Myriopteris intertexta, formerly Cheilanthes intertexta,[1] is a species of lip fern known by the common name coastal lip fern. It is native to montane California and western Nevada, Oregon east of the Cascades, and with a disjunct population in central Utah. It grows in dry rocky habitats in sun, typically in rock cracks with little or no soil.
This fern produces clusters of dark green leaves up to about 25 centimeters long. Each leaf is divided into bumpy segments which are subdivided into pairs of rounded beadlike ultimate segments with their edges curled under to make them concave underneath. Each ultimate segment is less than 3 millimeters wide, sparsely hairy on top and scaly on the underside. Its sori are mostly hidden under the scales and curled leaflet margin (false indusium). The long-lanceolate scales on the underside of the leaflets are approximately 1 mm wide at their base, intermediate between those of its two parents (M. gracillima scales are very narrow (hair like) and those of M. covillei are 2–3 mm wide). The leaves arise from a short creeping rhizome, such that plants often have an elongated base, for example creeping along a rock crevice.[1]
M. intertexta is found in Oregon, California, and eastern Nevada. In addition, there is an apparently disjunct population in north-central Utah on Mount Olympus in the Wasatch Range. The range of M. intertexta is intermediate between that of its two parents M. gracillima (with a range that extends further north) and M. covillei (with a range that extends further south and east into southern California, Arizona, and the Baja California peninsula and central Mexico).[1] [2] [3]
Myriopteris intertexta was first described by William Ralph Maxon in 1918, as Cheilanthes covillei subsp. intertexta, based on material collected on Black Mountain by William Russel Dudley. In 1923, Maxon elevated it to the level of a full species as Cheilanthes intertexta in his treatment of ferns for LeRoy Abrams' Illustrated Flora of the Pacific States.
The development of molecular phylogenetic methods showed that the traditional circumscription of Cheilanthes, including that used by Maxon, is polyphyletic. Convergent evolution in arid environments is thought to be responsible for widespread homoplasy in the morphological characters traditionally used to classify it and the segregate genera that have sometimes been recognized. On the basis of molecular evidence, Amanda Grusz and Michael D. Windham revived the genus Myriopteris in 2013 for a group of species formerly placed in Cheilanthes. One of these was C. intertexta, which thus became Myriopteris intertexta.
In 2018, Maarten J. M. Christenhusz transferred the species to Hemionitis as H. intertexta, as part of a program to consolidate the cheilanthoid ferns into that genus.
This fern is thought to be an allotetraploid fertile hybrid of Myriopteris gracillima (maternal) and Myriopteris covillei (paternal).[1] [4]
. LeRoy Abrams . An Illustrated Flora of the Pacific States . I . 1923 . Stanford University Press . California .