[Boraginaceae+Vahlia+[Rubiales+[Plantaginales+Solanales]]]
Vahliales Doweld, Tent. Syst. Plant. Vasc.: xlviii. 23 Dec 2001; Vahlianae Doweld, Tent. Syst. Plant. Vasc.: xlviii. 23 Dec 2001
Genera/species 1/>5
Distribution Tropical and southern Africa, Madagascar, Egypt to India and Sri Lanka.
Fossils Unknown.
Habit Bisexual, annual, biennial, or perennial herbs (sometimes suffrutices). Densely glandular-hairy.
Vegetative anatomy Phellogen ab initio epidermal. Vessel elements with simple perforation plates; lateral pits?, simple pits. Imperforate tracheary xylem elements tracheids, libriform fibres and fibre-tracheids. Wood rays uniseriate. Axial parenchyma absent. Sieve tube plastids Ss type. Nodes 1:1, unilacunar with one leaf trace. Calciumoxalate crystals?
Trichomes Hairs multicellular, uniseriate, non-glandular or glandular.
Leaves Opposite, simple, entire, with ? ptyxis. Stipules and leaf sheath absent. Petiole vascular bundle transection arcuate. Venation pinnate. Stomata anomocytic, anisocytic or paracytic. Cuticular wax crystalloids? Leaf margin entire.
Inflorescence Flowers pairwise in terminal or axillary cymes.
Flowers Actinomorphic, small. Epigyny. Sepals five, with valvate aestivation, persistent, at least usually free (occasionally connate?). Petals five, with imbricate aestivation, free. Nectariferous disc intrastaminal.
Androecium Stamens five, haplostemonous, antesepalous, alternipetalous. Filaments subulate, free from each other and from tepals, inserted at margin of nectariferous disc. Anthers dorsifixed, usually versatile, tetrasporangiate, introrse, longicidal (dehiscing by longitudinal slits). Tapetum secretory?, with binucleate cells. Staminodia absent.
Pollen grains Microsporogenesis simultaneous. Pollen grains tricolporate, shed as monads, bicellular at dispersal. Exine semitectate, with columellate infratectum, reticulate, striate.
Gynoecium Pistil composed of two (or three) connate carpels. Ovary inferior, unilocular. Stylodia two (or three), free, diverging. Stigmas carinal, capitate, type? Pistillodium absent.
Ovules Placentation apical, pendulous, with confluent placentae. Ovules numerous per ovary, anatropous, pendulous, bitegmic, tenuinucellar. Micropyle endostomal. Outer integument two or three cell layers thick. Inner integument two or three cell layers thick. Parietal tissue one cell layer thick. Endothelium differentiated. Megagametophyte monosporous, Polygonum type. Antipodal cells persistent. Endosperm development cellular. Endosperm haustorium chalazal. Embryogenesis onagrad.
Fruit A septicidal capsule, dehiscing at apex, with persistent calyx.
Seeds Aril absent. Raphe disappearing during seed maturation. Exotestal cells more or less elongate, with outer wall or all walls thick. Endotesta one cell layer thick; cells with well developed U-shaped thickenings, non-lignified. Tegmen? Perisperm not developed. Endosperm sparse, two cell layers thick, with lipids and aleuron grains. Embryo straight, chlorophyll? Cotyledons two. Germination phanerocotylar?
Cytology n = 6, 7, 9
DNA
Phytochemistry Flavonols (kaempferol, quercetin), kaempferol glycosides (afzelin, astragalin), quercetin glycosides (quercitrin, isoquercitrin, rutin), vahlia biflavone, Route I iridoids, triterpenes, terpenoids, gallic acid, coumarins (umbelliferone, scopoletin, scoparone), chiro-inositol (cyclohexanehexol), and dulcitol (galactose-based hexitol) present.
Use Unknown.
Systematics Vahlia (>5; V. capensis, V. dichotoma, V. digyna, V. geminiflora, V. somalensis; tropical and southern Africa, northern Madagascar, Egypt, Iran, India, Sri Lanka).
The sister-group relationship of Vahliaceae is not clarified. They may be sister to Lamiales or Boraginaceae (Bremer & al. 2002). Some ndhF analyses even indicate a position within Solanales. They are provisionally kept as a separate lineage at the base of the Lamiidae crown clade.
Literature
Bridson DM. 1975a. A revision of the family Vahliaceae. – Kew Bull. 30: 163-182.
Bridson DM. 1975b. Vahliaceae. – In: Polhill RM (ed), Flora of tropical East Africa, Crown Agents for Oversea Governments and Administrations, London, pp. 1-6.
Bridson DM. 1978. 64. Vahliaceae. – In: Launert E (ed), Flora Zambesiaca 4, Flora Zambesiaca Managing Committee, London, pp. 48-53.
Engler A. 1891. Saxifragaceae. – In: Engler A, Prantl K (eds), Die natürlichen Pflanzenfamilien III(2a), W. Engelmann, Leipzig, pp. 41-93.
Engler A. 1930. Saxifragaceae. – In: Engler A, Harms H (eds), Die natürlichen Pflanzenfamilien, 2. Aufl., Bd. 18a, W. Engelmann, Leipzig, pp. 74-226.
Erbar C, Leins P. 2011. Synopsis of some important, non-DNA character states in the asterids with special reference to sympetaly. – Plant Div. Evol. 129: 93-123.
Gornall RJ, Al-Shammary KIA. 1998. Vahliaceae. – In: Cutler DF, Gregory M (eds), Anatomy of the Dicotyledons 4, Clarendon Press, Oxford, pp. 232-235.
Hamel JL. 1953. Contribution à l’étude cyto-taxinomique des Saxifragacées. – Rev. Cytol Biol. Vég. 14: 113-313.
Inamdar JA, Patel RC. 1971 [1972]. Structure and development of trichomes, stomata and systematic position of Vahlia digyna (Retz.) O. K. – Acta Bot. Hung. 17: 361-369.
Kadereit JW, Bittrich V (eds). 2016. The families and genera of vascular plants XIV. Flowering plants – eudicots – Aquifoliales, Boraginales, Bruniales, Dipsacales, Escalloniales, Garryales, Paracryphiales, Solanales (except Convolvulaceae), Icacinaceae, Metteniusaceae, Vahliaceae. Springer, 412 pp.
Majinda RRT, Motswaledi M, Waigh RD, Waterman PG. 1997. Phenolic and antibacterial constituents of Vahlia capensis. – Planta Medica 63: 268-270.
Nemirowich-Danchenko EN. 1996. Vahliaceae. – In: Danilova M (ed), Anatomia seminum comparativa. Rosidae I. Vol. 5: 73-76, Mir et Semja, St. Petersburg.
Polevova SV. 2006. Review of the sporoderm ultrastructure of members of the Asterales. – Paleontol. J. 40 Suppl. 5: S656-S663.
Raghavan TS, Srinivasan VK. 1942. A contribution to the life history of Vahlia viscosa Roxb. and V. oldenlandioides Roxb. – Proc. Indian Acad. Sci., Sect. B, 15: 83-105.
Rangaswami AK. 1971. Cytology of Vahlia oldenlandioides. – Proc. Indian Sci. Congr. 53: 469.
Saxena NP. 1973. Studies in the family Saxifragaceae 8. Floral anatomy, seed development and systematics of Bistella Adans. – J. Indian Bot. Soc. 52: 244-251.