Transitions and early land plants

• transition between vascular to non vascular

  liver worts lack stomata

  mosses have stomata but lack persistently green sporophytes

  hornworts lack independently branching sporophytes
• Obligate matroproph reliant on gametophytic nutrition
• Heterosporous - two types of spores produced, megaspores (female) and microspores (male)
• Homosporous - one type of spore produced
• Megaspore mother cell undergoes meiosis to produce four haploid cells, only the largest survives and develops into an embryo sac
• Embryo sac is surrounded by protective layers called integuments which eventually become seed coat