Monocots! Diversity and Evolution We will finish our survey of angiosperms by examining the of Monocots monocots - a lineage of basal angiosperms Basal angiosperm lineage, but is . what, where, when, how . appearing to be closer to eudicots than most other basal angiosperms Monocots! Tremendous economic • Large group: ~ 60,000 species! • Old lineage: ~134 mya importance • Great diversity: habit, habitat, pollination, morphology • Adaptive radiations: (orchids–21,950 spp; grasses–10,035 spp) • Smallest & largest seeds: orchids; Lodoicea maldivica • Largest inflorescences (titan arum, palms, bromeliads) • Smallest fruit, flower & flowering plant (Wolfia) 1 Diversity in ecology Diversity of aquatic habits emergent • “Trees”, grasses, rosettes, Emergent, floating, or submerged vines, epiphytes… aquatic group of monocots • Carnivores, mycotrophs… These are the first diverging • Habitats: dry, wet, monocots aquatic… • Pollination: water, wind, zoophily submerged floating Monocot “trees” Monocot leaves No vascular cambium activity Þ no true secondary growth (wood) • Parallel venation (or Anomalous secondary growth Þ “trees” derived forms) vs. pinnate or reticulate venation as in most dicots • (more on this later) Dragon tree – a lily relative Woody palm 2 Monocot flower: common theme Diversity in pollination 3-merous Striking modifications & bracts: Tepals are common grasses, pulpits, orchids, spadices & more! Monocot Origins Monocot Origins Monocots have usually been Crown group radiation: ~135+ mya [based on DNA evidence] considered as derived out of basal Pollen & leaf: possible early Aptian (Early Cretaceous), 113-125 mya angiosperms - Ranales in the Bessey system or subclass Magnoliidae Oldest unambiguously assigned fossil: Araceae, 110-120 mya with Cronquist 3 2018, Volume 105 • Givnish et al.—Monocot plastid phylogenomics • 9 0.18 PACMAD-BOP Puelioideae Pharoideae Anomochlooideae Monocot Origins Ecdeiocoleaceae Monocot leaf evolution Joinvilleaceae Flagellariaceae Restionaceae s.l. Xyridaceae Poales Eriocaulaceae 0.12 Mayacaceae Cyperaceae Juncaceae Thurniaceae Rapateaceae Typhaceae Bromeliaceae Zingiberaceae • cpDNA genome Costaceae Marantaceae 0.077 Cannaceae Heliconiaceae Zingiberales Strelitziaceae Lowiaceae phylogeny (Givnish et al. Musaceae Pontederiaceae Haemodoraceae Philydraceae Commelinales Commelinaceae Hanguanaceae 2018) 0.029 Arecaceae Arecales Dasypogonaceae Asparagaceae Dasypogonales Amaryllidoideae Allioideae Agapanthoideae Asphodeloideae Hemerocallidoideae Xanthorrhoeoideae Xeronemataceae Iridaceae Doryanthaceae • rapid radiation at base Ixioliriaceae Asparagales Tecophilaeaceae Lanariaceae Hypoxidaceae Asteliaceae Blandfordiaceae Boryaceae Epidendroideae Orchidoideae Cypripedioideae Vanilloideae Apostasioideae Liliaceae Philesiaceae Ripogonaceae • four large burst in species Smilacaceae Classic idea of pre-monocot characteristics – Cronquist’s view: Melanthiaceae Alstroemeriaceae Luzuriagaceae Liliales Colchicaceae Petermanniaceae diversification Campynemataceae Corsiaceae Pandanaceae Cyclanthaceae Tr iuridaceae Pandanales 1. Herbs Stemonaceae Velloziaceae Dioscoreaceae Thismiaceae Taccaceae Dioscoreales Burmanniaceae 2. Aquatic Nartheciaceae Petrosaviaceae Petrosaviales Hydrocharitaceae Nymphaeales Butomaceae Alismataceae Cymodoceaceae Ruppiaceae 3. Perianth not specialized Posidoniaceae Potamogetonaceae Only non-monocot Zosteraceae Maundiaceae Alismatales Juncaginaceae Scheuchzeriaceae 4. Uni-apperturate pollen Aponogetonaceae Tofieldiaceae order with all these other Araceae Lemnoideae Orontoideae Acoraceae Acorales 5. Apocarpy characteristics 140 120 100 80 60 40 20 0 Mya 6. Laminar placentation FIGURE 3. Monocot chronogram/diversigram. Ages of divergence of taxa at the subfamily, family, and ordinal levels of monocots and angiosperm outgroups are shown by branch depth. Signifcant accelerations of diversifcation are identifed by red dots; estimated rates of net species diversifca- tion (sp sp−1 My−1) from BAMM are color- coded as indicated. Area of bubbles is proportional to the number of species in terminal taxa. The Cretaceous- Tertiary boundary is indicated by the dashed line. See Appendix S13 for ages and 95% confdence intervals for all nodes within and among families. Monocot leaf evolution Monocot leaf evolution • monocot leaf morphology due to aquatic celery (left) and tomato (right) asterid petioles showing ancestry parallel vascular traces • monocot leaf is derived from • aquatic è terrestrial è aquatic pathways an expanded bladeless petiole 4 Monocot leaf evolution Monocot leaf evolution Phyllode theory: original monocot lacked a true leaf; only expanded loss of blade petiole variable & expansion expansion of of tissue tissue between between parallel veins parallel veins of petiole in aquatic habitat Phyllodes: expanded blade-less cross veins & petioles best seen in arid ‘reticulated’ adapted woody legumes such as blades Acacia Acorus sweet flag Monocot leaf evolution Monocot leaf evolution functional ecological arguments for evolution of broad leaves and fleshy fruits of monocots in shady understory conditions (T. Givnish, 1984, 1999, 2002) loss of blade variable & expansion divergence of tissue of parallel between veins to leaf parallel veins edge of petiole in aquatic habitat ‘parallel-pinnate’ venation of palms and bananas 5 Concerted Concerted convergence convergence Occurrences of net venation are Occurrences of net venation and overlain on this monocot fleshy fruits are overlain on this phylogeny monocot phylogeny Both features: • arise multiple times • are correlated with each other • arise in understory clades Survey of monocots Acorales (*Acoraceae - sweet flag) 4 main groups: • Emergent aquatic plants with ethereal oils and no raphides • Acorales - sister to all monocots 2 species: • Alismatales Acorus calamus, Old World – inc. Aroids - jack in the pulpit • “Lilioids” (lilies, orchids, yams): A. americanus, New World – non-monophyletic Both species in Wisconsin – petaloid • Commelinids – Arecales – palms – Commelinales – spiderwort – Zingiberales –banana – Poales – pineapple – grasses & sedges Acorus sweet flag 6 *Acoraceae - sweetflag Flat filaments *Acoraceae - sweetflag Flat filaments P 6 A6 G (3) ∞ seeds P 6 A6 G (3) ∞ seeds • Inflorescence with ‘spathe’ and spadix • Inflorescence with ‘spathe’ and spadix • Flowers bisexual • Flowers bisexual Acorus americanus - sweet flag Acorus americanus - sweet flag Alismatales Alismatales - aquatics 4 main groups: • Acorales - sister to all monocots Recurring themes: • Alismatales – inc. Aroids - jack in the pulpit Aquatic Þ brackish Þ marine habitats • “Lilioids” (lilies, orchids, yams) – non-monophyletic – petaloid Insect Þ water pollination • Commelinids – Arecales – palms – Commelinales – spiderwort – Zingiberales –banana – Poales – pineapple – grasses & sedges 7 Alismatales - aquatics Alismatales - aquatics emergent Associated with the aquatic habit is Emergent, floating, or the trend from insect-pollinated, submerged aquatic group showy flowers to water-pollinated, of monocots reduced flowers . and increasing effort to vegetative rather than sexual reproduction submerged Showy flowers, insect-pollinated Reduced unisexual flowers, water- floating pollinated Alismatales - aquatics *Araceae - aroids 72% of Alismatales are unisexual - • Sister family to other Alismatales monoecious or dioecious • Tropical (to temperate) 132 species are hydrophilous (how • epiphytes, herbs, aquatic many origins?) – answer later Showy flowers, insect-pollinated Reduced unisexual flowers, water- 104 genera pollinated 2,550 species 8 *Araceae - aroids *Araceae - aroids • raphides in vacuoles with mucilage Inflorescence a fleshy spadix, surrounded by bract called the • Ca-oxalate (endo-osmosis) spathe CA 0 CO 0 A 6- G (2-3) Flowers unisexual or perfect Fruits berries clustered on spadix spadix • defining characteristic is spathe the inflorescence of spathe (cut away) and spadix • spathe (or bract) is common in monocots 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 Foetid smelling spathe and spadix emerges early in spring or late winter; attracts Symplocarpus foetidus - skunk cabbage carrion flies by heating up Arisaema triphyllum - jack-in-the pulpit [or jill-in-the-pulpit ?] and volatizing off the odor 9 *Araceae - aroids Endogenous heating of skunk cabbage (S. renifolius) spadix sapromyophily pollination flesh flies – Sarcophagidae Symplocarpus foetidus - carrion flies – gnats - skunk cabbage Calliphoridae Mycetophilidae Onda Y. et.al. Plant Physiol. 2008:146:636-645 *Araceae - aroids *Araceae - aroids Calla palustris - water arum Only emergent aquatic member Monstera - tropical aroid of the family in Great Lakes 10 *Araceae - aroids *Araceae - aroids Zantedeschia other strange aroids: arum lily Amorphophallus - titan arum Pistia - water lettuce “Lemnaceae” - duckweeds funeral plants! Spathiphyllum *Araceae (Lemnaceae - duckweeds) *Araceae (Lemnaceae - duckweeds) Floating or submersed aquatic *family* almost cosmopolitan in distribution; Lemna Vegetative reproduction primarily Now known to be derived from within the Smallest member Araceae of the family and Lemna minor - small duckweed the angiosperms: Wolffia columbiana - Includes the smallest water meal angiosperm, and the smallest flower Spirodela polyrhiza Largest member of the family Inflorescence reduced to 1 great duckweed female and 1-2 male flowers Lemna turionifera