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Festuca molokaiensis, a member of the Poaceae (grass) family, is a short-lived perennial clumping grass. It is a cespitose (growing in dense, low tufts) with culms (the aerial stem of a grass) 60 to 70 cm (1.9 to 2.3 ft) tall, scabrous (having a surface that is rough to the touch) below the panicle (a branched, indeterminate inflorescence with spikelets (a small unbranched, indeterminate inflorescence with flowers attached directly by its base without a stalk that are arranged along the axis) born upon the secondary branches). Leaf sheaths (a tubular structure that partly or wholly surrounds the stem) with margins fused for 1 to 2 mm (0.04 to 0.08 in) at base, and ligules 1.5 to 2.5 mm (0.06 to 0.1 in) long, glabrous. Leaf blades are flat and smooth, 34 cm (13 in) long, and about 2 mm (0.08 in) wide. Inflorescences are panicles that are 8.5 to 13 cm (3 to 5 in) long, with approximately 75 spikelets. Spikelets are located at the ends of the branches, 5- to 6-flowered, broadly lanceolate, pale green. Glumes (a pair of small bracts found at the base of the spikelet) are lanceolate, green. The lemmas (the lower bract of the floret of a grass) are scabrous throughout, 5 to 6 mm (0.2 to 0.24 in) long. Awns (a stiff bristle) are 1.5 to 2.8 mm (0.06 to 0.11 in) and anthers (the part of a stamen that contains the pollen) are 2.8 to 3 mm (0.11 to 0.12 in) long. The caryopsis, or a small one-seeded dry indehiscent fruit in which the fruit and seed fuse in a single grain, was not observed and thus not included in the description of the species by Catalán et al. (2009).

The species historical range included Hawaii. See below for information about where the species is known or believed to occur.

Habitat Requirements

Festuca molokaiensis occurred at 880 m (2,887 ft) on steep slopes in mesic forest. Associated native species include Metrosideros spp., Coprosma spp., Leptecophylla tameiameiae, Dodonaea viscosa, Alyxia stellata, Viola spp., Melicope spp., Myrsine spp., Diospyros sandwicensis, Dryopteris spp., Phyllanthus distichus, Luzula hawaiiensis var. glabrata, Selaginella spp., and Carex spp.

Food Habits

Movement / Home Range

Festuca molokaiensis is known only from Kupaia Gulch on Molokai. In 2014, a field survey was conducted at Kupaia Gulch where the type specimen was collected; yet no individuals were found. Following that survey, efforts to find F. molokaiensis continue to be conducted by botanists of the Molokai Plant Extinction Prevention Program who perform surveys at Kupaia Gulch annually; no plants have been found

Reproductive Strategy

As a grass species, Festuca molokaiensis is assumed to be wind pollinated. The holotype collected in April 2007 contained flowers and seeds. Comparing the flowering and fruiting periods of Festuca aloha, a close relative from the Hawaiian islands, F. molokaiensis may also flower during the months of March and April and fruit in May. Seed viability and germination conditions are unknown. It is unknown whether a soil seed bank remains within the limited geographic range of the species. A study by Sakai et al. (1995) was used to make inferences on the breeding system of Festuca molokaiensis. Sakai et al. (1995) studied the colonists of the flora of the Hawaiian Islands to determine the breeding system of the colonist’s lineage, the assumed breeding system of the colonist, the breeding system of the current species, the assumed pollinator of the colonists, and the assumed dispersal method. At the time of the study, only one species of Festuca was derived from that colonist. According to Sakai et al. (1995) the breeding system of the colonist’s lineage for the genus Festuca was monomorphic, the assumed breeding system of the colonist was hermaphroditism, and the breeding system for Festuca hawaiiensis (the only known Festuca species in Hawaii at the time of the study) was hermaphroditism. The assumed pollinator of the colonists was wind and the assumed original long-distance dispersal method was by birds via barbs. The fruit of Festuca are dry. Based on this study, we can assume that the breeding system for F. molokaiensis is hermaphroditism, which means it is capable of both sexual and vegetative reproduction.

Other

The morphological similarities between Festuca molokaiensis and F. hawaiiensis include similar ligule (small, membranous attachment jutting from the top on the inner side of the leaf at the junction of the blade and sheath) size and shape, ovary hairiness, and leaf-blade anatomy. Festuca hawaiiensis differs from F. molokaiensis in that it is a larger plant and occurs at higher elevations (2,000 m; 6,562 ft) on the island of Hawaii. A genetic study was conducted by Catalán et al. (2009) on one sample of Festuca molokaiensis from Molokai and two samples of F. aloha from Kauai. The results of the study revealed that all three samples clustered with each other in the “broad-leaved Festuca clade”. It also revealed that F. aloha formed a monophyletic group that descended from a common evolutionary ancestor and that it was sister to F. molokaiensis. The analysis also showed that there are molecular differences between the two samples of F. aloha from Kauai and from the sample of F. molokaiensis; which in turn validates the taxonomic separation of the two species. Based on this analysis, the closest relative of Festuca molokaiensis is F. parvigluma from eastern Asia and the next closest relative is F. subulata from northwestern North America.