Silene tomentosa Otth
Very rare. This species is endemic to Gibraltar.
A woody-based perennial, branching from the base. Stems erect or ascending, ranging from 15 up to 70 cm tall, with an average of around 50 cm; densely tomentose, with multicellular hairs reaching up to 0.6 mm long on the lower parts. Leaves opposite, thick and stiff, almost fleshy, densely tomentose, giving the plant a greyish-green appearance; hairs multicellular, up to 0.4 mm long, but longer around the nodes; margins entire, usually undulated. The lower leaves spathulate, round-ovate, mucronate, from 10 to 20 cm long, with an average of around 14 cm, and maximum width ranging from 2.5 to 5.5 cm with an average of around 3.5 cm. Bracts oblanceolate to linear lanceolate, up to 2.5 cm long, the lower ones shorter than the peduncles, the upper ones about as long as the peduncles. Bracteoles 3 to 4 (-5) mm long, usually longer than the pedicels. Flowers from 1.8 to 2.4 cm across, in a dense or lax thyrse (a branched panicle, the individual branches of which are dichasia). Pedicels of the central flowers 2 to 5 (-9) mm long, those of the lateral ones generally shorter from 1 to 2 (-3) mm long; densely pubescent. Petals generally pale violet but ranging from almost white to a deeper violet; claw exserted, from 13 to 17 mm long, auricled; limb obovate, bifid to over half way, from 8 to 12 mm long, without coronal scales. Calyx from 1.8 to 2.4 cm long, with an average of around 2.1 cm, umbilicate at the base, cylindrical but becoming club-shaped in fruit; densely covered with non-glandular multicellular hairs; with ten violet or green veins; the whole calyx often tinged violet, especially on those flowers which have petals of a deeper colour; calyx teeth five, obtuse, 2 to 3 mm long, with wide scarious margins which are finely ciliate. Stamens ten, hairless, exserted; anthers pale yellow, 1.8 to 2 mm long. Capsule from 1 to 1.4 cm long and up to 0.7 cm wide, ovoid, yellowish, opening by 5 or 6 teeth; carpophore 8 to 10 mm long, pubescent. Styles three, about 2 cm long, violet-tinged. Seeds reniform, tubercled, brown to greyish-brown, 1.2 to 1.4 mm long and 0.8 to 1.1 mm wide; faces flat or slightly concave; back wide, slightly rounded, flat or concave.
The only recent sightings since its discovery in 1824 were in 1979 (by L. Linares) at Green's Lodge Road, and then in 1985 (by L. Linares and A. Harper) also at Green's Lodge Road. No further sightings were made since then, until 3 plants were re-discovered by L. Linares, A. Harper and J. Cortes on 7th May 1994 at Rock Gun Road.
Attempts at growing plants from seed at the Alameda Botanic Gardens have been hugely successful, as have been the attempts to do so from seed and from micro-propagation at the Royal Botanic Gardens at Kew. First attempts at re-introduction into the wild in various places around the Rock have not been very successful, with only one plant being established at the top of Mediterranean Steps. On 9th November 2006 a number of plants were planted out on the cliff face at the top of Mediterranean Steps, with the help of members of the Cliffs and Caves section of GONHS. A couple of plants from this attempt were recorded in full bloom on 26th May 2008. On 24th April 2008 one healthy plant of around 4 to 5 years old, was recorded growing in the wild on the sand slopes of the East Side. This has been the first truly wild plant recorded since 1994.
Flowers from April to May (June).
The habitat of this species has always been taken to be coastal cliffs, but all recent sightings have been in the Rock Gun area. This, and the even more recent discovery of the plant on the East Side sand slopes, puts in doubt giving coastal cliffs as the habitat of the species.