Cyathea humilis is a species of tree fern

Cyatheales

The order Cyatheales is a taxonomic division of the fern subclass, Cyatheatae, which includes the tree ferns. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicates that the order is monophyletic. Some species in the Cyatheales have tree-like growth...

 native to Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

, as well as the Usambara

Usambara Mountains

The Usambara Mountains are a mountain range in North-East Tanzania, approximately long and ranging from 20 to in width. Mountains in the range rise as high as 8,000 ft ....

 and Uluguru Mountains

Uluguru Mountains

The Uluguru Mountains are a mountain range in eastern Tanzania, Africa, named after the Luguru tribe. The main Uluguru Mountains is a ridge running approximately north-south and rising to 2,630 m altitude at its highest point...

 in Tanzania

Tanzania

The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

, where it grows in wet forest at an altitude of 1100-2000 m. The trunk of this plant is erect and 2-3 m tall. Frond

Frond

The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...

s are pinnate

Pinnate

Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

 and 1-2 m in length. Dead fronds are often retained in the typical variety (C. h. var. humilis), forming an irregular skirt around the trunk. The rachis

Rachis

Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...

 and stipe

Stipe (botany)

In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....

 are light brown in colouration. Scale

Scale (zoology)

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

s are present towards the base of the stipe. They are dark, glossy, and have narrow, fragile edges. Sori

Sorus

A sorus is a cluster of sporangia .In fungi and lichens, the sorus is surrounded by an external layer. In some red algae it may take the form of a depression into the thallus....

 occur at the forks of veins and are protected by thin, reduced indusia.

Two distinct varieties

Variety (biology)

In botanical nomenclature, variety is a taxonomic rank below that of species: as such, it gets a three-part infraspecific name....

 of C. humilis are known. C. h. var. pycnophylla, the lesser known form, is endemic

Endemic (ecology)

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 to the Mogodoro district of Tanzania. This variety differs in the shape of its fronds and does not retain them as a skirt around its trunk. Further study is needed to more precisely determine the taxonomic

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 status of these plants.

Large and Braggins (2004) note that the holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 of C. humilis is "almost certainly a juvenile of Cyathea stuhlmannii", a taxon

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 also described by Hieronymus

Hieronymus

Hieronymus, pronounced , the Greek and Latin form of the name Jerome, means "sacred name."It may refer to several people:* Eusebius Sophronius Hieronymus, better known as Saint Jerome * Hiëronymus Emiliani, better known as St...

. Since the specific epithet

Epithet

An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

 humilis is older, it takes precedence, and C. stuhlmannii should be regarded as a junior synonym.