm long, the same length or longer than ½ length of the spathe, straight, strigose to densely strigose, hairs acicular, with a line of minute hook-hairs opposed to the spathe, hairs hyaline, drying light brown to golden; spathe 2.3–3.1 × 1.8–2.7 cm, cordate, oblique to the peduncle and pointing downwards or continuous to the peduncle and pointing upwards, concolourous with the leaves, margin sometimes suffused with vinaceous to red, internally inconspicuously mucilaginous, base free, subcordate to round, externally sparsely strigose to strigose, hairs hyaline, drying light brown to golden, margin flat, apex acute, straight, veins 3–4 pairs, inconspicuous, becoming conspicuous when dry; upper cincinnus vestigial, flowerless, peduncle inconspicuous to up to 5.6 mm long, included, gently recurved at pre-anthesis and anthesis, recurved and exserted at post-anthesis and fruit, sparsely puberulous with hook-hairs towards the apex, hairs hyaline; lower cincinnus 2–4-flowered, flowers mainly bisexual, rarely staminate, peduncle 6.8– 10.3 mm long, thickened in fruit, sparsely puberulous with minute hook-hairs towards the apex. Flowers chasmogamous, zygomorphic, enantiostylous (style gently dislocated to the opposite side to the medial stamen); floral buds 3.6–7.5 × 3.2–5.8 mm, obovoid, light green or white to pale lilac, glabrous to dorsally sparsely puberulous, hairs hyaline; pedicel 4.7–7.2 mm long, deflexed in bud and at anthesis, reflexed and elongating in fruit, light green, pilose with a mixture of acicular and hook-hairs, hairs hyaline; sepals light green, opaque, persistent and accrescent in fruit, dorsal sepal 4.7–5.6 × 1.2–1.8 mm, ovate, concave, glabrous to sparsely puberulous along the midvein, when present hairs acicular, short, hyaline, apex acute, lower sepals 5.2–6.4 × 2–3.2 mm, sessile, free, ovate, concave, glabrous, apex obtuse; paired petals 0.9–1 × 0.6–0.9 cm, clawed, claw 3.6–5.3 mm long, purple to mauve-purple, limb 6.7–7.6 × 6.1–8.9 mm, very widely reniform, pale lilac to lilac, base asymmetric, truncate, apex obtuse, medial petal 6.4–7.2 × 3.9–4.8 mm, shortly-clawed, claw 0.8–1.5 mm long, pale lilac to lilac, limb 4.3–5.8 × 2.8–3.9 mm, widely sagittate, entire, concave, concolourous with the paired petals, opaque, glabrous on both sides, apex obtuse to round; staminodes 2(–3), medial staminode completely absent or filament present but lacking the antherode, filaments 2.4–3.1 mm long, straight to arcuate-decurved, pale mauve to mauve-purple, base mauve to mauve-purple, apex purple, antherodes 0.5–0.6 × 0.7–0.9 mm, V-shaped, white, minute pollen sacs between the upper and lower lobes present, apiculate between the upper lobes, upper lobes absent to almost so, smaller than the lower, lower lobes spathulate to clavate; lateral filaments 7.4–8.9 mm long, gently sigmoid, apex recurved, geniculate distal to the middle, pale mauve to mauve-purple, base mauve to mauve-purple, apex purple, anthers 1.2–1.6 × 0.3–0.6 mm, held near the antherodes and medial anther, lanceolate-sagittate to sagittate, pale yellow to yellow, connective white to cream-coloured, pollen yellow, drying ochre; medial filament 6–7.3 mm long, arcuate-recurved, apex strongly recurved, pale mauve to mauve-purple, base mauve to mauve-purple, apex purple, anther 1.7–2.2 × 0.4–0.7 mm, held near the lateral anthers, linear sagittate to narrowly sagittate, strongly curved, pale yellow to yellow, connective hastate, white to cream-coloured, anther sacs appressed to each other, pollen yellow, drying ochre; ovary 1.9–2.7 × 1–1.5 mm, 3-carpellate, 5-ovulate, ellipsoid to widely ellipsoid, green, verrucose, glabrous, style 6.6–9.3 mm long, equalling or exceeding the stamens, sigmoid, base tapering into the ovary, apex strongly recurved, pale mauve to mauve-purple, base mauve to mauve-purple, apex purple, deciduous in fruit, stigma capitate, yellow. Capsules 1–2 per spathe, 5.9–7.6 × 3.7–4.6 mm, widely ellipsoid to oblongoid, sessile, fruit wall thick, apex rostrate, not constricted between the seeds when imature, becoming constricted between the seeds when mature, tan-coloured when mature, opaque, smooth, 3-locular, 3-valved, valves splitting to base, dorsal locule 1-seeded, dehiscent, ventral locules 2-seeded, dehiscent. Seeds dimorphic, dark brown to black; dorsal locule seed 3–3.4 × 2.2–2.5 mm, free from the fruit wall, ellipsoid, dorsiventrally compressed, ventrally flattened, slightly cleft towards the embryotega, testa shallowly rugose, with some small furrows on the side opposed to the embryotega, densely farinose, farinae cream-coloured, embryotega semilateral, inconspicuous, with a prominent apicule, hilum linear, longer than ½ the length of the seed; ventral locule seeds 2.2–2.5 × 2.1–2.3 mm, free from the fruit wall, widely ellipsoid, truncate at one end, ventrally flattened, not cleft towards the embryotega, testa shallowly rugose to irregularly rugose, densely farinose, farinae cream-coloured, embryotega semilateral to lateral, inconspicuous, with a prominent apicule, hilum linear, ca ½ the length of the seed.

Distribution

Commelina pallida is restricted to Valle de México and is confirmed to occur in the States of México, Morelos, Puebla, and Querétaro (Fig. 2). Specimens previously identified as C. pallida or C. texcocana outside Mexico (e.g., Guatemala, El Salvador, Honduras, Nicaragua, and Costa Rica) are the result of taxonomic confusion and represent a myriad of other species, including several members of both the C. diffusa and C. tuberosa groups and are, thus, excluded from the morphological characterisation and geographic distribution of C. pallida.

Ecology

It grows in high-altitude, seasonally dry forests and savannah-like formations, generally between bushes.

Phenology

It was found in bloom and fruits from August to November.

Vernacular name

Hierba del pollo (Mexico).

Conservation

Commelina pallida has a wide EOO (18 824 km 2) but a much narrower AOO (ca 256 km 2). The few known records were mainly collected before 1990, with a handful of records made after 2000. However, photographic records (iNaturalist 240395505, 239622550, 186796637, 186561037, 185768278, 184637360, 136088288, 135211974, 131518107, 130988364, 129549903, 94530608, 60203726, 17634962) confirm that the species is still extant. No information on its populational trends or its current threats is available. Thus, following the IUCN (2012) criteria and the IUCN Standards and Petitions Committee (2024) recommendations, we suggest C. pallida should be considered Endangered [EN, B2b(i, ii, iv),c(ii)].

Nomenclatural remarks

The lectotype selected by Hassemer (2020) cannot be accepted since it goes against the original diagnosis and illustration. Therefore, we designate the specimen on the left side of the sheet (B-W01051-010) as the lectotype. The name C. pallida Schltdl. was never published by Schlechtendal (1855: 454) and just represents a citation of C. pallida Humb. & Bonpl. ex Willd., an error which has been perpetuated by online databases.

Remarks

Commelina pallida is morphologically very similar to C. texcocana, and the difference between them has been the source of much debate over the years (e.g., Faden & Hunt 1987; Hunt 1993, 1994, 2001; Espejo-Serna et al. 2009; Hassemer 2020). Following Faden & Hunt (1987) and Hunt (1993, 1994, 2001), most subsequent authors have considered both species as synonyms based on them being scrambling herbs, with synflorescence composed of a solitary main florescence, spathe oblique to the peduncle and pointing downwards or continuous to the peduncle and pointing upwards, all sepals glabrous to only setose along the midvein, the paired petals limb base truncate, antherodes with upper lobes reduced and the lower lobes filiform, anthers yellow, lateral anthers held near the medial anther, stigma capitate, fruits with valves splitting all the way to the base becoming tan-coloured when mature, and brown seeds. Nonetheless, C. pallida can be differentiated from C. texcocana by its stems, leaf-sheaths, leaf-blades and spathe sparsely strigose to strigose with hairs drying light brown to golden (vs stems, leaf-sheaths and blades glabrous, spathe glabrous to velutine, when present hairs hyaline to white in C. texcocana), leaf-blades with base obtuse to round (vs cuneate obtuse to round), spathe with apex acute and straight (vs acuminate and slightly falcate), dorsal sepal glabrous to sparsely puberulous along the midvein (vs setose along the midvein), dorsal sepal ovate (vs elliptic to narrowly triangular), lower sepals parallel and ovate (vs divergent and triangular to widely trullate), petals pale lilac to lilac (vs white to light blue), and antherodes scarcely V-shaped (vs X-shaped) (Table 1). Therefore, C. pallida is reestablished as a distinct species.