Welcome to an overview of what Economic Botany has to offer.
It will be a distance learning course this spring 2000, so below are highlights of what I plan
to be doing in the TopClass format
LECTURE 7 HHIGHLIGHTS FOR BIO 03074, ECONOMIC BOTANY: WEEDS AND ALIEN INVADERS
Text: 2nd ed.: Ch. 6 (p. 96), Ch. 22 (pp. 392-393); 1st ed.: Ch. 6 (p. 93), Ch. 21 (aspects), Ch. 22 (pp. 357-361)
possible web site: http://aquat1.ifas.ufl.edu/hyacin.html (efforts to control the water hyacinth)
weed:"a plant considered undesirable, unattractive, or troublesome, esp. one growing where it is not wanted, as in a garden." ref: Webster's II New Riverside University Dictionary
PLANTAIN: PLANTAGO SPP.
Plantaginaceae, the plantain family: Flowers in spikes. Seeds mucilaginous when wet. Herbs with basal leaves.
Plantago, plantain or rib grass is a very common lawn weed, naturalized from Europe. The seeds of P. psyllium are used to make laxatives (seeds bulk, the mucilage as lubricant)--Metamucil.
WATER HYACINTH: EICHHORNIA CRASSIPES
Pontederiaceae, the pickerel-weed family: Perennial warm climate freshwater herbs, attached or floating. Pontederia, pickerel weed; Eichhornia, water hyacinth.
The water hyacinth is native to South and Central America. Plants float and are loosely attached to each other by stolons. The plant typically reproduces by clonal propagation. The water hyacinth first drew attention in the US at the 1884 International Cotton Exhibition in New Orleans. The Japanese delegation handed out samples of the plant. Within 10 years, a plant that can double its numbers in 2 weeks had gone haywire throughout the US Southeast and Southeast Asia. Florida's nutrient-rich waterways are notoriously affected, not only for boat traffic but also for irrigation. Mechanical harvesters and herbicides haven't worked to keep this weed under acceptable control.
KUDZU: PUERARIA LOBATA
Kudzu, a member of the Fabaceae, was first seen in 1876 at the Japanese pavilion at the Philadelphia Centennial Exposition. Imported massively from Japan in 1930s to help control soil erosion. But, without natural enemies, kudzu grows up to 1 foot/day. Given this growing capacity, kudzu covers everything as it grows along
CHESTNUT BLIGHT
Fagaceae, the beech family: Catkin-bearing trees and shrubs with pinnately lobed leaves, buds clustered at twig tips, and fruits (nuts) at least partially enclosed by a cupule (fused bracts). 8 genera, 900 species. Fagus, beech; Quercus, oak; Castanea, chestnut.
Castanea dentata is the American chestnut that has been devasted by the fungus Cryphonectria parasitica (Endothia parasitica), the chestnut blight. The chestnut tree used to be a major species in the Eastern US forest, valued for its high-tannin wood. The fungus was accidently introduced from Asian chestnut trees to NYC in 1890s. It killed about 80% of Eastern US chestnut trees by 1950s, greatly altering forest ecology.
DUTCH ELM DISEASE
Ulmaceae, the elm family: Fruit a samara, with wing equal on all sides (unlike a maple). Trees and shrubs with simple, alternate leaves that have unequal leaf bases. Ulmus, elm.
Ulmus americana has been an important shade tree (think of all the Elm Streets). Dutch elm disease is caused by the vascular wilt fungus Ophiostoma ulmi, which was accidently imported on infected elm timber used for veneers in 1930. Upwards of 40 million urban elms have died in the US.
PURPLE LOOSESTRIFE: LYTHRUM SALICARIA
Lythraceae, the loosestrife family: Herbs and trees with often crumpled petals. Lythrum, loosestrife; Lagerstroemia, crepe myrtle.
Purple loosestrife is a pretty perennial with underground rootstocks and prodigious seed production that sends stems up several feet high along wetlands. It is an aggressive invader that crowds out native species.
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|03050: Invertebrate Zoology| |03051: Vertebrate Zoology| |03074: Economic Botany|
Please send comments and questions to: cronewil@hvcc.edu
Copyright 1999 by Wilson Crone
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This page updated on October 4, 1999