Morphology, anatomy and reproduction in Anthoceros

1. Morphological, anatomical and
reproductive characters of Anthoceros
Sankrita Gaonkar
Assistant Professor in Botany
sankrita002@gmail.com

2. Contents
• Morphology, anatomy and reproduction of Anthoceros
• References

3. Anthoceros
Classification:
• Class: Anthocerotopsida
• Order: Anthocerotales
• Family: Anthocerotaceae
• Genus: Anthoceros

4. Gametophyte
Morphology:
• Thallus is small, prostrate, dark green and dorsiventral
• Thallus – lobed
• Midrib absent
• Dorsal surface of thallus – in some – smooth, some velvet like or may spiny
• Rhizoids – smooth-walled
• Thalli are dark green – due to presence of Nostoc colonies

5. Anatomy:
• Upper and lower epidermis –
parenchymatous cells
• Air chambers and air pores are absent
• Each cell contains big chloroplast with
single pyrenoid
• Mucilage cavities – on ventral side –
small opening – slime pores
• Nostoc colonies can be present in
mucilage cavities
• No symbiotic relationship between
Nostoc and thalli
• Nucleus lie close to chloroplast, near
pyrenoid
• Sometimes chloroplast enfolds nucleus
within

6. Reproduction – vegetative and sexual
Vegetative reproduction:
• i) by progressive growth and death of thallus
• ii) by tubers – thallus become thicken at margins
• iii) by gemmae
• iv) by persistent growing apices – thalli become completely dried up in
summer, leaving growing apices – can tolerate drought

7. Sexual reproduction:
• Homothallic or heterothallic
• Antheridia (male) and archegonia
(female) – embedded in thallus
• Structure of antheridium
• Are produced in antheridial
chambers – no opening
• Mature antheridium – stalked and
oval
• Stalk – mass of cells or 4 rows od
cells
• Jacket layer – around antheridium
• Inside jacket are androcytes
• Antherozoid – spindle like and
biflagellate
• Dehiscence – after maturation, roof
of antheridial chamber breaks down

8. Archegonium
• Develop on flesh of thallus
• Archegonial location on thallus
identified by presence of mucilage
mound
• Jacket layer
• 4 – 6 neck canal cells
• Venter canal cell and egg
• 2 – 4 cover cells – get separated from
archegonium as soon as gelatinization
is over
• On maturation of archegonium – neck
canal and venter canal cells become
gelatinized. Thus, mature
archegonium is flask-shaped
• Fertilization

9. Sporophyte
• Consists of bulbous foot, meristematic zone and
slender, erect, cylindrical capsule
• Capsule – varies from 2-15 cm
• Foot – bulbous, multicellular, made of parenchymatous
cells. Absorb water and food from gametophyte
• Meristematic zone (intermediate or intercalary zone) –
base of capsule consisting of meristematic cells
(dividing cells) – makes capsule to grow for longer
periods – unique to Anthoceros
• Capsule
• Columella – central sterile portion, young – 4 vertical
rows, mature – 16 rows – provides mechanical
support, acts as water conduction tissue, and helps in
spore dispersal

10. • Archesporium (sporogenous layer) – between capsule wall and columella
• Upper part of capsule – it is differentiated into sporogenous tissue – produce
spores and pseudoelaters
• Capsule wall – consists of 4-6 layers of cells – outermost layer is epidermis –
cutin deposition – presence of stomata
• Inner layers of capsule wall contains chloroplast – self-sufficient to produce
food but partially depend on gametophyte for water and nutrients
• Dehiscence – basipetally – apex to base
• After maturation, capsule tip become brown or black
• Vertical slits appear in jacket layer

11. References
• https://sbancollege.org/study-
material/18652068835.Botany_RKSinha_29.07.2020.pd
• Pandey B.P. (2009). Botany for degree students: B.Sc. First
Year. S. Chand & Company Ltd. New Delhi.