Diversity and Evolution of Monocots what where when how Monocots Old lineage lineage 134 mya Great diversity diversity habit habitat pollination morphology Adaptive radiations radiations orchids orchids 21 950 spp grasses grasses 10 035 spp Smallest largest seeds orchids Lodoicea maldivica Smallest fruit flower flowering plant Wolfia Wolfia We will finish our survey of angiosperms by examining the monocots a lineage of basal angiosperms Basal angiosperm lineage but is appearing to be closer to eudicots than most other basal angiosperms Tremendous economic importance Large group group 60 000 species Largest inflorescences titan arum palms bromeliads Monocots Diversity of aquatic habits Diversity in ecology Emergent Emergent floating floating or submerged aquatic group of monocots emergent Trees grasses rosettes vines epiphytes epiphytes Carnivores mycotrophs mycotrophs Habitats dry wet aquatic aquatic Pollination water wind zoophily These are the first diverging monocots submerged floating Monocot trees trees Monocot leaves No vascular cambium activity no true secondary growth wood Anomalous secondary growth trees trees Dragon tree a lily relative Woody palm Parallel venation or derived forms vs pinnate or reticulate venation as in most dicots more on this later Monocot flower common theme 3 merous Tepals are common Monocot Origins Monocots have usually been considered as derived out of basal angiosperms Ranales in the Bessey system or subclass Magnoliidae with Cronquist Diversity in pollination Striking modifications bracts grasses pulpits orchids spadices more Fossil record Crown group radiation 134 134 mya based on DNA evidence Pollen leaf possible early Aptian Early Early Cretaceous Cretaceous 113 125 mya Oldest unambiguously assigned fossil fossil Araceae Araceae 110 120 mya Cronquist Cronquist s view Cronquist Cronquist s view Classic idea of pre monocot characteristics 1 2 3 4 5 6 Herbs Aquatic Perianth not specialized Uni apperturate pollen Apocarpy Laminar placentation Nymphaeales Only non monocot order with all these characteristics monocot leaf morphology due to aquatic ancestry aquatic terrestrial aquatic pathways Cronquist Cronquist s view Monocot leaves phyllode theory Phyllode theory theory original monocot lacked a true leaf only expanded petiole celery left and tomato right asterid petioles showing parallel vascular traces monocot leaf is derived from an expanded bladeless petiole Phyllodes Phyllodes expanded blade less petioles best seen in arid adapted woody legumes such as Acacia Monocot leaves phyllode theory loss of blade expansion of tissue between parallel veins of petiole loss of blade expansion of tissue between parallel veins of petiole variable expansion of tissue between parallel veins in aquatic habitat Acorus sweet flag Monocot leaves phyllode theory variable divergence of parallel veins to leaf edge in aquatic habitat cross veins reticulated reticulated blades Net venation fleshy fruits functional ecological arguments for evolution of broad leaves and fleshy fruits of monocots in shady understory conditions T Givnish 1984 1999 2002 parallel pinnate parallel pinnate venation of palms and bananas Concerted convergence Occurrences of net venation are overlain on this phylogeny Concerted convergence Occurrences of net venation and fleshy fruits are overlain on this phylogeny Both features arise multiple times are correlated with each other arise in understory clades Acorales Acoraceae sweet flag Survey of monocots 4 main groups Acorales sister to all monocots Alismatids inc Aroids jack in the pulpit Lilioids lilies orchids yams non monophyletic petaloid Commelinids Arecales palms Commelinales spiderwort Zingiberales banana Poales pineapple grasses sedges Acoraceae sweetflag P6 Emergent aquatic plants with ethereal oils and no raphides 2 species Acorus calamus calamus Old World A americanus americanus New World Both species in Wisconsin Acorus sweet flag Flat filaments A6 G 3 seeds Inflorescence with spathe spathe and spadix Flowers bisexual Cellular endosperm dicot like Acorus americanus sweet flag Alismatales Alismatales aquatics 4 main groups Recurring themes Acorales sister to all monocots Alismatids inc Aroids jack in the pulpit Lilioids lilies orchids yams non monophyletic petaloid Commelinoids Arecales palms Commelinales spiderwort Zingiberales banana Poales pineapple grasses sedges Aquatic brackish marine habitats Insect water pollination Alismatales aquatics Alismatales aquatics Associated with the aquatic habit is the trend from insect pollinated showy flowers to water pollinated reduced flowers emergent Emergent floating or submerged aquatic group of monocots and increasing effort to vegetative rather than sexual reproduction submerged Showy flowers insect pollinated floating Reduced unisexual flowers waterpollinated Alismatales aquatics Araceae aroids 72 of Alismatales are unisexual monoecious or dioecious Sister family to other Alismatales 132 species are hydrophilous how many origins answer later epiphytes herbs aquatic Tropical to temperate Showy flowers insect pollinated Reduced unisexual flowers waterpollinated Araceae aroids 104 genera 2 550 species Araceae aroids Inflorescence a fleshy spadix spadix surrounded by bract called the spathe raphides in vacuoles with mucilage Ca oxalate endo osmosis CA 0 CO 0 A 6 G 2 3 Flowers unisexual or perfect Fruits berries clustered on spadix spadix defining characteristic is the inflorescence of spathe and spadix spathe or bract is common in monocots spathe cut away Symplocarpus foetidus skunk cabbage Arisaema triphyllum jack in the pulpit Araceae aroids Araceae aroids L female R male Cabbage like leaves emerge later in the spring Symplocarpus foetidus skunk cabbage Arisaema triphyllum jack in the pulpit or jill in the pulpit Araceae aroids Endogenous heating of skunk cabbage S S renifolius renifolius spadix sapromyophily pollination flesh flies Sarcophagidae Symplocarpus foetidus skunk cabbage carrion flies Calliphoridae Foetid smelling spathe and spadix emerges early in spring or late winter attracts carrion flies by heating up and volatizing off the odor gnats Mycetophilidae Onda Y et al Plant Physiol 2008 146 636 645 Cyclical heating of the skunk cabbage spadix in the male phase Araceae aroids Calla palustris water arum Only emergent aquatic member of the family in Great Lakes Araceae aroids Araceae aroids Zantedeschia arum lily funeral plants Monstera tropical aroid Spathiphyllum Araceae