A SURVEY OF THE RUBUS SPECIES (ROSACEAE) DESCRIBE!) FROM THE CANARYISLANDS

MATZKE-HAJEK, G. & H.E. WEBER. (1999). A survey of the Rubus species (Rosaceae) described from the Canary Islands. Anales Jard. Bot. Madrid 57(1): 25-35. Taxonomy, nomenclatura and distribution of the bramble species (Rubus L., subgen. Rubus) described from the Canary Islands are studied. Apart from the widespread Mediterranean R. ulmifolius Schott two species occur: R. bollei Focke (Syn.: R. canariensis Focke, R. suspiciosus Menezes) and R. palmensis A. Hansen. The latter is not an endemic of La Palma as assumed by its discoverer, but is recorded for the first time also in Gran Canaria and Tenerife. Complete descriptions are provided, and illustrations of distinctive features often lacking in herbarium specimens are presented. Problems concerning the typification are discussed. Rubus x wolfredoi-wildpretii H. E. Weber nothospec. nov., the frequent hybrid between Rubus bollei and R. ulmifolius is described as new to science. Rubus bornmuelleri Focke from Gran Canaria is based on a specimen dubium and has to be deleted from the list of Cañarían species.


INTRODUCTION
Since Focke in 1887 for the first time focused attention on the "Rubi der Cañaren" only a few attempts have been made to elucídate the taxonomy of the Cañarían bramble-flora (FOCKE, 1892(FOCKE, , 1914HANSEN, 1972). However, the descriptions, original diagnoses as well as complementary notes, are insufficient for the following reasons: 1) Focke, the author of three ñames in question (Rubus bollei, R. canariensis, R. bornmuelleri), had never seen the living plants of the Cañarían brambles he described. When he published R. bollei for example, he did not even base his findings on any herbarium specimens at all. 2) Many herbarium specimens, including type material, lack characteristic components like stem cuttings, representative leaves from light exposed shoots or typical inflorescences. Collectors were often unable to supply those parts due to the strong ramification or the tall growth of the plants. Others did not know about the requirements for sufficient and instructive herbarium material of Rubus. All this created obscurity and confusión, which were passed on to modern checklists and floras (HANSEN & SUNDING, 1985;KUNKEL, 1991;HOHENESTER &WELSS, 1993).
The intention of this contribution is thus: 1) to typify the ñames Rubus bollei Focke and R. canariensis Focke; 2) to examine critically the systematic valué and status of the Rubus taxa described from or quoted for the Canary Islands (/?. bollei Focke, R. bornmuelleri Focke, R. canariensis Focke, R. palmensis A. Hansen, R. suspiciosus Menezes); 3) to complete and rectify insufficient descriptions and to provide illustrations of distinctive characters which are often lacking in herbarium specimens.
The Mediterranean Rubus ulmifolius Schott, common and widespread also in the Canary islands is not discussed here. It has already been treated in detail by MONASTE-RIO-HUELIN & WEBER (1996).

MATERIAL
The study is based on field observations and collections by the authors on the western Canary Islands in 1969 and from 1995 to 1998. Morphological investigations on herbarium specimens have also been carried out on material from B, BM, BREM, C, COI, JE, K, P, TFC and prívate herbaria. Further institutions have been checked in vain in the search for brambles collected by Bolle.

Description
Stem high-arching up to 3 m or climbing up to 8 m, 10-25 mm diameter, strongly branched, angled with fíat or slightly furrowed sides, dark purple, glabrous or glabrescent with sparse simple hairs, prickles 6-15 per 5 cm, on the angles, subequal, with very broad triangular red base, declining (straight or) slightly curved, 4-8 mm.
Leaves (fig. la-e) digitate, leaflets 5, becoming leathery, dark green, glabrous and shining above, grey or greyish-white-feltet beneath with contrasting light-brown nerves; terminal leaflet 8-12 x 5-9 cm (in moist, moderately shady sites rich in nutrient even up to 15 x 12 cm), broadly ovate or obovate to nearly round with an acuminate(-cuspidate) apex 8-22 mm and an entire or emarginate to sometimes cordate base, more or less evenly serrate with teeth-tips straight or introrse and the principie teeth sometimes prominent, slightly convex, the petiolule 35 to 55 % as long as the laminilla; petiolules of basal leaflets 4-18 mm; petioles usually as long as or longer than basal leaflets, coloured like the stem with scattered simple and stellate hairs and 8-25 broad-based, often strongly curved prickles 3-5 mm.
Inflorescence large with a wide base of spreading peduncles, with 3-5-foliate leaves below and sometimes 1-2 simple ovate leaves, the cylindrical or conical apex leafless down to about 15 to 30 cm, but with conspicuous bracts up to 3 cm long; rachis straight with sparse to numerous simple and tufted hairs, grey-feltet above and with sparse to numerous (4-12 per 5 cm) broad-based, declining and slightly curved prickles 3-6 mm; pedicels grey-feltet, with few simple patent hairs and a very variable number (0-15) of slender curved prickles c. 1-2 mm; sepáis greyish white-feltet, short-pointed, reflexed; petáis up to 16 x 10 mm, broad-ovate, white or rarely pale pink; filaments white, exceeding the green styles; anthers and carpels glabrous; receptacle hairy; flowering in (V)VI(VII). 2n = 14 (GUSTAFSSON, 1943).

Typification of Rubus bollei
In the protologue Focke did not mention particular exsiccates, and in his herbarium (JE, BREM) no specimen of R. bollei collected in or before 1887 could be found. Focke even explicitly stated that his fragmentary description was solely based on "observations" submitted by C.A. Bolle. If at all a lectotype can be selected, it must be chosen from the plants Bolle refered to. However, there is no indication that Bolle collected the plant, although Focke called him the "discoverer" of the species. All institutions which according to TL and IH deposit parts of Bolles herbarium (B, FI, K, MO, P-CO, S, W) were checked in vain.
In any case the current concept of R. bollei is hardly founded on the poor and deficient protologue but rather on complementary descriptions and illustrations published by Focke in 1892 and 1914 respectively, after he studied Rubus specimens collected by R.P. Murray on the Canary Islands. Consequently, a neotype is selected from this material, of which six specimens could be traced (JE, B). They are labelled as follows (Murray's handwriting is given here in square brackets). All the material cited above is well preserved and belongs to the same taxon. Specimens (3) and (5) are less instructive because they lack fully developed leaves. Parts of specimens (2) and (4) were used by Focke to ¡Ilústrate the taxon; their remaining parts, however, are rather untypical and both carne from Tenerife, an island not quoted in the original description. Therefore specimen (1) has been selected as neotype. It is more complete and its provenance corresponds best to the locality mentioned in the protologue. This designation keeps up the current use of the ñame Rubus bollei.

Typification of Rubus canariensis
Analogous to R. bollei the interpretation of R. canariensis among taxonomists was dominated by Fockes later publications (1892,1914) rather than by the original diagnosis. Focke's description and illustrations -the latter based also on a specimen collected by R.P. Murray (22. Bco. del Rio near S. Cruz de la Palma, Juni 1892, R. P. Murray) -seem to show specific differences of R. canariensis from R. bollei: more evenly serrated, narrower terminal leaflets with a less fine apex, and curved prickles on the inflorescence. As a matter of fact, these characters are due to the morphological variability of R. bollei and are not considered here as taxonomically relevant features. This point of view, as a result of actual observations is also in full conformity with the lectotype: Unlike in R. bollei, Focke refered to particular herbarium exsiccates in the protologue, namely Bourgeaus Planta Canariensis No 755. The whereabouts of the specimen(s) Focke might have seen, could not be traced. The locality given by Focke is more detailed ("... in vicinitate Oppidi Orotava") than on the lectotype label. Since there is no indication that the syntype is heterogenous, the specimen in Bourgeaus own collection (P) was chosen as lectotype. It is well preserved and consists of a leaf (probably cut from a branch instead of the main barren stem) and a broad, leafy inflorescence. Especially the latter shows the typical features of R. bollei, whereas the leaf lacks the stem cutting and is therefore less instructive.

Taxonomy
Since FOCKE (1914) Rubus bollei has been placed in the series Rhamnifolii (Bab.) Focke of Sectio Rubus and belongs to the few diploid European "primary species" within the genus Rubus L. (GUSTAFSSON, 1943). Unlike apomictic bramble species, R. bollei has less constant characters due to normal sexual recombination. There is, for example, a rather broad variability in leaf size andserration (cf. fig. la-e), hairyness of leaves and stems, and length of prickles. Just as other diploid bramble species R. bollei may interbreed with other species of Subgenus Rubus and give rise to hybrids. The most widespread hybrid (R. bollei x ulmifolius), according to the frequency of the other parental species (Rubus ulmifolius), is described on page 33.
In this context it is worth noting that Focke mentioned two characters in the protologue of R. bollei which are rather unusual in this species: "rachis cum pedunculis puberula aculéis rectis parvulis sparsis armata" and "pétala... rosea". These deficiencies of the description may result from the fact that Bolle was not experienced in observing Rubus and possibly confused vegetative characters unique to R. bollei with inflorescence-features more typical of the frequent R. ulmifolius Schott and hybridogenous plants.

Description
Stem high-arching, angled, furrowed, 8-20 mm diameter, with numerous sessile glands (glabrous or) with sparse to numerous, patent, long simple hairs especially on the angles, few to many yellowish-green to redbrown gland-tipped bristles 2-5 mm and slender acides and pricklets varying from 1.5 to 6 mm; prickles chiefly on the angles, grading into pricklets or bristles and difficult to count, c. 15-30 per 5 cm, slender or with a broad base, declining and curved, yellow or light brown, 2.5-4(6) mm.

Taxonomy
The "La-Palma-Blackberry" belongs to the series Grandifolii Focke, a group represented by the Madeiran Rubus grandifolius Lowe as the type-species (ICBN, Art. 22.5). Rubus palmensis is a variable taxon, but morphological deviations can be observed within single populations and are obviously the result of environmental influences.
There are plants with leaves greyish-white feltet beneath, particularly at sunny sites, and others with leaflets "supra ut infra viridia concoloria" as described in the protologue and shown on the type material. However the leaves of the holotype specimen are not representative as far as hairyness, colour and size are concerned. Fully developed leaves are extremely large (40-50 cm and even more!), have long drip-tips and a fine serration, whereas those of the type material are considerably small (less than 30 cm) and show an abnormal coarse serration. Evidently the type specimen was collected from a shady site and cut from side branches or from the apical part of the shoot, as the diameter of the adherent axis clearly indicates. Another inconstant feature is the density of (glandtipped) bristles on stem (1 and 25 per cm side), petiolules (1-15 pro cm) and the inflorescence axis (0-10 per cm).
Obviously R. palmensis can hybridize with R. bollei. Those hybrids seem to be very rare and we could trace only one specimen of really intermediate appearance ( Rubus intermediary between R. bollei and R. ulmifolius. Differs from R. bollei by the following characters: Stem a little pruinose, usually covered with adpressed numerous to dense small (pseudo-)stellate hairs, its prickles much narrower, straigth or nearly so (not extremely broad-subtriangular with recurved tip), prickles on the petioles (of the stem leaves) and on the rachis of the inflorescence much more slender and less curved. Inflorescence usually narrower, petáis always pink. Differs from R. ulmifolius as follows: Young leaves more or less rustyred, stem leaves like those of R. bollei serrate, inflorescence usually 15-25 cm beyond the top leafless. Petáis paler pink (those of R. ulmifolius usually rose-red).
This hybrid lacks particularly the extremely broad, on the stem nearly triangular prickles of R. bollei with their distinctly recurved tips and is moreover easily to be recognized in the field by its ± rusty-reddish young leaves which rernind those of R. bollei. It is named on terms of friendship after the well known botanist Prof. Dr. Wolfredo Wildpret de la Torre, University of La Laguna (Tenerife), the leading explorer of the flora and vegetation of the Canary Islands.
The hybrid was demonstrated by the author as a fairly common plant on a joint excursión together with W. The type-specimen is proved to be a holotype, since Bornmüller wrote (in Germán) on a label "received in San Mateo from a gentleman, who possessed only this single branch". The ñame was not validly published by Bornmüller (1903), who rather intended an informal communication, stating "... description and publication will not be possible until instructive specimens are procured" (transí.).
The specimen represents a young plant (c. 25 cm in all) or a shoot derived from a rooted tip. It is probably grown at a shady site. The stem is covered with patent hairs, the small 3-nate leaves have ovate terminal leaflets and are green and hairy on both sides (illustration in Focke, 1914, p. 343). The plant lacks all components required for standard material (fully differentiated leaves, inflorescence). A reliable interpretation of its identity is therefore impossible, and it must be regarded as a specimen dubium. However, 3nate, hairy, green leaves and a hairy stem may occur in young plants also of Rubus-speáes which usually have glabrous leaves and stems, and even Rubus bollei and R. ulmifolius can show these characters unless they are grown under normal light conditions.