Q. No.1. Write down the habit and habitat of genus Lycopodium.

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Donald Lucas
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1 Frequently asked questions (FAQ S) Q. No.1. Write down the habit and habitat of genus Lycopodium. Ans. Plants are slender, herbaceous or shrubby sporophyte with a wide in habit and habitat. Stems of most species are much branched dichotomous branching and remains densely clothed with small leaves. are generally adventitious and formed along the entire length of the pro portion. The plants of Lycopodium are commonly known as creeping trailing pine, and club mosses. The genus is world-wide in distribu large majority of the species are found in tropics. In tropics are main pendulous epiphytes, and the temperate ones are prostrate trailing with upright branches and others are erect plants. It occurs in v climatic conditions; mostly the plants are moist and shade-loving. Q. No.2. Describe briefly the morphology of Lycopodium. Ans. The plants are rhizomatous herbs, stems are clothed with small sessile leaves of broad base and single unbranched vein. They range minute scales (L. densum) to broad leaves 2-3 cm long (L. phlegmario Leaves are mostly entire but in a few are serrate (L. serratum). In species the leaves are spirally arranged but some species show who decussate arrangement. The branching is fundamentally dichotomous. pseudomonopodial branching (unequal dichotomy) is manifested obscurum). Roots are adventitious occur on the under-side of the stem The genus has been classified into two subgenera. Members subgenus Rophalostachya are terrestrial species with prostrate creepin

2 and erect branches. The adventitious roots occur at the branchings. Th branching may be dichotomous but later branchings appear more mono (unequal dichotomy). SporophyIls are with dentate margins, are smalle foliage leaves and form strobilii which are simple or branched. S included in this subgenus do not form bulbils. In another sub Urostachya the plants do not have creeping axes but are erect (if terre or pendulous (if epiphytic) with dichotomous branching. The adven roots emerge at the basal region only. The sporophylls are alike to leaves and are restricted either to distal ends of the stems and branc are present alternate zones of fertile and sterile leaves all along the ste branches. Q. No.3. Differentiate between sporophylls from that of foliage Leaves. Ans. The sporophylls are alike to foliage leaves, but are restricted eit distal ends of the stems and branches or are present in alternate zo fertile and sterile leaves all along the stem and branches. In compari the entire margins of foliage leaves, sporophylls are with dentate m are smaller than foliage leaves and form strobilii. Q. No.4. Describe growth and branching in Lycopodium? Ans. In Lycopodium growth takes place by a group of cells, 'apical mer rather than a single apical cell as in stems of most pteridophyt dichotomous branching single centre of meristematic activity gives two. The initiation of two unequal centers is common in Lycopodiu results in pseudomonopodial branching. The most unequal branching in the formation of condensed axes which become specialized for veg propagation and are called "bulbils" or 'gammae". Some species (L. luc and L. sdago) regularly have typical unequal dichotomy and p

condensed branches (bulbils or gemmae) which on falling from the plant secure vegetative propagation. Q. No.5. What is the pattern of cortical layers in Lycopodium? Ans.

3 condensed branches (bulbils or gemmae) which on falling from the plant secure vegetative propagation. Q. No.5. What is the pattern of cortical layers in Lycopodium? Ans. The cortex in some species of Lycopodium remains parenchym (small stem) and in others with age the cortex gets sclerified into out inner zones, forming three bands, and in extreme cases the entire gets, sclerified. Large aerial stem normally has three-zoned c hypodermal chlorenchyma, followed by parenchyma, and scleren encircling the stele. In subterranean stem the cortex is often com sclerenchymatous. Aerial stems often have large air spaces in cortex disruption of cells. Endodermis is usually ill-defined and can be identi younger portions due to thickened radial walls (casparian strips). Q. No.6. Describe briefly the stellar anatomy of Lycopodium. Ans. Stellar anatomy differs from species to species and even within the species. However, young plants in all the species conform to a single pattern: a single rod of xylem

4 with radiating arms and phloem in between the xylem arms (Fig. 5a xylem and phloem are separated from each other by a layer of a parenchyma. Some species even retain this simple stellate arrangemen xylem of only four arms (Fig. a) (L. serratum, L. selago). In a deviatio this basic pattern irregular and increased furrowing of xylem takes pla in a cross section (Fig. b) it appears as isolated strands (L. lucidulum furrowing may result into plate-like lobes as in L. volubile (Fig. d). In forms the xylem retains its radiating arms pattern but also has patc xylem within main xylem, separated by parenchyma or strands of p (Fig. c) as in L. squarrosum. The stele is exarch. Wilder (1970) has, however, found the mesarch in L. clavatum, L. tristachyum and L. lucidulum. The protoxylem ele form a peripheral group of up to 20 cells with few or no inte parenchyma cells. This features separates Lycopodium from all other vascular plants. Q. No.7. Distinguish between protoxylem and metaxylem. Ans. Protoxylem` is the xylem derived from the apical growing poi elements are extensible and became partly thickened before elongatio can be stretched. Whereas metaxylem is derived from the procambium cells of metaxylem are heavily lignified and have reticulate thickeni pitted walls, in consequence they can not be stretched. Q. No.8. Describe the anatomy of embryonic root in Lycopodium. Ans. The embryonic root is short lived, the roots on older plan

adventitious and show equal dichotomous branching. Over the meristem of the root is the calyptra and proximal to the apex is a lon of unicellular hairy extensions borne in profusion.

5 adventitious and show equal dichotomous branching. Over the meristem of the root is the calyptra and proximal to the apex is a lon of unicellular hairy extensions borne in profusion. The cortex in roots complete tissue maturation is often completely sclerenchymatous. The is crescent-shaped (C or U) with phloem in concavity (Fig.6). The roo often diarch but usually they are not. The two protoxylem points a poles of U or C-shaped vascular strand but often one or more proto points are also located on the convex side of stele. The former mature than the latter. The roots originate chiefly from pericycle tissue of ste do not grow out straight through cortex but grow vertically (through th cortex) before emerging below. As a result in a transection of stem roots are seen in the cortex and are oriented in such a way that the ends of their xylem face towards the outside of stem. The roots of Lycopodium are peculiar in two respects; the lateral on

6 not endogenous in origin and root hairs are paired. In some specie stele is very similar to stem stele. Roots of L. clavatum have parallel pl xylem. At the point of attachment with the rhizome the root is polyar exarch. Therefore, except for size it becomes difficult to distinguish th organs. Q. No.9. Write down the different modes of vegetative reproduction in Ans. Vegetative reproduction in Lycopodium occurs by various ty propagules such as gemmae or bulbils; fragmentation; formation of buds and by the formation of root tubercles. The details are as: By the formation of gammae or bulbils These are modified vegetative structures that arise as lateral outg from near the stem apices and take the place of leaves. They have reported in L. selago, L. phlegmaria and L. lucidulum. Each bulbil cons a short and reduced axis surrounded by a number of thick and fleshy l These leaves store food material, they remain on the plant till root prem appear on the shortened stem. The gammae fall on the ground and gro a young plant. Fragmentation Death and decay of the older regions of the stem leading to the separa younger branches which grow into separate plants. This is the most co method of vegetative propagation in Lycopodium. Formation of resting buds

In L. inundatum, the tips on the apical buds of the rhizome and its bra store food material and become surrounded by densely crowded leave the resting buds.

7 In L. inundatum, the tips on the apical buds of the rhizome and its bra store food material and become surrounded by densely crowded leave the resting buds. In winter the whole plant accept these resting buds and at the advent of the favorable conditions the resting buds resume g and give rise to new plants. Formation of root tubercles In L. ramulosum, tubercles originate from the parenchymatous regions root cortex. They consist of a group of cells with stored food materi protected by thick walls and have the capacity to germinate into new pl Q. No.10. What are bulbils and how are they formed? Ans. Bulbils also called gamma are modified vegetative structures tha as lateral outgrowths from near the stem apices and take the place of l Each bulbil consists of a short and reduced axis surrounded by a num thick and fleshy leaves. The gammae or bulbils on separation fall o ground and grow into a young plant. Q. No.11. Draw a labeled diagram of Lycopodium strobilus. Ans.

Q. No.12. Describe the development of sporangia and spores in Lycopodium. Ans. The sporangia are borne on the adaxial surface of sporophylls but later may become axilliary in position.

8 Q. No.12. Describe the development of sporangia and spores in Lycopodium. Ans. The sporangia are borne on the adaxial surface of sporophylls but later may become axilliary in position. Each sporophyll produces only one sporangium. The sporangia are l-2.5mm in diameter, reniform to subspherical with short stalk or pad-like base. Sporangial initials differentiate normally on the upper side when sporophyll is still embryonic. Therefore longisection of developing cone all stages can be seen. By periclinal div the initials form inner and outer layers of cells (Fig. b,c,d). The inne

forms sporogenous cells and the outer layer forms the sporangial sta wall of the sporangium. This process in which sporangia develops f group of superficial cells is known as eusporangiate method.

9 forms sporogenous cells and the outer layer forms the sporangial sta wall of the sporangium. This process in which sporangia develops f group of superficial cells is known as eusporangiate method. After pe division due to differential growth i.e. active divisions in sporogenous result in upward bulging and the sporangium assumes a reniform Later, periclinal divisions in surface layer lead to the formation of five outer layer. The layer surrounding sporogenous cells stains deeply an as tapetum (Fig. f, g) and gets decomposed during maturation of spor the sporangia mature the peripheral layers also breakdown and a m sporangium has only one-cell-thick wall. Due to breakdown of periphe and tapetal layer spores come to l fluid mass. Q. No.13. Draw a labeled diagram mature prothallus of Lycopodiu show its internal structures. Ans.

10 Q. No.14. Describe sexual reproduction in Lycopodium. Ans. The sex organs in Lycopodium develop somewhat sunken surface of prothalli. These prothalli are monoecious and each sex originates from a single superficial cell just behind apical meriste subterranean types the antheridia and archegonia form distinct patch cover the entire crown or base of its lobe. Antheridia produce large num pear-shaped biflagellate antherozoid which are attracted chemotactica the archegonial exudate (citric acid). Archegonia are sunken at the and only the neck protrude. Subterranean prothalli have archegonia o

11 necks (as many as 14 neck canal cells in L. complanatum) and surface prothalli have short necked archegonia (sometimes just one neck canal L. cernum). At maturity, the neck cannal cells and ventre cana disorganize creating an open passage for the antherozoids to enter th and reach the egg. One of the antherozoids fuses with the egg forms or oospore. Q. No.15. How the embryo is developed in Locopodium? Ans. First division of fertilized egg is transverse to long a archegonium. The outer suspensor cell normally does not under go d or may become three-celled. The inner cell gives rise to two superim tiers of four cells each. The upper tier in some species swells up to foot and from the lower tier is derived the embryo proper. Accord Bruchmann (1910), two cells facing meristem develop into stem and two form leaves and primary root. Root differentiates laterally at a where apical region and foot are joined. In Some species (L. cernuum) tier develops into a massive globose structure-protocorm and pushes i through gametophyte. The protocorm bears rhizoids and from its surface differentiate leaf-like avascular structures, protophylls. Aft formation of many protophylls a shoot meristem is organized o protocorm. The first root arises from the base of stem. Protocorm, beca its structural organization apparently intermediate between gametophy sporophyte, has been looked upon by earlier workers as evolut forerunner of leafy vascular plant.

LYCOPODIUM Sub- Division- Lycopsida Order- Lycopodiales Family- Lycopodiaceae

LYCOPODIUM Sub- Division- Lycopsida Order- Lycopodiales Family- Lycopodiaceae LYCOPODIUM Distribution and Occurrence Commonly called: Club moss Ground pine Trailing over green Represented by 400 species,