Selaginella underwoodii

Selaginella underwoodii Hieronymus

By Elisabeth Alden, AZ Native Plant class, summer 2005

Common names: Spike moss, little club moss, Underwood’s spikemoss

Family: Selaginellaceae

Synonym: Selaginella fendleri (L. Underwood) Hieronymus 1900 not Baker 1883 (1)

Etymology: Diminutive of Latin, Selago, an old name for a club moss (3).

Identification

Growth form: Plants are normally terrestrial, on rock.

Roots: Rhizophores borne on upper side of stems, throughout stem length, 0.15-0.27(-0.3) mm diameter. Roots branching several times dichotomously from rhizophore tips (1).

Stem: Small and scale like. Radially symmetric, long creeping, short creeping or pendent, not readily fragmenting, irregularly forked, without budlike arrested branches, tips straight, main stem indeterminate, lateral branches determinate, spreading, 1-2 forked (1).

Leaves: Monomorphic, in alternate pseudowhorls of 4 (on main stem and older lateral branches), loosely appressed, ascending, green, linear to linear-lanceolate or narrowly triangular-lanceolate, (2-)2.5-3.4 x 0.45-0.5(-0.7) mm (1)

Inflorescence/flowers: Strobili sometimes paired, 0.5-3.5 cm, sporophylls lanceolate to ovate-lancelolate, abaxial ridges prominent, base glabrous, with prominent auricles. Margins entire or very short ciliate-denticulate, apex keeled, short to one-bristled (1). In easier language, the spores are produced within the axils of terminal leaves which often form a 4 angled spike (3).

Fruit: Heterosporous: two sizes of spores called megaspores and microspores

Similar species: Selaginella oregano

Ecology

Life history: perennial

Native/Introduced: native

Phenology: moist or shaded cliffs, rocky slopes, rock crevices, granite outcroppings, hanging over granite cliffs, sandstone or limestone ledges (1).

Distribution: AZ, CO, NM, TX, UT, WY, Mexico in Chihuahua and Nuevo Leon (1).

Uses

Human: Nothing is found for this particular species. Other Selaginella species are cultivated in greenhouses for their ornamental foliage. They are also planted in rock gardens in moist and shady places (2).

References:

1. Flora of North America North of Mexico, Volume 2. Edited by Flora of North America Editorial Committee. Oxford University Press, NY 1993.

2. Bailey, Liberty Hyde and Ethel Zoe. Revised and Expanded by Staff of the LHB Hortorium, Cornell University. Hortus Third. Macmillan Publishing Co, Inc. 1976.

3. Bailey, Liberty Hyde. The Standard Cyclopedia of Horticulture. Volume 3, P-Z. The Macmillan Company, NY. 1917.

Selaginella underwoodii Hieronymus By Elisabeth Alden, AZ Native Plant class, summer 2005 Common names: Spike moss, little club moss, Underwood’s spikemoss Family: Selaginellaceae Synonym: Selaginella fendleri (L. Underwood) Hieronymus 1900 not Baker 1883 (1) Etymology: Diminutive of Latin, Selago, an old name for a club moss (3). Identification Growth form: Plants are normally terrestrial, on rock. Roots: Rhizophores borne on upper side of stems, throughout stem length, 0.15-0.27(-0.3) mm diameter. Roots branching several times dichotomously from rhizophore tips (1). Stem: Small and scale like. Radially symmetric, long creeping, short creeping or pendent, not readily fragmenting, irregularly forked, without budlike arrested branches, tips straight, main stem indeterminate, lateral branches determinate, spreading, 1-2 forked (1). Leaves: Monomorphic, in alternate pseudowhorls of 4 (on main stem and older lateral branches), loosely appressed, ascending, green, linear to linear-lanceolate or narrowly triangular-lanceolate, (2-)2.5-3.4 x 0.45-0.5(-0.7) mm (1) Inflorescence/flowers: Strobili sometimes paired, 0.5-3.5 cm, sporophylls lanceolate to ovate-lancelolate, abaxial ridges prominent, base glabrous, with prominent auricles. Margins entire or very short ciliate-denticulate, apex keeled, short to one-bristled (1). In easier language, the spores are produced within the axils of terminal leaves which often form a 4 angled spike (3). Fruit: Heterosporous: two sizes of spores called megaspores and microspores Similar species: Selaginella oregano Ecology Life history: perennial Native/Introduced: native Phenology: moist or shaded cliffs, rocky slopes, rock crevices, granite outcroppings, hanging over granite cliffs, sandstone or limestone ledges (1). Distribution: AZ, CO, NM, TX, UT, WY, Mexico in Chihuahua and Nuevo Leon (1). Uses Human: Nothing is found for this particular species. Other Selaginella species are cultivated in greenhouses for their ornamental foliage. They are also planted in rock gardens in moist and shady places (2). References: 1. Flora of North America North of Mexico, Volume 2. Edited by Flora of North America Editorial Committee. Oxford University Press, NY 1993. 2. Bailey, Liberty Hyde and Ethel Zoe. Revised and Expanded by Staff of the LHB Hortorium, Cornell University. Hortus Third. Macmillan Publishing Co, Inc. 1976. 3. Bailey, Liberty Hyde. The Standard Cyclopedia of Horticulture. Volume 3, P-Z. The Macmillan Company, NY. 1917.