Vascular Plants of the Gila Wilderness
Presented in Association with the
Western New Mexico University Department
of Natural Sciences
Key to the genus Astrolepis in the Gila National Forest
The members of the genus Astrolepis are usually found in direct sunlight among rocks, and all therefore prefer south or southwest facing exposures. There is overlap in the preferred habitats, so that more than one species frequently is found in an area. All species are commonly found on limestone substrates. They are once pinnate and have marginal
sporangia. Accurate identification requires that the adaxial scales by examined with magnification. There are only four species of Astrolepis (as they are currently defined) found in the United States, and all four are found in the Gila National Forest. The strategy for keying this genus was adapted from the Flora of North America.
|1. Longest pinnae very small, usually about 5mm and no longer than 7mm in length; adaxial (topside) scales are broad like a shield with
cilia coming off the edges.....Astrolepis cochisensis.||1. Longest pinnae longer than 7mm, adaxial scales attached at the end and elongate .....2.||
||2. Largest pinnae asymmetrically lobed or nearly entire, adaxial scales so dense
that the adaxial surface looks bluish gray, most fronds less than 25cm tall.....Astrolepis integerrima.
||2. Largest pinnae are symmetrically lobed, apparent color of pinnae not influenced by the scales, fronds
frequently over 25cm tall.....3.
||3. Pinnae very shallowly lobed, so as to appear nearly entire; adaxial scales deciduous and sparse, but those
remaining are 2-4 times as thick as the cilia.....Astrolepis windhamii.
||3. Pinnae noticably lobed, sometimes markedly; the few adaxial scales that remain on mature fronds are about as thick as the cilia.....Astrolepis sinuata.
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