Orobanche rumseiana A. Pujadas & P. Fraga, 2012

Pujadas-Salvà, Antonio J. & Arguimbau, Pere Fraga I, 2012, Orobanche rumseiana A. Pujadas & P. Fraga (Orobanchaceae), a new species from the Balearic Islands, Candollea 67 (1), pp. 65-74 : 66-72

Orobanche rumseiana A. Pujadas & P. Fraga , spec. nova ( Fig. 1 , 2 ).

Typus: SPAIN. Balearic Islands, Majorca: Pollença, Cala Sant Vicenç, c. Punta de Ses Coves Blanques , 31SEE0419, 103 m, parasitic on Rosmarinus officinalis , 2.V.2003, A. Pujadas s.n. (holo-: COA [49186] ; iso-: BM, G, MA) .

Planta humilis, (7-)10-26(-35) cm alta. Caulis gracilis , ad medium 2-4,5 mm latus. Inflorescentia5,5-15(-19) × 2,3- 3 cm, cylindracea, rotundata in apice, obtusa, rare subobtusa; rhachis dense pubescente-glandulosa, cum pilis 0,2- 0,6 mm longis. Bracteae 7-12 mm longae, cum pilis glandulosis 0,1-0,5 mm longis. Bracteolae 4-7,5 × 0,7-1,5 mm, linear-lanceolatae. Calyx (6,5-)8-11,5 mm longus, dentibus triangularibus longiacuminatibus; dense piloso-glandulosus, cum pilis 0,1-0,5 mm. Corolla (14-)15- 18 mm longa, lobis obovatis, obtusis; apex loborum mucronatus (mucrousque ad 0,5 mm); corollae labiorum marginibus breviglanduloso-pilosis (ciliatis), pilis usque ad 0,3 mm. Filamenta staminales pubescentes, cum pilis 0,1-0,4 mm infra dimidium, et supra pilis glandulosis (ca. 0,1 mm) subsessilibus, sparsis infra antheras. Antherae 1,1-1,3 mm longae, pilosae ad basim, sparsis pilis ≤ 0,6 mm, interdum cadentibus. Ovarium, sicut stylus, glabrum. Parasita supra Rosmarini officinalis radices.

Small plant, (7-)10-26(-35) cm high; stem 2-4.5 mm in diameter at medium height, only slightly thickened or clavate at the base with a diameter of (5-) 7-15 mm, simple, rarely branched below ground, sometimes with sterile buds at the base, denselypubescent, indumentum ofglandular hairs 0.2- 0.6 mm long, hyaline, gland yellow or ferruginous when dry, glabrous in the lower part, stem colour whitish, usually tinged purple, becoming brown tinged dark blue when dry; basal leaves 3-13 × (2-) 3-5 mm, sparse, deltoid to lanceolate, glabrous, upper leaves 5-12 × 2-4 mm, lanceolate to widely lanceolate, minutely pubescent with glandular hairs 0.1- 0.3 mm long, indumentum dense at the base, lax towards the apex; inflorescence 5.5-15(-19) × 2.3-3 cm, dense to subdense, cylindrical, rounded apex, obtuse or rarely subobtuse; rachis with a dense indumentum of hyaline glandular hairs 0.2- 0.6 mm long, hair glands yellow or ferruginous when dry, rachis colour whitish tinged purple, becoming brown tinged deep blue when dry; flowers sessile, only sometimes the lower ones with a short peduncle up to 3 mm long; bracts (6-)7-12 × 2.5-3.5 mm, shorter than calyx, ovate to ovate-lanceolate, pubescent with hyaline glandular hairs 0.1-0.5 mm long, glands yellow or ferruginous when dry, indumentum dense, laxer towards the apex, deep purple when dry; bracteoles 4-7.5 × 0.7-1.5 mm, linear-lanceolate, purple or whitish tinged purple, deep purple or somewhat purplish blue when dry, rarely brown; calyx (6.5-) 8-11.5 mm long, with 4 triangular teeth, long acuminate, equalling the tube, lacking a fifth adaxial tooth, veins somewhat marked, calyx segments connate, abaxialy up to 3.5 mm high, adaxialy up to 1.5 mm high, not overlapping, indumentum of glandular hairs dense and uniform in the upper half, laxer towards the base, hairs 0.1-0.6 mm long, calyx segments purplish blue, deeper purple blue when dry; corolla (14-)15- 18 mmlong, bilabiate, erect-patentto patent, dorsalline uniformly curved, tubulose, base slightly inflated becoming narrow above stamen insertion, 1.7-2.4 mm wide, slightly infundibiliform towards the apex, 3.5-5 mm wide at the mouth, shortly pubescent with glandular and eglandular hairs (up to 0.2 mm) at the base, with eglandular and some glandular hairs (up to 0.3 mm) in the lower half, and predominantly with glandular hairs and some eglandular hairs (0.1-0.5 mm) in the upper half (glandular hairs hyaline, with glands hyaline or ferruginous when dry in all cases), corolla glabrous inside except at the throat folds with papillate hairs up to 0.3 mm, corolla colour whitish towards the base, often slightly tinged purple, purplish blue with deep purple veins above the filaments insertion, lobes blue to bluish-purple, becoming purplish blue when dry, upper lip bilobed, slightly emarginated, lobes with rounded apex, obtuse, with a central mucro up to 0.7 mm long, lower lip with subequal lobes or central one slightly bigger than laterals, obovate, obtuse, with a central mucro up to 0.5 mm long, margins erose, shortly ciliate with glandular hairs 0.1-0.4 mm long; stamen filaments inserted sub-horizontally, the adaxial ones to 4-5 mm from corolla base, the abaxial ones to 3.5-4.5 mm, both with hairs 0.1-0.4 mm long in the lower half and with sparse subsessile glandular hairs (ca. 0.1 mm) below the anthers, filaments white; anthers 1.1-1.3 mm long (including apiculus ca. 0.2 mm), ovate, apiculate, with sparse long hairs ≤ 0.6 mm at the base, hairs sometimes deciduous, anthers white, even when dry; ovary glabrous, purplish blue or whitish tinged purple; style glabrous, pale purplish; stigma scarcely bilobed, yellowish white; parasite on roots of Rosmarinus officinalis .

Ecology and phytosociology. – On Majorca, Orobanche rumseiana grows on a karstic, slightly sloped, rocky plateau close to the coast with a moderate influence of sea spray. It can be found in Smilaco balearicae-Ampelodesmetum mauritanicae Rivas-Martínez 1992 (alliance Oleo-Ceratonion siliquae Guinochet & Drouineau 1944; order Pistacio lentisci- Rhamnetalia alaterni Rivas-Martínez 1975; class Quercetalia Ilicis Molinier 1934) (sensu RIVAS- MARTÍNEZ & al., 2001), a Mediterranean shrubby vegetation that grows in sunny, poor soils. InMinorca, the species ismorewidelydistributed ( Fig. 3 ) and although it can onlybe found near tothe coast,it has also been observed mainly in two plant communities: in Loto tetraphylli-Ericetum multiflorae O. Bolòs & Moliner 1958 (alliance Rosmarinion officinalis Molinier 1934 ; order Rosmarinetalia officinalis Molinier 1934 ; class Rosmarinetea officinalis Rivas-Martínez & al. 1991) (sensu RIVAS- MARTÍNEZ & al., 2001) in limestone soils mostly originating from Quaternaryfossil dunes; and in Ampelodesmo mauritanicae- Ericetum scopariae O. Bolòs & al. 1970 (alliance Ericenion arboreae Rivas-Martínez & al.1986; order Pistacio lentisci- Rhamnetalia alaterni Rivas-Martínez 1975; class Quercetalia Ilicis Molinier 1934) (sensu RIVAS- MARTÍNEZ & al., 2001) in siliceous sandy soils. Both plantassociations are linked to vegetation in relatively low shrub-lands and open spaces. In all cases, it parasitizes on Rosmarinus officinalis .

Distribution, bioclimatology and biogeography. – Orobanche rumseiana is only known to grow in the Eastern Balearic Islands. It should be currently regarded as a stenochorous endemism of the coastal ecosystems where it grows in a reduced and discontinuous area, on Majorca in the north, in Serra de Tramuntana, near Cala Sant Vicenç, Pollença, but it was also reported by F. Rumsey in Alcudia; and in Minorca it is always found near to the coast (normally less than 500 m from the sea) but is more widely distributed in the north and south of the island, with at least six recorded populations ( Fig. 3 ). On this island, all attempts to locate this species in apparently favourable inland habitats have failed.

It grows in Mediterranean pluviseasonal-oceanic bioclimates, in territories inthe Thermo-Mediterranean stage. From abiogeographicstandpoint,it isincluded inthe Balearic-Catalan- Provençal Province, Balearic Subprovince, Minorcan and Majorcan Sectors (sensu RIVAS- MARTÍNEZ & al., 2002), with a typically Mediterranean maritime climate characterised by mild and rather rainy winters and veryhot and dry summers. The drought period normally lasts six or more months. It grows from 2 to 105 m above sea level. The flowering period is quite long, lasting from Aprilto early June.

Etymology. – The epithet “ rumseiana ” named after Fred Rumsey (BM) who showed the authorsthe place on Majorca where the new species grows.

Conservation status and proposals. – In the last ten years, the known population of O. rumseiana on Majorca has undergone important variations in plant number. Census figures vary, with as many as 30 individuals having been recorded in the most favourable years, compared with no plants or only a few isolated individuals in other years. Even if other populations exist, e.g. in Alcudia, as indicated by Rumsey, it is highly likely that these would also display similar variations in plant number from one yearto another. Populations on Minorca seemto be more constant in terms of plant number, at least in the last five years.

It is likely that some populations on both islands have been destroyed by urban development, particularly in coastal areas.

Moreover, a large population of feral goats has been detected on Majorca in the area of Coves Blanques, exerting strong herbivorous pressure on vegetation. It seems that goats look for Orobanche due to its juicy stem and grazed plants have been observed in this area.

For thisreason, and due tothe increasing pressureof negative human activities inrecent decades, we propose that this new species be classified as Vulnerable (VU) according to IUCN (2001) criteria.

Although all the known populations are found in areas with some type of legal protection against urban development, at regional level as is the case of the Natural Areas of Special Interest (ANEI) in the Balearic Islands, or even at European level as Sites of CommunityInterest (SCI) withinthe Natura 2000 Network , none of these legal instruments provides integral protection against threatssuch as invasive species or changes in land use. For these reasons, urgent conservation measures should be implemented to protect the populations and natural habitats of O. rumseiana .

Iconography. – BECKETT (1993: tab. 61, 4, sub Orobanche rosmarina ).

Taxonomy. – Within the subgen. Trionychon , O. rumseiana presents a number of features, described in the diagnosis, that are not normally found in any other taxon in this group. Although it has certain similarities with O. rosmarina , O. mariana and O. pseudorosmarina (see Appendix 1 for the studied specimens), important morphological differences between these taxa warrant its recognition at species level ( Table 1 ). Thus, it can be discriminated from these allied taxa mainly by the obtuse corolla lobes with a mucro up to 0.7 mm long and also by the stamen filaments, which are hairy in the lower half, with hairs up to 0.4 mmlong.

Furthermore, certain characteristics distinguish it from O. rosmarina : its thinner stem, 2-4.5 mm diameter at medium height; denselyglandular pubescent rachis(hairs 0.2-0.6 mm long); bracts with longer glandular hairs (≤ 0.5 mm); lanceolate linear bracteoles, usually narrower (0.7-1.5 mm); calyx teeth more acuminate and with denser glandular indumentum; glandular ciliate corolla margins (hairs ≤ 0.4 mm).

The differences with O. mariana are as follows: wider inflorescence (2.3-3 cm) with a more rounded and obtuse apex, rarely subobtuse; uniform and densely glandular pubescent calyx in the upper half; glandular ciliate corolla margins (hairs ≤ 0.4 mm); anthers usually shorter (1.1-1.3 mm) and ciliate at the base with a few long hairs (≤ 0.6 mm), sometimes deciduous.

The differences with O. pseudorosmarina are as follows: a taller habit (≤ 26(-35) cm); rachis with longer glandular hairs (≤ 0.6 mm); longer bracts [(6) 7-12 mm]; bracteoles usually wider (0.7-1.5 mm); longer corolla (≤ 18 mm); anthers usually longer(1.1-1.3 mm); ovary and style glabrous.

In addition to the morphological differences, these group species also display a distinct geographic distribution pattern. Thus, O. rumseiana is restricted to the eastern Balearic Islands, O. rosmarina is distributed in the southwest of continental Europe, O. mariana has onlybeen reported inSierraMorena (southwest of the Iberian Peninsula), and O. pseudorosmarina is distributed throughout coastal areas of the Eastern Mediterranean region.

Paratypi. – SPAIN. Balearic Islands, Majorca: Pollença, Cala Sant Vicenç , camí cap a la Punta de Ses Coves Blanques , 39º 55’36.17’’N 3º03’01.60’’E, 72 m, sobre Rosmarinus officinalis , 24.VII.2002, A. Pujadas s.n. ( COA [49187] ); Pollença, Cala Sant Vicenç , c. Punta de Ses Coves Blanques , 39º55’ 51.56’’N 3º03’18.46’’E, 103 m, sobre Rosmarinus officinalis , 2.IV.2003, A. Pujadas s.n. ( COA [49185 ]); Mallorca , sobre Rosmarinus officinalis , VI.1979, J. Orell 1345 (Herb. Orell-Casasnovas); Flora majoricensis 612, supra Rosmarinum legita, 6.X.1946, Palau Ferrer s.n. ( MA [114767] ) . Minorca: Ciutadella , Macarella , 31SEEE80 3215, 50 m, sobre Rosmarinus officinalis , 2.V.2010, P. Fraga s.n. ( COA [49324] ); Es Mercadal , Tirant , 31TEE 948340, 40 m, sobre Rosmarinus officinalis , 14.V.2010, P. Fraga s.n. ( COA [49325] ); Es Mercadal , Cala Blanca , 31TEE 968319, 2 m, sobre Rosmarinus officinalis , 15.V.2010, P. Fraga s.n. ( COA [49326] ); Ciutadella , Es Banyuls , 31SEE 761202, 5 m, sobre Rosmarinus officinalis , 17.V. 2010, P. Fraga s.n. ( COA [49327] ); Es Mercadal , Sa Mola de Fornells , Cala Pudent , 31TEE 988338, 10 m, sobre Rosmarinus officinalis , 25.V. 2010, P. Fraga s.n. ( COA [49328 ]); Son Olivar , Trabaluger [Trebalúger], 31SEE 8823, 100 m, 22.IV.1957, P. Montserrat s.n. ( JACA [155857] ); [probably O. rumseiana ] Alayor, Son Sancho , 20.V.1898, A. Pons y Guerau s.n. ( MA [435481] ) .

Figures

Fig. 1. – Orobanche rumseiana A. Pujadas & P. Fraga. A. Appearance; B. Flower, front view; C. Flower, side view; D. Bract; E. Open calyx; F. Calyx, side view and bracteole; G. Open corolla and androecium; H. Anther; I. Gynoecium. [A. Pujadas s.n., COA]

Fig. 2. – Orobanche rumseiana A. Pujadas & P. Fraga. [Photo by the authors]

Fig. 3. – Distribution of Orobanche rumseiana A. Pujadas & P. Fraga in Balearic Islands.

Tables

Table 1. – Main differences between Orobanche rumseiana A. Pujadas & P. Fraga, O. rosmarina Beck, O. mariana A. Pujadas and O. pseudorosmarina A. Pujadas & Muñoz Garm.

	O. rumseiana	O. rosmarina	O. mariana	O. pseudorosmarina
Plant height [cm]	(7-)10-26(-35)	(4-)6-25	(7-)10-17	9-14
Main stem width	Slim	Quite thick	Slim	Slim
Main stem diameter at halfway [mm]	2- 4.5	(3-)5-7	2-5(-6)	2.5-3.3
Inflorescence height [cm]	5.5-15(-19) × 2.3-3	5-12 × (1.5-)2-2.3	5.5-12 × 1.8-2.1	3.5-5.5 × 2.2-2.7
Inflorescence apex	Rounded, obtuse, rarely subobtuse	Rounded, obtuse	Conical, acute	Rounded, obtuse
Inflorescence rachis indumentum	Pubescent with dense glandular hairs 0.2-0.6 mm long	Thinly glandular pubescent, sparse hairs 0.1-0.4 mm long	Pubescent with dense glandular hairs 0.3-0.9 mm long	Pubescent with dense glandular hairs 0.1-0.4 mm long
Bract length [mm]	(6-)7-12	6-8	7-10	4.5-5.5
Bract, glandular hairs length [mm]	≤ 0.5	≤ 0.2	≤ 0.5	≤ 0.4
Bracteole length [mm]	4-7 × 0.7-1.5	4-7 × 1-2	5.5-7 × 0.9-1.4	3.5-6 × 0.3-0.8
Bracteole shape	Linear lanceolate	Lanceolate	Linear to linear lanceolate	Linear lanceolate
Calyx teeth shape	Triangular, long acuminate	Triangular	Narrowly triangular, long acuminate	Triangular, long acuminate
Calyx indumentum	Regularly and dense glandular pubescent, hairs ≤ 0.6 mm	Sparse glandular hairs <0.3 mm, mainly on teeth, lower part glabrous or subglabrous	Sparse glandular hairs <0.4 mm, mainly on teeth, lower part glabrous or subglabrous	Regularly and dense glandular pubescent, hairs ≤ 0.4 mm to 0.6 mm, at the lower part
Corolla length [mm]	(14-)15-18	14-16	12-16	13-16
Corolla margin indumentum	Ciliate, glandular hairs ≤ 0.4 mm	Glabrous to subglabrous, glandular hairs ≤ 0.2 mm	Glabrous to subglabrous with a few short glandular hairs ≤ 0.04 mm	Ciliate, glandular hairs ≤ 0.4 mm
Lower corolla lobes	Rounded, obtuse, with a mucro up to 0.5 mm long	Rounded, obtuse	Ovate to triangular, acute	Rounded, obtuse
Stamen filament indumentum	Hairy in the lower half, hairs ≤ 0.4 mm. Subsessile glandular hairs below anthers	Hairy in the lower half, hairs ≤ 0.1 mm. Glabrous or subsessile glandular hairs below anthers	Glabrous in the lower half. Glabrous or subglabrous with a few inconspicuous sessile glandular hairs below anthers	Glabrous at the base. Sparse glandular hairs in the upper 2/3, hairs c. 0.1 mm. Inconspicuous subsessile glandular hairs below anthers
Anther length [mm]	1.1-1.3	1.2-1.4	1.2-1.5	0.9-1.1
Anther indumentum	Sparse hairs 0.6 mm, sometimes deciduous	Glabrous	Glabrous o subglabrous with 1 or 2 hairs <0.2 mm	Hairs up to 0.3-0.4 mm
Ovary	Glabrous	Glabrous	Glabrous	Glandular hairs up to 0.2 mm. Sometimes subglabrous
Style	Glabrous	Glabrous	Glabrous	Sparse glandular hairs 0.1 mm long. Sometimes subglabrous