Miyoshiaceae Nakai in J. Jap. Bot. 17: 190. Apr 1941; Miyoshiales Nakai in J. Jap. Bot. 17: 189. Apr 1941; Japonoliriaceae Takht. in Bot. Žurn. 81(2): 85. Mai-Jun 1996; Petrosaviales Takhtajan, Divers. Classif. Fl. Pl.: 577. 24 Apr 1997; Petrosavianae Doweld, Tent. Syst. Plant. Vasc.: lx. 23 Dec 2001

Distribution Eastern China, Japan, Taiwan, Southeast Asia, West and Central Malesia.

Habit Bisexual, perennial herbs. Achlorophyllous holomycotrophic (Petrosavia) or autotrophic (Japonolirion).

Vegetative anatomy Arbuscular mycorrhiza present in both Japonolirion (Paris type of AM) and Petrosavia. Roots fibrous; root stele triarch or tetrach (Petrosavia); root in Petrosavia without medulla; root cortex consisting of four to six layers of parenchyma cells containing fungal hyphae. Phellogen absent. Rhizome with scale-like leaves. Stem vascular bundles forming a cylinder. Vessels present in Japonolirion, usually absent in Petrosavia (roots sometimes containing vessels). Vessel elements with scalariform perforation plates; lateral pits? Imperforate tracheary xylem elements tracheids. Wood rays absent. Axial parenchyma? Sieve tube plastids P2c_cp type, with starch, many cuneate protein crystals and one polygonal protein crystal. Nodes? Calciumoxalate as raphides and druses present in Petrosavia.

Leaves Alternate (spiral), simple, entire, in Petrosavia scale-like, with involute? ptyxis. Stipules absent; leaf sheath short to fairly long. Venation parallelodromous. Stomata anomocytic. Cuticular wax crystalloids? Leaf margin entire.

Inflorescence Terminal (Petrosavia) or axillary (Japonolirion), raceme. Floral prophyll (bracteole) sublateral or absent.

Flowers Actinomorphic, small. Hypogyny (Japonolirion) or almost epigyny (Petrosavia). Tepals 3+3, with imbricate aestivation, petaloid, persistent, free (Japonolirion) or connate at base (Petrosavia); in Japonolirion sepaloid, tepals of outer and inner whorls of slightly different shape. Septal nectaries infralocular. Disc absent.

Androecium Stamens 3+3. Filaments subulate, free from each other and from tepals, in Petrosavia adnate to tepal bases. Anthers basifixed (Japonolirion) or dorsifixed (Petrosavia), non-versatile?, tetrasporangiate, introrse, longicidal (dehiscing by longitudinal slits). Tapetum secretory, with binucleate cells. Staminodia absent.

Pollen grains Microsporogenesis simultaneous. Pollen grains monosulcate, shed as monads, bicellular at dispersal. Exine intectate (Japonolirion) or semitectate (Petrosavia), with columellate infratectum, gemmate (Japonolirion) or reticulate (Petrosavia).

Gynoecium Pistil composed of three carpels connate below or at base only (Petrosavia), or free (Japonolirion); carpel plicate and ascidiate, fused by papillae on septal side; carpel fusion usually postgenital (rarely also congenital). Ovary superior (Japonolirion) or semi-inferior (Petrosavia), trilocular below, unilocular above. Stylodia three, short, recurved (Japonolirion). Stigmas decurrent (Japonolirion) or subcapitate (Petrosavia), type? Pistillodium absent.

Ovules: Placentation dorsal. Ovules usually four (Japonolirion) or numerous (Petrosavia) per carpel, anatropous (in Petrosavia possibly also campylotropous), bitegmic, crassinucellar (or semicrassinucellar). Micropyle endostomal. Outer integument two cell layers thick. Inner integument two cell layers thick. Hypostase not formed. Parietal cell formed from archesporial cell. Integumentary obturator present in Petrosavia. Nucellar cap two cell layers thick, functioning as obturator. Megaspore tetrad T-shaped. Megagametophyte in at least Petrosavia monosporous, Polygonum type. Antipodal cells persistent (Japonolirion). Chalazal chamber not formed. Endosperm development ab initio cellular (in Petrosavia possibly also nuclear?). Endosperm haustoria absent. Embryogenesis?

Fruit A septicidal capsule (Japonolirion) or a follicle with often more or less persistent tepals (Petrosavia).

Seeds Aril absent. Seed coat testal-endotegmic. Testa unwinged (Japonolirion) or winged (Petrosavia). Exotestal cells often collapsed. Endotesta well developed. Exotegmen well developed. Endotegmen crushed. Perisperm not developed. Endosperm copious, oily and proteinaceous. Suspensor formed. Embryo small, in Petrosavia undifferentiated, chlorophyll? Cotyledon one. Radicula poorly developed. Germination?

Cytology n = 12, 13 (Japonolirion); n = 15, 30 (Petrosavia, also tetraploid)

Phytochemistry 3-O-glycosides of 6-C-glycosylquercetin and 6-C-glycosylkaempferol, isoorientin, quercetin-3-O-glycoside (isoquercitrin), quercetin-3-O-arabinoside (avicularin), vicenin-2, orientine, and chlorogenic acid present.

Systematics Petrosavia (3; P. sakuraii: Japan, China, Taiwan, Burma, Vietnam, northern Sumatra; P. sinii: Hainan; P. stellaris: peninsular Thailand, the Malay Peninsula, Borneo, Sulawesi, the Philippines), Japonolirion (1; J. osense; mountains on Hokkaido and Honshu in Japan, on serpentine).

Petrosaviaceae are sister to all monocots except Acorus and Alismatales.

Of the flavonoids investigated, the two flavonol-C-glycosides 6-C-glycosylquercetin-3-O-glycosides and 6-C-glycosylkaempferol-3-O-glycosides are unique to Petrosaviaceae (Iwashina & al. 2005).

The presence of P2c_cp type sieve tube plastids in Petrosaviaceae and Tofieldiaceae is probably a plesiomorphy (Behnke 2000; Cameron & al. 2003). Some species of Velloziaceae (Pandanales) possess a superficially similar type of sieve tube plastids, P2c_ap (Behnke & al. 2000), and Lanaria (Lanariaceae, Iridales) has the type P2c_cps (Behnke 2000).

At least 22 species/phylotypes of Archaesporales, Diversisporales and Glomerales are present in the arbuscular mycorrhiza of Japonolirion, whereas the mycorrhizal specificity is high in Petrosavia (Yamato & al. 2014).

Beccari O. 1871. Petrosavia: nuovo genere di piante parasite della famiglia delle Melanthaceae. – Nuovo Giorn. Bot. Ital. 3: 7-11.

Caddick LR, Furness CA, Stobart KL, Rudall PA. 1998. Microsporogenesis and pollen morphology in Dioscoreales and allied taxa. – Grana 37: 321-336.

Cameron KM, Chase MW, Rudall PJ. 2003. Recircumscription of the monocotyledonous family Petrosaviaceae to include Japonolirion. – Brittonia 55: 214-225.

Engler A. 1897. Liliaceae. – In: Engler A, Prantl K (eds), Nachträge zu II(5), W. Engelmann, Leipzig, p. 72.

Furness CA, Rudall PJ. 1999. Microsporogenesis in monocotyledons. – Ann. Bot. 84: 475-499.

Iwashina T, Kitajima J, Kato T, Tobe H. 2005. An analysis of flavonoid compounds in leaves of Japonolirion (Petrosaviaceae). – J. Plant Res. 118: 31-36.

Krause K. 1929. Zwei für China neue Liliaceengattungen. – Notizbl. Bot. Gart. Mus. Berlin-Dahlem 98: 806-807.

Krause K. 1930. Liliaceae. – In: Engler A (ed), Die natürlichen Pflanzenfamilien, 2. Aufl., Bd. 15a, W. Engelmann, Leipzig, pp. 227-386.

Logacheva MD, Schelkunov MI, Nuraliev MS, Samigullin TH, Penin AA. 2014. The plastid genome of mycoheterotrophic monocot Petrosavia stellaris exhibits both gene losses and multiple rearrangements. – Genome Biol. Evol. 6: 238-246.

Ohashi H. 2000. Petrosavia (Petrosaviaceae) in Taiwan and Hainan. – Taiwania 45: 263-269.

Ohba H. 1984. A review of Petrosavia (Liliaceae), with special reference to the floral features. – J. Jap. Bot. 59: 106-110.

Remizowa M. 2011. Floral morphology in Japonolirion and Petrosavia (Petrosaviales). – Bot. Žurn. 96: 198-214. [in Russian]

Remizowa M, Sokoloff D, Rudall PJ. 2006a. Evolution of the monocot gynoecium: evidence from comparative morphology and development in Tofieldia, Japonolirion, Petrosavia and Narthecium. – Plant Syst. Evol. 258: 183-209.

Remizowa M, Sokoloff D, Rudall PJ. 2006b. Comparative patterns of floral orientation, bracts and bracteoles in Tofieldia, Japonolirion, and Narthecium. – Aliso 24: 157-169.

Remizowa M, Sokoloff D, Rudall PJ. 2006c. Patterns of floral structure and orientation in Japonolirion, Narthecium and Tofieldia. – In: Columbus JT, Friar EA, Porter JM, Prince LM, Simpson MG (eds), Monocots: comparative biology and evolution. Excluding Poales, Rancho Santa Ana Botanical Garden, Claremont, California. – Aliso 22: 159-171.

Stant MY. 1970. Anatomy of Petrosavia stellaris Becc., a saprophytic monocotyledon. – In: Robson NKB, Cutler DF, Gregory M (eds), New research in plant anatomy, Bot. J. Linn. Soc. 63 [Suppl.] 1: 147-161.

Sterling C. 1978. Comparative morphology of the carpel of the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae. – Bot. J. Linn. Soc. 77: 95-106.

Takahashi M, Kawano S. 1989. Pollen morphology of the Melanthiaceae and its systematic implications. – Ann. Missouri Bot. Gard. 76: 863-876.

Takahashi H, Nishio E, Hayashi H. 1993. Pollination biology of the saprophytic species Petrosavia sakuraii (Makino) van Steenis in central Japan. – J. Plant Res. 106: 213-217.

Tamura MN, Takahashi H. 1998. Karyotype analysis of the saprophyte Petrosavia sakuraii (Makino) J. J. Smith ex van Steenis and its systematic implications. – Acta Phytotaxon. Geobot. 49: 49-56.

Tobe H. 2008. Embryology of Japonolirion (Petrosaviaceae, Petrosaviales): a comparison with other monocots. – J. Plant Res. 121: 407-416.

Tobe H, Takahashi H. 2009. Embryology of Petrosavia (Petrosaviaceae, Petrosaviales): evidence for the distinctness of the family from other monocots. – J. Plant Res. 122: 597-610.

Tomimatsu H, Hoya A, Takahashi H, Ohara M. 2004. Genetic diversity and multilocus genetic structure in the relictual endemic herb Japonolirion osense (Petrosaviaceae). – J. Plant Res. 117: 13-18.

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Yamato M, Yagame T, Shimomura N, Iwase K, Takahashi H, Ogura-Tsujita Y, Yukawa T. 2011. Specific arbuscular mycorrhizal fungi associated with non-photosynthetic Petrosavia sakuraii (Petrosaviaceae). – Mycorrhiza 21: 631-639.

Yamato M, Ogura-Tsujita Y, Takahashi H, Yukawa T. 2014. Significant differnence in mycorrhizal specificity between an autotrophic and its sister mycoheterotrophic plant species of Petrosaviaceae. – J. Plant Res. 127: 685-693.

PETROSAVIIDAE S. W. Graham et W. S. Judd

PETROSAVIACEAE Hutch.