Transcript Astrophytum myriostigma
Cactaceae
http://www.microscopy-uk.org.uk
Cactaceae Classification
APGII
30-200 genera, 1000-2000 species Basal Core Eudicots Caryophyllid clade
Characterized by
:
Spiny, succulent, photosynthetic stems Presence of betalins and P-plastids Flowers that have: many integrating tepals many stamens (hundreds) numerous stigma lobes (L.) Mill.
http://www.plantatlas.usf.edu
http://www.sdnhm.org/research/botany http://www.botany.wisc.edu
Cactaceae Classification
Caryophyllids http://www.ucmp.berkeley.edu
Placentation: Basal or Free Central Group also called “Centrospermae” or central seeds Seed: embryo curls around outer edge of seed, rather than laying in center Plastids in phloem cells: P-type plastids, rather than S-type plastids in other dicots Contain betalins: not found in any other plant
Evolution of Cactaceae
Recent studies of DNA variation and of vascular anatomy suggest that the closest angiosperm family is Portulaceae Cactaceae is a xerophytic lineage which arose from a common ancestor between Portuluceae and the “proto-cacti”
Speciated in the New World, most likely after the split of Gondwanaland
Originated either in Caribbean islands or NW South America http://www.cssnz.org
Subfamilies of Cactaceae
Perskioideae
Smallest subfamily; 18 species Predominately in South America Have differentiated into 4-5 geographically isolated groups within South America and the Caribbean Shrubby, tree-like, one species even forms vines Primitive Cactus Lack of succulence Presence of leaves Areoles with spines
Maihuenia
(Phil. ex F.A.C.Weber) K.Schum.
Most similar to the “proto-cacti” Many similarites with Portulaceae
Pereskia grandifolia
Haw.
Subfamilies of Cactaceae
Maihuenia tehuelches
Speg
.
Maihuenia patagonica
(Phil.) Britton & Rose http://www.astrokaktus.com
http://www.gargamel-cactus.com
Subfamilies of Cactaceae
Opuntioideae
About 300 species Occupies the most geographic range of the Subfamilies Coast to coast in North America (E →W), and central Canada to Patagonia Has invaded the Mediterranean, Africa and Australia 5 independent lineages (tribes) http://home-and-garden.webshots.com
(Haw.) Haw.
Maihueniopsis bonnieae
(D.J.Ferguson & R.Kiesling) E.F.Anderson.
http://www.plantatlas.usf.edu
Photos: Alicia Longo
Subfamilies of Cactaceae
Catoideae
Largest subfamily, about 86% of all species in Cactaceae family Over 1,000 species 8-10 independent lineages (tribes) within this subfamily 4 have thought to originated in North America, 5 in South America
Frailea pumila
Britton & Rose Tribe Notocacteae
Arrojadoa penicillata
Britton & Rose Tribe Cereeae http://www.answers.com
http://www.answers.com
Carnegiea gigantea
Britton & Rose Tribe Pachycereeae
Astrophytum myriostigma
Lem
.
Tribe Cacteae
Gymnocalycium mihanovichii
Pfeiff. ex Mittler Tribe Trichocereeae
Astrophytum myriostigma
Lem
.
Tribe Cacteae
Selenicereus wercklei
(A.Berger) Britton & Rose Tribe Hylocereeae Photos: http://www.answers.com
Structure and Function Modified Stems Fleshy, succulent stems
Species unspecified Some non-succulent, have 'fleshy' leaves instead (Pereskieae)
Photosynthetic Most lack woody tissue
A woody epidermal layer or stem present in some Enable cacti to live in hot, dry climates http://sliceoftheday.wordpress.com
Thick, fleshy stem: Reservoir to store water Waxy skin surface: Keeps water from evaporating Surfaces of most cacti can expand/contract to accommodate changes in the amount of water stored
Structure and Function
Modified Leaves Reduced to spines or absent
Few species have well developed leaves
Important benefits of spines:
Predatory defense (deters grazers) Provide shade Light colored spines reflect sunlight, preventing excess solar radiation http://www.microscopy-uk.org.uk
Structure and Function
Modified leaves, continued...
Develop from axillary buds, always located on areole
Central spines: grow at apex of areole Radial spines: grow around circumference of apex
Areoles grow in regular patterns on the stem
Alternate Deciduous (when well developed leaves present) Species unspecified http://www.microscopy-uk.org.uk
http://www.cactus-chile.cl
Structure and Function
Spineless Cacti
Produce toxic substances to deter grazers
Lophophora williamsii
(Lem.) J. Coult., or “Peyote” Produces mescaline, a hallucinogenic narcotic Illegal in United States Used legally by one, unspecified, Native American group http://www.mescaline.com
http://www.answers.com
Structure and Function
Various species
Root System Fibrous, branching roots
Shallow and long Exploit water deposited at surface by short periods of rain Some have shorter, compact roots that absorb dew water falling off of downward directed spines
Taproot
Reaches deeper layers of soil Helps anchor the plant, as well as obtaining deeper lying water and nutrients http://www.cactusmuseum.com
Notocactus arechavaletai
(Speg.) Hert.
Structure and Function
Echinocereus fasciculatus
(Engelm. ex B. D. Jacks.) L. D. Benson
Flowers
Present in all cacti Many are short-lived (days); Some only open at night Short blooming periods lessen amount of water that may evaporate through petals Solitary or inflorescences Can be fragrant or odorless Actinomorphic Perianth free or joined basally Stamens: numerous Carpels: 3-numerous Ovary: inferior, embedded in tip of stem Placentation: parietal http://www.botany.hawaii.edu
Rathbunia alamosensis (J. Coulter) Britton & Rose
Lygaeus equestris
(L.)
Sulcorebutia gerosenilis
Riha & Arandia http://gis.esri.com
http://www.cactus-art.biz
Echinocereus reichenbachii
(Terscheck ex Walpers) F.Haage
http://www.atmstravelnews.com
Pachycereus
(A.Berger) Britton & Rose
Opuntia cochenillifera
(L.) Mill.
Structure and Function
Water Storage/Transport Stoma
Open at night to conserve water
Stem
A reservoir; can expand/contract depending on amount of water to store Cortex mainly parenchyma Cortical bundles and secondary phloem/xylem
Roots
Shallow to absorb surface water during rain Break off during extended periods of drought No water loss to soil
Astrophytum myriostigma
Lem.
Cereus repandus Haw.
http://www.sbs.utexas.edu
Edible Fruit
Economical Importance
http://www.tomzap.com
Berries
Opuntia
(L.) Mill. (prickly pear, India fig, tuna, etc)
Stenocereus
(A.Berger) Riccob.
S. gummosus
'most tasty'
Cereus
Haw.
•
Ferocactus
Britton & Rose and
Echinocactus
Link & Otto (barrel cacti) Medical Uses Stem extracts can be used as anti diabetic agents, diuretic, laxative, and treatment for stomach ulcers, burns, and kidney disease Florist Trade/Landscaping Multi-million dollar plant business anually Many taken from the wild http://www.sfgate.com
http://upload.wikimedia.org
Endangered/Threatened Species
Astrophytum asterias
Lem.
Sclerocactus brevispinus
K. D. Heil & J. M. Porter
Pilosocereus polygonus
(Lam.) Byles & G.D
http://www.nativeecosystems.org
http://cactiguide.com
Echinocactus horizonthalonius
Lem.
Pediocactus peeblesianus
(Croizat) L. D. Benson http://www.tosca.si
http://www.botanica.uk.net
http://www.centerforplantconservation.org
Florida Species
(Haw.)Britton & Rose (Haw.)Kimnach Photos: http://www.plantatlas.usf.edu
Florida Species
(Raf.)Raf. (Raf.)Raf. Photos: http://www.plantatlas.usf.edu
(J.S.Mill.)Stearn
Photos: http://www.plantatlas.usf.edu
Haw.
Florida Species
(L.)Britton & Rose
References
Binns, Corey. “How Cacti Survive: Surprising Strategies Quench Thirst.” 24 July 2006. 24 August 2008.
” 14th February 2008.24 February 2008.