Woodwardia prolifera

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Woodwardia prolifera

Description

Plants terrestrial.

Distribution

Asia-Temperate: China Southeast (Fujian present); Taiwan (Taiwan present), Asia-Tropical: Philippines (Philippines present), Bataan Islands present, Guandong present, island of Kyushu present, ldzu Peninsula of Honshu present
ldzu Peninsula of Honshu and the island of Kyushu, west to Fujian and Guandong Provinces of China, south to Taiwan; in Malesia: Philippines (Bataan Islands), nearly confined to coastal regions.

Taxonomy

Gray stated that Beechey’s plants are in Arnott’s herbarium, which is now deposited at E (). Since W.J. Hooker was in residence at Glasgow during the preparation of their work on Beechey’s Voyage, I interpret the specimen at GL, now deposited at E, as holotype of W. prolifera. Nakai cited two collections in his description of W. exaltata. I choose the collection annotated Hachijo Island, Toichi Asai s.n. (TI) as lectotype of the species.

Cytology

n = 34.

Notes

1. With its drooping fronds, lustrous lamina, and numerous leafy laminar buds, W. prolifera is arguably the showiest species in the genus. It is frequently cultivated, especially in glass houses and conservatories, where it thrives. It can be grown outdoors where winter frosts are absent or very light, such as coastal California and peninsular Florida. It adapts particularly well to indoor and greenhouse culture, but requires a large amount of space.
2. The variability of pinnae dissection, blade texture and extent of vivipary in W. prolifera has prompted workers to describe a number of segregate taxa. Although the variation can be considerable, it appears to be fairly continuous. There is, however, a tendency to produce more strongly asymmetric pinnae toward the southern and eastern portions of its range. Specimens from Japan (e.g., Tagawa 7934) and mainland Asia (e.g., Chang 48411, Lau 4230) produce few gemmae and bear pinnae having only a few of the inferior, basalmost lobes reduced. Material from Taiwan (Huang 2328), the Ryukyu Islands (Conover 1825) and The Philippines (Fenix 3773) are more frequently proliferous and bear pinnae having several to many of the inferior, basalmost pinnae absent or otherwise reduced to a narrow wing. Other features, such as narrowing of the lobes and pinnae and involution of the laminar margins, show a similar but less well-marked trend.
3. Ching (in Chiu 1974) proposed var. formosana for plants exhibiting the morphological extreme in which the inferior, basalmost pinnae lobes are absent. Although of striking appearance in the extreme, one can cite numerous specimens varying in the degree to which these lobes have been reduced in size or eliminated altogether. Further, there are no other characters or features to suggest that W. prolifera comprises two or more identifiable monophyletic subpopulations that may be proposed as subspecies or varieties. As with all other Asian species of Woodwardia, careful field studies and more collections are needed.
4. The origin and differentiation of the laminar gemmae is not understood. Do they represent dormant remnants of the laminar marginal meristem? Or do they arise ‘de novo’ at a later developmental stage of the lamina. It is, however, clear that the distribution of buds along the adaxial laminar surface is not random. Rather, they always occur above and proximate to primary areoles. Unlike the rachial buds of W. radicans and W. unigemmata, the laminar buds of W. prolifera disarticulate freely from the fronds, leaving a smooth, nearly round saucer-shaped indentation. Whereas rachial buds produce several well-developed fronds and a number of roots while still attached to the parent plant, laminar buds produce but a single frond and no roots while attached to the parent.

Citation

Cranfill 2001: Phylogenetic studies in the Polypodiales (Pteridophyta) with an emphasis on the family Blechnaceae: 208. unpubl. thesis, Berkeley.