Anogramma
Anogramma (L.) Link, or the "Annual Fern" as it may be referred to, is a genus which now has ten species proposed, with these having a worldwide distribution. Within Australia however, Anogramma Leptophylla is the only recognised native species, with this being found in all states and territories except for QLD, NT and the ACT (Atlas of Living Australia, n.d.).
The genus is characterised by its short tuberous gametophytes which are perennials and the sporophytes being annuals, with the fronds described as deciduous (McCarthy, 1998). The Anogramma is often mistaken for young Cheilanthes austrotenuifolia plants, as these have a similar appearance and distribution in Australia (Threatened Species Section, 2008).
Anogramma Leptophylla is not currently considered to be threatened in Western Australia, though it is listed as vulnerable in Tasmania and as rare in South Australia.
Current IUCN status: Not Evaluated
Regarding species from outside Australia, the most threatened is the Anogramma ascensionis (Ascension Island Parsley Fern) which is considered as critically endangered on the IUCN Red List.
Threats for the genus include; land clearing, competition from introduced species, trampling by agricultural stock, as well as damaging fire regimes (Threatened Species List, 2008).
Anogramma can be most often found among moist rocky outcrops and crevices, as well as among earth banks of a variety of forest types, with it often being surrounded by moss or humus. The prothallus is found to be a tuber like structure and it is from this the rhizomes are adjoined. The rhizomes are very short and erect with scales at their base which graduate into the reddish/rust coloured hairs that run along it. The stipe of the plant grows up to 5cm and has a few small scales at its base. The remainder of the stipe however is shiny and free of hairs. Anogramma’s frond can have two different morphologies either standing erect, or otherwise spreading. There are two distinctive types of fronds with these either fertile or sterile. The size of the fertile fronds can range from 2.5 up to 12 cm and the sterile only up to 4cm. The sterile fronds may also display an irregular fan shape. The lamina can grow up to 5cm long and 3cm wide and have rounded pinnae, these are the primary divisions of the frond. The pinna, or the individual leaf sections, are joined with deep lobes and have a wedge-shaped base that then turns into straight sides at its stalk. The veins on these leaflets are in a forked arrangement. The sporangia are grouped into what are called sori, these are found clustered along the surface veins. As the sori become mature, these clusters may become even more defined. The sori of Anogramma are not contained within a protective covering known as an indusium. The spores of the sporangia join together in groups of four. The individual spores are black in colour exhibit what appears to be a three-pronged scar, with this feature known as a trilete (McCarthy, 2008).
Anogramma is a genus of homosporous ferns, meaning each plant produces only one type of spore (Nakazato & Gastony, 2003). It is an annual fern in which the sporophyte will die off during hotter months, the gametophyte, or prothallus, can survive these periods however. As a result of this they usually prefer to grow in regions with alternating wet and dry seasons. In regards to ploidy level, the Australian species Anogramma Leptophylla has a haploid number of 26 chromosomes. All species of this genus are terrestrial plants (McCarthy, 1998).
Relatively little work has been done on the evolution of this genus. However one study has shown that Anogramma may be a polyphyletic group (See Figure 1. in media). This means that members of the genus have arisen from more than one ancestor. With results based on rbcL sequences, it was shown that Anogramma Leptophylla was more closely related to Cosentinia Vellea than it is to some other members of the genus (Nakazato & Gastony, 2003).
Working Classification
Kingdom - Plantae
Phylum - Charophyta
Class - Equisetopsida
Subclass - Polypodiidae
Family - Pteridaceae
Genus - Anogramma
See media files for distribution map of W.A.
Anogramma leptophylla can be found in a range of shady and moist habitats. Such as among crevices or on rock ledges, like granite outcrops for example, as well as earth banks within forested areas. It prefers to grow in or around humus, or highly organic soil. It has also been noted that moss plants are a characteristic vegetation type within A. leptophylla habitats (McCarthy, 1998).
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