Trichopherophyton
Encyclopedia
Trichopherophyton is a genus of extinct vascular plant
s of the Early Devonian (Pragian, around ). Fossils were found in the Rhynie chert
, Scotland. The remains are very fragmentary, but the plant appears to be related to the zosterophylls.
, Rhynie, Scotland, which is of Early Devonian, specifically Pragian, age. The overall growth habit of the plant is difficult to construct. Some stems reached 2.5 mm in diameter, but their height is unknown; branching was possibly pseudomonopodial (i.e. one arm of a dichotomous branch continued as a 'main' stem). Uniquely among the Rhynie chert
plants, aerial stems bore rigid hairs or spines made up of single cells. Stems appear to have grown from coiled (circinnate) tips, in a manner similar to modern fern
s. Stems contained circular exarch xylem
strands with tracheid
s showing both annular and spiral thickening. The upright spore-forming organs or sporangia
were made up of two 'valves', the larger one facing away from the stem and bearing hairs, the smaller facing towards the stem and apparently not bearing hairs. The precise arrangement of the sporangia on the stems cannot be determined; there may have been zones of sporangia. Spores were released through a slit opening along the margins of the two valves of a sporangium. The trilete spores were about 55 µm in diameter.
Hairless stems bearing rhizoids but with a similar anatomy to the aerial stems are possibly the rhizomes of Trichopherophyton. Some actually grow through stems bearing hairs.
Vascular plant
Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...
s of the Early Devonian (Pragian, around ). Fossils were found in the Rhynie chert
Rhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
, Scotland. The remains are very fragmentary, but the plant appears to be related to the zosterophylls.
Description
Trichopherophyton was described from very fragmentary fossils found in the Rhynie chertRhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
, Rhynie, Scotland, which is of Early Devonian, specifically Pragian, age. The overall growth habit of the plant is difficult to construct. Some stems reached 2.5 mm in diameter, but their height is unknown; branching was possibly pseudomonopodial (i.e. one arm of a dichotomous branch continued as a 'main' stem). Uniquely among the Rhynie chert
Rhynie chert
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness . It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away...
plants, aerial stems bore rigid hairs or spines made up of single cells. Stems appear to have grown from coiled (circinnate) tips, in a manner similar to modern fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
s. Stems contained circular exarch xylem
Xylem
Xylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...
strands with tracheid
Tracheid
Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheids are one of two types of tracheary elements, vessel elements being the other. All tracheary elements develop a thick lignified cell wall, and at maturity the protoplast...
s showing both annular and spiral thickening. The upright spore-forming organs or sporangia
Sporangium
A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...
were made up of two 'valves', the larger one facing away from the stem and bearing hairs, the smaller facing towards the stem and apparently not bearing hairs. The precise arrangement of the sporangia on the stems cannot be determined; there may have been zones of sporangia. Spores were released through a slit opening along the margins of the two valves of a sporangium. The trilete spores were about 55 µm in diameter.
Hairless stems bearing rhizoids but with a similar anatomy to the aerial stems are possibly the rhizomes of Trichopherophyton. Some actually grow through stems bearing hairs.