Taxonomy
Doryopteris majestosa leaf blade with proliferous buds © Paulo Windisch
Doryopteris majestosa is 1 of approximately 40 species comprising the genus Doryopteris.
The genus is mostly encountered in the Neotropics, with just a couple of species occurring in the Hawaii Islands and in South Africa. Only one species - D. concolor (Langsd. and Fisch) kuhn, has pan-tropical distribution.
Full taxonomic treatment of the genus is being prepared for publication.
Morphology
Doryopteris majestosa is a magnificent species of fern. Its large and variously lobed fronds are the most notable features. They vary in shape from:
- sagittate
- 3-5-lobate
- pedate
- broadly pinnatilobed
Sub-dimorphic fronds grow from the decumbent rhizome in D. majestosa:
- fertile fronds are up to 80cm long - the fertile sori occur alongside the margin of the lamina
- sterile fronds are smaller and grow up to 46cm long
In both types of fronds, petioles are brown to dark brown and basically circular in cross-section. On the upper side they are covered with rust-coloured hairs, which tend to be concentrated towards the base of the lamina.
Proliferous buds are present on both sterile and fertile fronds at the base of the lamina.
Look-alikes
D. majetosa was formerly known and often identified as, D. nobilis.
The 2 species are the largest species of the genus and have similar leaf architecture.
However, while revising the genus, it was noticed that the type specimen of D. noblis and all its synonyms did not bear buds.
Thus, specimens that have proliferous buds and a number of other distinct characters have been separated as a distinct taxon known as D. majestosa.
Other main characters distinguishing D. majestosa from D. nobilis are:
- size - it is bigger than D. nobilis
- spores - whitish with crest of numerous thread-like appendages (golden, with fewer and plate-like appendages in D. nobilis)
- cytology - D. majetosa is triploid, while D. nobilis is diploid
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Glossary
Decumbent
Sub-erect (erect meaning vertical).
Diploid
With two sets of chromosomes in each cell.
Fertile frond
Frond that produces spores.
Frond
Leaf of a fern or palm.
Lamina
Leaf blade.
Neotropics
The tropical part of the American continents, such as central Mexico, the Caribbean islands, northern Chile, Paraguay and southern Brazil.
Pantropical
Occurring in all the tropical regions of the world.
Pedate
Palmetely lobed, but with the side lobes further divided successively, one from the other (not all arising from the same point as in palmate).
Petiole
Leaf stalk.
Pinnatilobed
Pinnately divided, with unspecified depth of division.
Proliferous buds
Buds capable of forming another plant.
Rhizome
Modified stem.
Fupicolous
Growing on or amongst rocks.
Sagittate
Shaped like an arrow-head.
Sori (plural of sorus)
Cluster of sporangia.
Sporangia (plural of sporangium)
Spore-producing structure in pteridophytes.
Sub-dimorphic
Having 2 different shapes, forms or size.
Triploid
With 3 sets of chromosomes in each cell.