A NEW SPECIES AND A NEW NAME FOR A SUBSPECIES OF CLERODENDRUM ( LAMIACEAE ) FROM AFRICA

Recently the author did collect a Clerodendrum liana in Gabon that was matching several older specimens in the herbarium identified as C. buetnerii Gürke. However, in the field it was noted that the corollas of these herbarium specimens were completely greenish white, while the corollas of the majority of the specimens identified as C. buetnerii did have a conspicuous red or reddish throat. Detailed comparison between specimens with different coloured corollas revealed additional differences in indumentum and flower size. It became clear that two species were involved of which the species with the completely whitish corolla was still in need of a scientific name, it is baptized here as C. atlanticum Jongkind. Clerodendrum buetnerii differs from the new species by its calyx that is more or less equally pilose all over the outer surface, its stamens that are 3–5 cm exserted and its corolla lobes that are also clearly longer than in C. atlanticum. The young parts of C. buetnerii are covered with conspicuous 2–3 mm long hairs, the hairs of C. atlanticum are shorter and less conspicuous. A third species that can be confused with the other two here mentioned is C. fuscum Gürke, a species with a similar large calyx and a small and straight corolla. This species differs from the other two by its leaves that are usually strongly ovate and have always a conspicuously cordate leafbase. The corolla is white with red to purple lobes, the stamens are 2–2.5 cm exserted and the young parts are short hairy. The whitish calyx of C. fuscum is usually drying lemon-yellow, in the other species the calyx changes never to yellow when drying but usually to dull-brownish. This last species is in Gabon the most commonly collected of the three. During the recent work on the Checklist of Gabon all obscure names that could possibly represent the new species were checked and rejected. In the Flora of West Tropical Africa the new subspecies described below is mentioned as C. capitatum (Willd.) Schumach. & Thonn. var. cephalanthum (Oliv.) Baker (Huber, 1963: 440). Verdcourt (1992: 105) more recently studied related plants from


INTRODUCTION
Recently the author did collect a Clerodendrum liana in Gabon that was matching several older specimens in the herbarium identified as C. buetnerii Gürke.However, in the field it was noted that the corollas of these herbarium specimens were completely greenish white, while the corollas of the majority of the specimens identified as C. buetnerii did have a conspicuous red or reddish throat.Detailed comparison between specimens with different coloured corollas revealed additional differences in indumentum and flower size.It became clear that two species were involved of which the species with the completely whitish corolla was still in need of a scientific name, it is baptized here as C. atlanticum Jongkind.Clerodendrum buetnerii differs from the new species by its calyx that is more or less equally pilose all over the outer surface, its stamens that are 3-5 cm exserted and its corolla lobes that are also clearly longer than in C. atlanticum.The young parts of C. buetnerii are covered with conspicuous 2-3 mm long hairs, the hairs of C. atlanticum are shorter and less conspicuous.A third species that can be confused with the other two here mentioned is C. fuscum Gürke, a species with a similar large calyx and a small and straight corolla.This species differs from the other two by its leaves that are usually strongly ovate and have always a conspicuously cordate leafbase.The corolla is white with red to purple lobes, the stamens are 2-2.5 cm exserted and the young parts are short hairy.The whitish calyx of C. fuscum is usually drying lemon-yellow, in the other species the calyx changes never to yellow when drying but usually to dull-brownish.This last species is in Gabon the most commonly collected of the three.During the recent work on the Checklist of Gabon all obscure names that could possibly represent the new species were checked and rejected.
In the Flora of West Tropical Africa the new subspecies described below is mentioned as C. capitatum (Willd.)Schumach.& Thonn.var.cephalanthum (Oliv.)Baker (Huber, 1963: 440).Verdcourt (1992: 105) more recently studied related plants from East Africa including the type of C. cephalanthum Oliv.and did come with a completely different opinion.He reinstated C. cephalanthum as a distinct species and even described several subspecies in it.At the same time he did exclude what was the West African C. capitatum var.cephalanthum sensu Huber from his C. cephalanthum (Verdcourt, 1992: 106) suggesting that it should be placed close to C. capitatum.
When the author studied C. capitatum, C. cephalanthum sensu Verdcourt and the West African material formerly named C. capitatum var.cephalanthum, it became clear that the last taxon had more in common with C. cephalanthum than with C. capitatum.Especially the shape of the inflorescence, that is characteristically capitate in C. capitatum but usually more elongated in C. cephalanthum, was important for the decision to describe a new subspecies in C. cephalanthum to accommodate the nameless taxon.In the Flora of Tropical East Africa the new subspecies keys out with C. cephalanthum because of its glabrous bracts and calyx.However, the combination of its characters is not found in any of the already described subspecies.
Liana.Leafy twigs pilose.Leaves opposite, ovate-elliptic, 4.5-15 by 2-8 cm, base acute to rounded, sometimes subcordate, margin entire, apex acute to acuminate, above with scattered erect hairs, beneath with erect hairs mainly on the larger nerves, punctate,  4 or 5 pairs of main lateral nerves; petiole 4-25 mm, pilose.Inflorescence axillary, umbellate-cymose, up to 10 cm long.Calyx campanulate, 1.5-2 cm long and 1 cm wide, lobes about two times as long as tube, green to purple-red, covered with dense short glandular hairs mixed with a few ordinary hairs on the outside but on the margin with much denser and longer hairs, glabrous inside.Corolla very pale greenish white, with glandular and ordinary hairs on the outside, tube 2-2.5 cm long and 1.5 mm in diameter, with reflexed hairs inside, lobes elliptic, c. 6 by 4 mm, may be reflexed, glabrous inside.Stamens glabrous, 1.5-2 cm exserted; filaments greenish white; anthers yellow to orange-brown or dark brown, c. 2 mm long.Fruit not known.
Distribution -Known from only two localities, one in Cameroon and one in Gabon.