Botrychium hesperium (Western Moonwort)
Ophioglossaceae (Adder's Tongue Family)

Montane, subalpine, alpine. Meadows, disturbed areas. Summer, fall.
Above: Cross Mountain Trail, August 5, 2019.
Left: Molas Pass, August 18, 2011.

Botrychium hesperium is distinguished by its slightly stalked trophophore, ovate (not parallel-sided) basal pinnae which are asymmetrically enlarged on the lower side, by the often entire or sometimes shallowly dissected pinnae above the basal pair, and by the blush of orange-pink on one side of the common stalk.  As clear as this may sound, in real life it is not.  The species can be quite difficult to distinguish from the very similar B. pinnatum.

The plants shown may be most correctly classified as Botrychium hesperium variety fenestratum, because of the wide spacing between each row of pinnae.

As the top photograph illustrates, the real Botrychium challenge is finding, not identifying them. The plant in the above two photographs is just 1 1/2 inches tall. The top photograph is taken from a height of about two feet, so from a height of 5 or 6 feet the plant would look like a large green dot in the midst of much larger leaves.

Botrychium hesperium was at first named Botrychium matricarifolium subsp. hesperium by Maxon & Clausen. Wagner & Lellinger renamed it Botrychium hesperium.

Click for Don Farrar's page on B. hesperium. 

Botrychium hesperium (Western Moonwort)
Ophioglossaceae (Adder's Tongue Family)

Montane, subalpine, alpine. Meadows, disturbed areas. Summer, fall.
Molas Pass, August 18, 2019.

Notice that the basal pinnae are ovate but deeply lobed whereas the upper pinnae are very slightly lobed or entire.  The trophophore has a very short stalk just above the joint where it meets the sporophore (but this is difficult to see in my photographs).

The sporophore is short-stalked, three parted, and longer than the trophophore.

Botrychium hesperium (Western Moonwort)
Ophioglossaceae (Adder's Tongue Family)

Montane, subalpine, alpine. Meadows, disturbed areas. Summer, fall.
Cross Mountain Trail, August 30, 2019.

These two B. hesperium were growing about a foot apart, each to a height of about 4 inches.

Within 20 feet were a number of diminutive B. hesperium, all just slightly more than 1 inch tall.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Botrychium hesperium