Pyrrosia piloselloides (L.) Presl, Polypodiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 6 (Go to the risk assessment)

Other Latin names:  Drymoglossum piloselloides (L.) C. Presl; Pteris piloselloides L.

Habit:  fern

Description:  "Rhizome shortly elongated, not grooved ventrally, 4-4.5 mm thick, phyllopodia to 1-2 cm apart, lateral buds situated on the phyllopodia.  Anatomy: ground tissue sclerenchymatous, sclerenchyma sheath and sclerenchyma strands absent; vascular strands 9-11.  Scales basifix, 3-10 mm long, base often ciliate, with several stalked marginal glands; acumen brown, entire, shorter scales interspersed with he larger ones present.  Fronds monomorphic, not or indistinctly stipitate; stipes up to 13 cm; lamina, index 7-20; widest above the middle, 26-111 x 2.5-7.3 (-10) cm, base very gradually narrowed, apex acuminate.  Venation:  secondary veins distinct, with the tertiary veins forming regular areoles; included veins much branched and strongly anastomosing; free veins many, pointing to all directions.  Hydathodes distinct, scattered over the lamina, ± superficial.  Anatomy:  stipe or lower part of costa with central bundle of collenchyma and 7-8 central and 3-5 lateral vascular strands; lamina ± 0.3 mm thick, upper epidermis with flat cells with thickened walls, hypodermis composed of a single cell layer, water-tissue absent, palissade and spongy parenchyma little different, lower epidermis with thickened cell walls, stomata superficial, pericytic.  Indument dimorphic, a dense mat, persistent, greyish brown; upper layer composed of hairs 0.4-1.9 mm in diameter, with appressed, narrowly boat-shaped to acicular rays, appressed to a lower layer composed of hairs with mainly woolly rays.  Seri apical, in a more or less sharply defined patch, closely packed, superficial; many irregularly scattered through each soriferous areole, situated on short side branches of the included veins, not confluent; * 0.5 mm in diameter; developing from the apex downwards, when old individually distinct, exserted from the indument.  Sporangia sessile or on stalks up to 1/4 x as long as the capsule, capsule 0.3-0.4 mm high, with 12-14 indurated annulus cells.  Paraphyses not differentiated.  Spores (52-) 59.2-63.6 (-68) x (28-) 34.4-39.0 (-40) µm, smooth"  (Hovenkamp, 1986; p. 222).

Habitat/ecology:  "Epiphytic (to 40 m high) or epilithic, preferentially on limestone.  Sea level to 600 m"  (Hovenkamp, 1986; p. 222).

Propagation:  Spores

Native range:  India, southern China, southeast Asia (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Lau, Alex/Frohlich, Danielle (2012) (p. 21) Voucher cited: OED 2008101703 (BISH)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 74) Common
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Additional information:
Additional online information about Pyrrosia piloselloides is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Pyrrosia piloselloides as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Pyrrosia piloselloides may be available from the Germplasm Resources Information Network (GRIN).

References:

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Hovenkamp, P. 1986. A monograph of the fern genus Pyrrosia (Polypodiaceae). Leiden University Press (Leiden Botanical Series, Vol. 9). 280 pp.

Lau, Alex/Frohlich, Danielle. 2012. New plant records from O‘ahu for 2009. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2011. Part II: Plants. Bishop Museum Occasional Papers. 113:7-26.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.