Billolivia D.J.Middleton, 2014

Billolivia D.J.Middleton View in CoL , gen. nov.

Most similar to Cyrtandra in the indehiscent fruits and two fertile stamens but differing most obviously in the alternate leaf arrangement rather than the opposite or pseudoalternate leaf arrangement of Cyrtandra .

Type species:— Billolivia longipetiolata D.J.Middleton & Luu

Caulescent perennial herbs with short decumbent stems which root at the nodes; pubescence mostly of multicellular uniseriate brown hairs. Leaves generally crowded towards stem apex, alternately arranged, petiolate, blade simple, subcoriaceous to coriaceous, margin dentate or crenate, sometimes minutely so, secondary venation pinnate, eucamptodromous. Inflorescences axillary, sessile or shortly petiolate, cymose, flowers crowded. Calyx of 5 free lobes or connate at base into a tube and then 5-lobed at apex, sometimes in 2 lips, persistent in fruit. Corolla zygomorphic, composed of a narrow tube and spreading limb, limb 2-lipped, upper lip 2-lobed, lower lip 3-lobed. Fertile stamens 2; inserted on inside of corolla tube around or slightly above the middle of tube; filaments narrower at base, usually curved, becoming more strongly curved or coiling post maturity; anthers dorsifixed, thecae parallel, confluent at very apex, dehiscing longitudinally, coherent by apices, touching face to face; 2 lateral and one medial staminodes. Disc an annular or crenate ring, sometimes 5-lobed. Ovary cylindrical, bicarpellate, unilocular with two parietal placentae, ovules numerous; stigma 2-lobed. Fruit a fusiform or ellipsoidal indehiscent berry, not fleshy. Seeds tiny, numerous, ellipsoidal.

Etymology: — The genus is named after the late Brian Laurence Burtt (1913–2008), known as Bill Burtt, and after Olive Hilliard (1925–). The two of them made significant contributions to Gesneriaceae taxonomy and left several notes and observations on specimens of the new species described below. These notes included speculations on whether the plants belonged to Cyrtandra or should be described in a new genus. The notes did not include suggestions of new names for the genus or species. The inspiration for naming the genus by combining their given names comes from Bill Burtt himself who, in the same manner, coined the genus name Kaisupeea B.L.Burtt after Kai and Supee Larsen ( Burtt 2000).

Distribution: — The five known species are endemic to the southern Annamite range in southern Vietnam but some of these species, or additional undiscovered species, may also occur in neighbouring Cambodia. The Annamite range is known to be an area of high biodiversity and home to many endemic species of plants ( Averyanov et al. 2003).

Notes: — All species are reported to occur in evergreen forest, often in gullies or along streams on wet soils. The similar species Billolivia minutiflora and B. vietnamensis are lowland species found at 200–600 m altitude. Likewise the similar species Billolivia longipetiolata and B. violacea are highland species found at 1400–1950 m altitude. The closer relatedness of the two species pairs is reflected in sister positions in the phylogenetic trees. The poorly known fifth species, Billolivia poilanei , would appear to be morphologically more similar in general appearance and calyx characters to the two lowland species but is actually a plant of higher altitude at 1200 m. It is possible that these altitude differences, however, are an artefact of the small number of geographically restricted collections for all five species.

Key to the species

1a. Calyx divided into 5 lobes almost to base; leaf laminas minutely dentate or crenate, often appearing entire; corolla tube 8– 18 mm long, lobes white or white with purple veining (unknown in B. poilanei )................................................................. 2

1b. Calyx connate into a tube at base for at least 4 mm, margin 5-lobed; leaf laminas minutely or conspicuously dentate; corolla tube 20–28 mm long, tips of lobes brightly coloured pink, red or violet................................................................... 4

2a. Calyx lobes> 4 mm wide ........................................................................................................................................ B. poilanei

2b. Calyx lobes <2.5 mm wide.................................................................................................................................................... 3

3a. Leaf abaxially with hairs only on veins or with only occasional hairs on lamina; corolla 12−15 mm long; unfertilised ovary glabrous .............................................................................................................................................................. B. minutiflora

3b. Leaf abaxially with pubescence throughout; corolla 18−25 mm long; unfertilised ovary pubescent at apex B. vietnamensis

4a. Calyx fused into a tube for 7–9 mm; corolla lobe tips pink or red; leaf lamina margins coarsely dentate; petioles 9–18 cm long ................................................................................................................................................................. B. longipetiolata

4b. Calyx fused into a tube for 4–6 mm; corolla lobe tips violet; leaf margins minutely dentate or appearing entire; petioles 6– 12.5 cm long ........................................................................................................................................................... B. violacea