Erica × nelsonii Fagúndez

Fagúndez, Jaime, 2012, Study of some European wild hybrids of Erica L. (Ericaceae), with descriptions of a new nothospecies: Erica nelsonii Fagúndez and a new nothosubspecies: Erica veitchii nothosubsp. asturica Fagúndez, Candollea 67 (1), pp. 51-57 : 52-54

2. Erica × nelsonii Fagúndez

( E. cinerea L. × E. tetralix L. ), nothosp. nova ( Fig. 1 ).

Hybrida ex E. cinerea et E. tetralix genita, caulibus pilis simplicibus, sine pilis multiseriatis glanduliferis, foliis marginibus partim revolutis, floribus in umbellis terminalibus axillarisque dispositis, corolla apice pubescenti, antheris appendiculis longis, ovario sparse pubescenti.

Holotypus: IRELAND. Galway: West Galway (Watsonian vice H16) 1.5 miles from Roundstone junction along the link road to Clifden. Edge of eroded peat at side of lough, 31.VIII.1964, P. F. Hunt 1636 ( K, upper left fragment).

Low shrub, ramified from the base. Stems glabrous or with some simple, woolly hairs at the apex. Leaves in whorls of 3 in young twigs and 4 in mature stems, patent or slightly erect in the upper part, 2-3 mm, ovate, with half-rolled margins on the base, some slightly curved, glabrous or almost in the adaxial surface, abaxial surface with some hairs on the midrib. Axillary fascicles of leaves sometimes present. Inflorescence a terminal umbel of 4-10 flowers. Synflorescence one to several umbels, these at the apex of long lateral branches and at the end of short branches below the apex. Hairy pedicels with simple hairs, bract and bracteoles leaf-like but reduced in size, the bract half way on the pedicel and bracteoles right below the calyx. Corolla pink, broadly urceolate, 6-7 mm with some long, simple hairs below the lobes. Ovary with some sparse hairs, mostly at the apex. Stamens with filaments geniculate below the anthers, these with slightly curved appendages, with some broad teeth on margins.

Dedicated to Ernest Charles Nelson (born in Belfast, 1951), a well-known Irish botanist with much interest and research done on European heathers.

The main differences between the new nothospecies and its parents are shown on Table 1 . It can be easily distinguished from both by its sparsely hairy ovary, from E. cinerea by its corolla and leave shape and the hairs on its corolla and from E. tetralix by the synflorescence arrangement and the lack of glandular, multiseriate hairs on leaves and stems. Leaves are 3-nate as in E. cinerea or 4-nate as in E. tetralix , in some stems the number of leaves per whorl is not clear.

This material was originally labelled as E. cinerea by P. F. Hunt, but recognized as a possible hybrid by R. Ross in 1973. He stated in a note “probably a hybrid? E. cinerea × E. mackaiana or E. cinerea × E. tetralix ”. A close study of the three plants on the sheet clearly shows that this is a hybrid. E. cinerea and E. mackayana Bab. both have a glabrous ovary therefore these cannot be the parents, as the hybrid has a hairy ovary although not as dense as in E. tetralix type. Leaves have some similarities with those of E. mackayana, with no simple hairs, but it lacks the pluricellular, multiseriate glandular hairs that characterize the leaves of E. mackayana. These are also found in E. tetralix , sometimes eglandular.

The locality of the type was intensely prospected in August 2009 but no plants with these intermediate characters were found.

Several natural hybrids involve E. tetralix : E. × watsonii ( E. ciliaris × E. tetralix ), E. × stuartii (MacFarl.) Mast. ( E. mackayana × E. tetralix ) or E. × williamsii Druce ( E. vagans L. × E. tetralix ). The only one that may involve E. cinerea is the artificial hybrid raised by K. Kramer E. × arendsiana E. C. Nelson ELSON, 2008) formed with E. terminalis Salisb. , a species with no clear systematic position, but somewhat close to E. cinerea according to some features such as seed morphology ( FAGÚNDEZ & IZCO, 2009). STURM (1901: 219) mentions the existence of the E. tetralix and E. cinerea cross in England but this is most probably a mistaken record ( GRIFFITHS, 1985).

Specimens examined. – (sub. E. tetralix ). IRELAND. Co Galway: Connemara, North margin of Ballynalinch Lake , 53º27.993’N 9º49.858’W, 110 m, 2.VIII.2009, Fagúndez 3172, 3173, 3175 ( SANT) ; “The bog road” between Roundstone and Clifden, 53º26.625’N 9º55.707’W, 70 m, 2.VIII.2009, Fagúndez 3182, 3183 ( SANT) ; North face of Mnt. Errisbeg , near Nawleney Lake , 53º24.363’N 9º58.531’W, 40 m, 3.VIII.2009, Fagúndez 3188, 3189 ( SANT) ; South margin of Ballynalinch Lake , road side near the castle, 53º27.096’N 9º52.194’W, 170 m, 2.VIII.2009, Fagúndez 3191 ( SANT).

(sub. E. cinerea ). IRELAND. Co Galway: Connemara, North margin of Ballynalinch Lake , 53º27.993’N 9º49.858’W, 110 m, 2.VIII.2009, Fagúndez 3171, 3174 ( SANT) ; North face of Mnt. Errisbeg , near Nawleney Lake , 53º24.363’N 9º58.531’W, 40 m, 3.VIII.2009, Fagúndez 3185 ( SANT) ; South margin of Ballynalinch Lake , road side near the castle, 53º27.096’N 9º52.194’W, 170 m, 2.VIII.2009, Fagúndez 3190 ( SANT).

Figures

Fig. 1. – Erica ×nelsonii Fagúndez. A. Synflorescence of upper left fragment (typus); B. General view of upper right fragment. [P. F. Hunt 1636, K] [Drawn by the author]