Utricularia julianae Delprete, 2014

Delprete, Piero G., 2014, Utricularia julianae (Lentibulariaceae), a new species from the savannas of the Oyapock River, French Guiana, Phytotaxa 156 (2), pp. 74-78 : 75-78

Utricularia julianae Delprete , sp. nov. ( Fig. 1 )

Type: — FRENCH GUIANA. Commune de Regina: Savane Jardin Caché (a few km air distance from the Oyapock River) , savanna surrounded by primary forest, open field dominated by Poaceae , Cyperaceae and with frequent patches of Eriocaulaceae , soil with coarse, salt-and-pepper sand (black and white grains, of granitic origin), 04°02’52”N, 51°43’47”W, 10 m, 7 June 2013, fl. and fr., P.G. Delprete 12160 (holotype, CAY!; isotypes K!, US!) .

Delicate herb, 3.5–5.5 cm tall, single-stemmed, annual, terrestrial. Stem filiform. Rhizoids few (commonly 3–5), filiform, ca. 3.5–5.5 mm long, ca. 0.1 mm thick, without papillose branchlets. Stolons absent. Leaves apparently absent (absent at the time of collection). Traps few, present on the rhizoids, ellipsoid, 0.3 × 0.2 mm, stalked, laterally attached, the mouth lateral, with 4–5 capilliform appendages evenly distributed along the edge of the mouth trap. Internal trap glands not studied. Inflorescence erect, solitary, simple; peduncle filiform, terete, glabrous, 0.2 mm thick. Scales few, along the stem, narrowly ovate, 0.3–0.5 mm long, similar to the bracts. Bracts basifixed, narrowly ovate, 0.3–0.5 mm long. Bracteoles narrowly ovate, 0.3 mm long. Raceme with 1–2(–3) flowers, with internodes 6–9 mm long; pedicels erect, filiform, terete, 0.3–0.5 mm long. Calyx lobes subequal, membranous, glabrous, with a single central vein, upper lobe ovate, 0.8–0.9 × 0.5–0.6 mm, acute or tridentate at apex, lower lobe narrowly ovate, 0.8–0.9 × 0.4 mm, retuse at apex. Corolla pure white (white to pale purplishwhite when dry), with a yellow blotch at the base of the lower lip; upper lip 2–2.2 mm long, deeply bilobed, the lobes oblong, 1–1.2 mm long, the basal sac with a distinct, glabrous, raised marginal rim; lower lip limb 2.9–3.2 mm long, broadly ovate, with a small, basal swelling, obtuse to truncate at apex, the margin shallowly undulate to obviously crenulate; palate conspicuously ciliate with moniliform hairs; spur saccate (slightly wider near the apex), subacute at apex, straight, shorter than and perpendicular to the lower lip. Filaments slightly curved, 0.3 mm long, the anther thecae ca. 2.5 mm long, ± confluent. Ovary ovoid; style short, relatively narrow; stigma lips unequal, ovate, acute at apex, narrower than the ovary. Capsule very narrowly oblong-ovoid, 1.5–1.7 mm long, 0.4–0.5 mm wide, the wall uniformly membranous, dehiscing by a single, longitudinal, ventral slit, the placenta shortly stipitate, narrowly cylindrical, barely protruding outside the dehisced capsule. Seeds ca. 0.10 mm long.

Etymology: —The specific epithet honors my wife, Juliana Costa da Silva, who has accompanied me for many years during field and herbarium work in South America. The day of the helicopter expedition, when this plant was collected, she (at that time wife-to-be) remained at home, anxiously waiting for my return, because she believes that helicopter flights are dangerous. For these reasons, this rare, minute and precious species is dedicated to her.

Distribution, Habitat and Ecology: —The only collection known of this species is from Savane Jardin Caché (a few km by air from the Oyapock River), an open field savanna dominated by Poaceae , Cyperaceae , with frequent patches of Eriocaulaceae , and surrounded by primary forest. The observed small population, consisting of no more than 50 individuals, was growing in the semi-shade of the surrounding forest. The soil of the savanna is composed of coarse, salt-and-pepper sand (black and white grains) of granitic origin. The savanna is subjected to the two main seasons present in French Guiana: the dry season (from August to November) and the rainy season (from December to July). At the time of the collection, it was towards the end of the rainy season, when the soil of the savanna was soaked in water, but not inundated. Considering the small size of the individuals and their environmental condition, this species is doubtless ephemeral, and with a life span of just a few weeks. The single flowering collection was made in June.

Suggested conservation status: —This species is up to now only known from a single population of no more than 50 individuals, indicating that it is very rare. After four years of intense collecting in the coastal savannas of French Guiana, this is the first time that it has been seen; however, there is a small probability that it might have been overlooked, due to the small size of the individuals and its ephemeral life span. Therefore, taking into account the small area of occupancy and the small population observed this species should be treated as “Critically Endangered” (CR) following IUCN D criterium ( IUCN 2001).

Taxonomic relationships: —According to the dichotomous keys and descriptions provided by Taylor (1967: 207–209, 214; 1989: 67–73, 261), the most similar species to Utricularia julianae is U. tenuissima Tutin (1934: 334) . However, it can be distinguished from the latter (as described and illustrated by Taylor 1989: 261, fig. 67, and by Fernández-Pérez 1964: 52, fig. 16) by the leaves and stolons apparently lacking (vs. stolons few or absent, leaves few, on the stolons in U. tenuissima ), traps ellipsoid, 0.3 mm long, laterally attached, with 4–5 capilliform appendages (vs. ovoid, 0.3–0.8 mm long, basally attached, with 1 dorsal and 2 ventral, slender appendages), calyx lobes 1-veined (vs. 5-veined), calyx lower lobe retuse at apex (vs. bidentate at apex), corolla upper lip limb deeply bilobed, with lobes oblong, 1–1.2 mm long (vs. broadly ovate to round), corolla lower lip limb broadly ovate, with shallowly undulate to obviously crenulate margin (vs. round, with entire or minutely crenulate margin), spur narrowly cylindrical, parallel to the lower lip (vs. saccate, perpendicular to the lower lip), and the stigmatic branches unequal, ovate, acute at apex (vs. subequal, round, obtuse at apex). A comparative summary of the characters that differentiate these two taxa is presented in Table 1 .

It is worth noting that as concerns U. tenuissima there is a certain discrepancy between the description and illustration provided by Taylor and the type specimens. In fact, Taylor (1989: 261, fig. 67) described and illustrated U. tenuissima as having the spur parallel to the lower corolla limb lip, a feature noted by Tutin when he collected the type material, whereas the type specimens (Tutin 644, BM!, K!, L!, NY!) have the spur perpendicular to the lower limb lip.

The capsules of Utricularia tenuissima and U. julianae are quite similar by being very narrowly ovoid, dehiscing by a single longitudinal slit, and by having a shortly stipitate placenta that is projected outside the dehisced capsule. On the basis of these numerous morphological similarities, and their capsule shape and dehiscence unique within the genus, the new species is provisionally placed in sect. Martinia Taylor (1986: 7) , which was described to accommodate U. tenuissima . Further phylogenetic analyses will eventually test this placement and the monophyly of this section.

Figures

FIGURE 1. A–F. Utricularia julianae. A. Habit. B. Flower, lateral view. C. Flower, posterior view. D. Calyx, posterior view. E. Dehisced capsule, with barely protruding placenta. F. Trap, lateral view. G–K. Utricularia tenuissima. G. Flower, lateral view. H. Flower, posterior view. I. Calyx, posterior view. J. Dehisced capsule, with protruding placenta. K. Trap, lateral view. A–F: drawn from Delprete 12160; G–K: redrawn from Taylor, 1989, fig. 67. Illustration by Piero G. Delprete.

Tables

TABLE 1. Comparative table of morphological characters distinguishing Utricularia tenuissima (sensu Taylor 1989) from U. julianae.

	Utricularia tenuissima	Utricularia julianae
Stolons	Few or absent	Absent
Leaves	Few on the stolons	Absent
Traps number and position	Numerous, on leaves, stolon branches and rhizoids	Few, on rhizoids
Trap morphology	Ovoid, 0.3–0.8 mm long, basally attached, with 1 dorsal and 2 ventral slender appendages	Ellipsoid, 0.3 mm long, laterally attached, with 4–5 capilliform appendages
Calyx lobes	5-veined Upper lobe broadly ovate Lower lobe bidentate at apex	1-veined Upper lobe ovate Lower lobe retuse at apex
Corolla color	Violet, mauve or white	Pure white when fresh (white to pale purplish-white when dry)
Corolla upper lip limb	Broadly ovate to round (apex shortly bilobed)	Deeply bilobed, the lobes oblong, 1–1.2 mm long
Corolla lower lip limb	Round, margin entire or minutely crenulate	Broadly ovate, margin shallowly undulate to obviously crenulate
Spur	Narrowly cylindrical, parallel to the lower lip	Saccate, perpendicular to the lower lip
Stigmatic branches	Subequal, round, obtuse at apex	Unequal, ovate, acute at apex