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Lyginopteris The amount of wood is relatively small in proportion to the total size of the stem. Systematic position: Five strands of mesarch primary Class: Pteridospermopsida xylem are present inside the secondary Order 1: Cycadofilicales wood. Family: Lyginopteridaceae Leaf traces are present outside the stele. Pith: The pith is large and parenchymatous Genus: Lyginopteris and possesses frequent clusters of small sclerotic cells forming sclerotic nests. Lyginopteris oldhamia (= Calymmatotheca hoeninghausii) is the most well-known plant Heterangium of the family Lyginopteridaceae. But as per —Heterangium is another stem genus rule of priority the correct name for associated with Sphenopteris leaf, reported Lyginopteris should be Calymmatotheca from Lower and Upper Carboniferous hoeninghausii, because it was described deposits of Scotland. earlier. —The stem is 2-4 cm in diameter which is The Lyginopteris plants were vine like, rarely branched. which grew with the support of neighbouring —The cortex is divided into two zones like trees or shrubs. All the parts of the plant Lyginopteris. (except roots) are provided with capitate —The primary vasculature is of mixed glands. The different common parts of the protostele. plants are as follows: —A narrow band of secondary xylem is present outside the primary xylem. Stem : Lyginopteris oldhamia —The secondary wood is similar to Fond: Sphenopteris hoeninghausii Lyginopteris. Root : Kaloxylon hookeri —The pith is large and reticulate. Rachis : Rachiopteris aspera Fronds: Pollen bearing Organ: i. Bipinnate or tripinnate leaves of Crossotheca hoeninghausii Sphenopteris hoeninghausii are about Seed : Lagenostoma lomaxi 0.5m long which are arranged spirally Cupule : Calymmatotheca hoeninghausii. on stem or branches. ii. Leaves are borne at right angles to Stems: the rachis which show alternately The stem of Lyginopteris oldhamia was arranged pinnules with free veins. frequently branched. It was long, slender iii. The leaf anatomy: and its diameter was 2 mm to 4 cm. cutinised upper epidermis, Anatomy of the stem: mesophyll tissue— divisible into Epidermis: A single epidermis, small palisade and spongy parenchyma. multicellular hairs are a common feature of iv. Leaf traces are formed by a the epidermis. tangential division of a primary xylem Cortex: broad cortex strand. The trace separates into a pair of The cortex is divided into two zones: strands in the cortex that fuse at the base outer cortex with radial patches of of the petiole- Rachiopteris aspera to sclerenchymatous cells resembling the form V-, Y- or W-shaped trace. Roman numerals on a clock face, and Petiole: Petiole is referred as Lyginorachis inner cortex which is parenchymatous. when it I preserved as isolated part with V- Stele and wood: Eustelic , Y- or W-shaped vascular bundle. A ring of secondary wood with radially Roots: Roots (Kaloxylon hookeri) are arranged multiseriate bordered-pitted adventitious, aerial and long. tracheids is present. ANC, Patna/Dept of Botany/B.Sc. II (Bot Hons)/Sushil 2 | P a g e

Anatomy- In T.S. epidermis with well vi. Nucellus is fused with integument except developed cortex is visible. at the apical chamber. A ring of 8 to 9 The cortex is divisible into two zones- vascular bundles travers the integument. Outer cortex- 2-3 layered parenchymatous Tip of the integument is divided in 9 outer cortex resembles velamen parts, each receiving a vascular strand. Inner cortex- broad parenchymatous, vii. The pollen chamber became more Secretory in nature complex by the formation of a flask- Endodermis and pericycle: occasionally shaped lagenostome due to the extended reported growth of nucellus. Vasculature: Pr. Vascular system is polyarch viii. Trilete pre-pollens are occasionally found showing radial arrangement. showing radial in pollen chamber. arrangement with Pollen-bearing organs: i.The male fructification Crossotheca hoeninghausii has been identified in association with the frond, Sphenopteris hoeninghausii. ii.The fertile part of Crossotheca is spathulate or hastate bearing a number of boat-shaped, pendent, bilocular microsporangia that lack an annulus. iii.The whole structure resembles minute hair- brush or epaulets. Other pollen-bearing organs of this family are Telangium, Telangiopsis and Feraxotheca. In these form-genera pollen organs are synangiate with many pollen sacs arranged pinnately. The pre-pollens are spherical with trilete aperture, measuring about 70 m in diameter. Seeds: i. A number of seeds or preovules namely, Lagenostoma, Physostoma, Sphaerostoma, Conostoma, Lyrasperma, Stamnostoma, Eurystoma, etc. have been identified. Lagenostoma lomaxi is better known. ii. Lagenostoma seeds are associated with ultimate part of Lyginopteris leaves which are about 5.5 mm. in length and 4.25 mm in diameter. iii. The seeds are covered with a protective covering called the cupule (Calymmatotheca hoeninghausii). iv. The cupules are provided with numerous capitate glands. v. The ovule is orthotropus, barrel-shaped and is covered by an integument which is divisible into outer stony and inner fleshy. ANC, Patna/Dept of Botany/B.Sc. II (Bot Hons)/Sushil