Schizaeaceae

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Schizaeaceae

Distribution

Africa: present Chile: present Japan: present Mascarene Islands: present New Zealand: present S. Africa: present Southern India: present Southern and Eastern Africa: present U.S.A: present pantropic with a few outlying species of both in temperate regions: present tropical America: present
The Malaysian genera Schizaea and Lygodium are pantropic with a few outlying species of both in temperate regions (U.S.A., S. Africa, Chile, Japan, and New Zealand). Anemia has its main distribution in tropical America, with a few species in Africa and one in southern India. Mohria is confined to southern and eastern Africa and the Mascarene Islands.

Anatomy

The fullest account of anatomy in the family is by Prantl (l.c.); later works are cited by Bower. The rhizome of Lygodium has a solid protostele; the rachis of the climbing frond has also a compact vascular Strand (not C-shaped), with very large tracheids in the xylem, no doubt in adaptation to its habit (a slender twining rachis carrying many leaflets, which thus needs a vascular system of capacity large in proportion to its area of cross-section). The rhizome of Schizaea has a more or less medullated protostele, and the stipe has a small compact vascular Strand in which the xylem is reduced, more or less 3-armed as seen in cross-section. In both genera there is considerable development of sclerenchyma. The genera Anemia and Mohria have a more complex vascular anatomy. Schizaea shows specialization in the arrangement of stomata, the details of this varying from species to species.

Taxonomy

The early history of the taxonomy of the genus Lygodium is very complex, for various reasons. Linnaeus began badly by including references to three distinct species under his Ophioglossum scandens (the basis of Lygodium scandens Sw.); and he was unfortunate in having a poor specimen of a sterile frond of an immature plant on which to base his O. flexuosum. In the years immediately following 1800, several authors were independently studying specimens of Lygodium, and the following generic names were given: Lygodium Sw., Ugena Cav., Ramondia Mirbel, Odontopteris Bernh., Gisopteris Bernh. and Hydroglossum Willd. (all in 1801), Cteisium Michx (1803) and Vallifilix Thouars (1809). The following names were also given to Schizaea: Lophidium Rich. (1792) and Ripidium Bernh. (1801). For a full bibliographic Statement on these genera, and a discussion of their typification, see .

In the case of Lygodium, there is so much variation in leaflet-form, due to (a) age of plant, (b) environmental conditions, (c) height above ground from which specimen is taken, (and probably also to polyploidy and hybridization) that, even with ample material, it is not easy to define specific limits, and there was much confusion in the use of names by earlier authors. Different forms of the same species reeeived different names, while in other cases two quite different species were confused under one name. Willdenow based his Hydroglossum pinnatifidum on two specimens, one sterile and one fertile, belonging to two quite distinct species, and his name, transferred to Lygodium, was subsequently used by different authors for both these species. For a detailed discussion of this subject, see .

The only good monograph of the whole family is that of Prantl (l.c., 1881), whose very thorough morphological study (of material then available) laid a sound basis on which others, working on various aspects of the family and with new material, could build. Diels (in Engler, Pflanzenfam.) followed Prantl with little alteration, as did also Christensen (Index Filicum, 1905). As regards nomenclature, Prantl did not look fully into the typification of L. scandens (L.) Sw. and he did not follow some of our modern rules. Also he did not have good material (in a few cases he had no material) of some of the less common Malaysian species.

Nakai published a survey of the whole family in 1937 (). He devided it into the three families Schizaeaceae, Lygodiaceae and Anemiaceae (including Mohria in the last) and also raised some infra-generic groups to generic rank. This process was carried further by C. F. Reed () who raised the rank of the whole group to that of an Order, Schizaeales, with families for the fossil as well as living representatives. He separated Mohria as a family distinct from Anemia, and raised further subdivisions of Lygodium and Schizaea to generic rank, but made no critical contribution to the understanding of species, nor any new basic morphological study. Copeland () made little change from Christensen's arrangement.

Cytology

The only records are by Manton & Sledge () and Lovis (). Lygodium scandens (L. microphyllum of present work) in Ceylon had n = 30. L. circinnatum in Ceylon had n = 58, but a plant in cultivation at Kew had n = 29. A plant of L. japonicum at Kew also had n = 58. The basic number in Anemia is 38; a naturalized plant in Ceylon was tetraploid, a plant in cultivation at Kew diploid. Schizaea asperula Wakef. in New Zealand had n = 77 (Lovis, l.c.); the same number was also found by Lovis (unpublished) for S. dichotoma in New Zealand. In Ceylon Lovis found that S. digitata had a very high number (n = 325 ± 30). These figures indicate that polyploidy is not uncommon in the family, and that the extreme reduetion of plant-form in Schizaea may be associated with high polyploidy.

Uses

The tough slender climbing rachises of Lygodium find various uses, either in their natural form, or prepared by Splitting for finer purposes. They are used as a Substitute for cord (e.g. for tying sheaves of rice), for plaiting into hats, bracelets, etc., for fastening the rims of sieves, and in other ways. There are records of the use of several species of Lygodium, and also of Schizaea dichotoma, for a great variety of medicinal purposes (see ; also ), but no critical study of such uses has been made. Very young leaves of Lygodium microphyllum and L. circinnatum are eaten in Java (). The plants are also used (especially Lygodium) in magical ceremonies connected with house-building, rice culture, fishing, etc.