Calamite cone fossil A1.jpg

Calamostachys (Calamites cone) fossil

Upper Silesia Coal Basin GZW, Westphalian B - Rudzkie Bed
Pennsylvanian Age (~310 Million Years Ago)
Calamostachys represents the reproductive organ or cone of the Calamite tree. Calamites is a genus of extinct arborescent (tree-like) horsetails to which the modern horsetails (genus Equisetum) are closely related. Unlike their herbaceous modern cousins, these plants were medium-sized trees, growing to heights of more than 30 meters (100 feet). They were components of the understories of coal swamps of the Carboniferous Period (around 360 to 300 million years ago). The trunks of Calamites had a distinctive segmented, bamboo-like appearance and vertical ribbing. The branches, leaves and cones were all borne in whorls. The leaves were needle-shaped, with up to 25 per whorl. Their trunks produced secondary xylem, meaning they were made of wood. The vascular cambium of Calamites was unifacial, producing secondary xylem towards the stem center, but not secondary phloem. The stems of modern horsetails are typically hollow or contain numerous elongated air-filled sacs. Calamites was similar in that its trunk and stems were hollow, like wooden tubes. When these trunks buckled and broke, they could fill with sediment. This is the reason pith casts of the inside of Calamites stems are so common as fossils. Calamites reproduced by means of spores, which were produced in small sacs organized into cones. They are also known to have possessed massive underground rhizomes, which allowed for the production of clones of one tree. This is the only group of trees of their period known to have a clonal habit. This type of asexual reproduction would allow them to spread quickly into new territory, and help to anchor them firmly in the unstable ground along rivers and in newly deposited delta sediments. The rhizomes of Calamites look quite similar to the stems in most cases, but have nodes that get progressively closer together as they approach the apical area (the growth tip that spreads outward through the soil).
Kingdom: Plantae
Pylum: Tracheophyta
Class: Equisetopsida
Order: Equisetales
Family: †Calamitaceae
Genus: †Calamostachys