Aquarium Frontiers On-Line: Aquatic Horticulture

AQUATIC HORTICULTURE

BY KAREN RANDALL

Do you have questions, want to discuss the issues raised in this column, or read the comments of other aquarists and the answers from columnist Karen Randall? You can do so by going to Aquatic Interactive.

It’s All in the Terminology

I thought it might be useful this month to go over a number of the terms we find in the literature about aquatic plants. If you have at least a nodding acquaintance with some of these terms, it will make it easier to understand some of the more technical texts available.

I have also included diagrams for a number of these terms. Please feel free to contact me via Aquarium Frontiers On-line if you run across other terms you would like to see explained.

Terms

Adventitious plant — plantlets that develop asexually from a parent plant

Alternate — single leaves placed alternately on either side of the stalk

Amphibious — able to exist either on land or in the water

Anaerobic — occurring in an environment that lacks oxygen

Angiosperm — a group of plants whose seeds are borne
within a matured ovary

Aquatic — growing in water

Asexual reproduction — any form of reproduction that does not require the union of male and female reproductive material

Axil — the junction of the leaf or petiole and the stem

KAREN RANDALL

Axillary — arising from the above junction

Bipinnate — leaf formed of several leaflets set on either side of the petiole

Bract — specialized scale-like leaf found at the base of a flower

Bullate — blistered, bubbled or puckered in appearance

Bulb — tightly packed fleshy leaves used as a storage organ. Onions and tulips both have bulbs

Chelators — synthetic organic acids that bind with various trace elements to keep them available in a form that is usable by the plants

Chlorophyll — the pigment that makes plants green. One of the pigments necessary for photosynthesis

Chlorosis — loss of chlorophyll, often a sign of insufficient amounts of iron

Compound leaf — a leaf that is divided into several distinct leaflets

Cordate— heart shaped

Cosmopolitan — found worldwide

Crenate — edged with rounded teeth

Crispate — with wave margins

Cultivar — a man-made (cultivated) variety

Cuticle — the thin skin of the plant. This is thicker and waxy to maintain moisture in emersed growth

Cutting — a fragment of plant material that is capable of growing to become another complete, individual plant

Decussate — opposite pairs of shoots set at right angles to the pairs above and below

Denticulate

serrated, edged with small teeth

Distichous — leaves arranged in two rows on either side of the stem

Division — a method of propagation in which the rhizome or vegetative cone is cut into pieces, each of which is capable of becoming a complete new plant

Emersed — grown above the water

Epiphytic — a plant that grows on another plant but is not parasitic

Endemic — a species found only in one specific location

Eutrophic — rich in dissolved nutrients, often caused by pollution

Filiform — thread like

Frond — the “leaf” of a fern

Hastate — with two out-turned lobes at the base

Herbivore — plant eater

Hybrid — the offspring of two parents of different species or varieties

Inflorence — flower cluster

Internode — the area between two nodes on a plant stem

Laminae — broad part of the leaf usually attached to the stalk by the petiole. Also called the blade

Lanceolate — spear shaped

Laterite — an iron-bearing red soil found in tropical or once-tropical areas of the world

Leaflet — one part of a compound leaf

Linear — long, narrow, grass-like or strap-like leaf

Monoculture — a large group of a single species of plant

Multipinnate — leaf divided into several sub-groups of leaflets

Neotropical — from the tropical areas of the new world (South or Central America)

Node — the point on a plant stem from which the leaves and/or roots appear

Offset — young plant growing along a stolon from the parent plant

Oligotrophic — deficient in nutrients needed for plant growth

Ovate — egg shaped

Paludal — from a marshy or swampy environment

Pectinate — comb like

Pedicel — the stem of an individual flower

Petiole — the “stalk” attaching the leaf to the stem

Photosynthesis — the conversion of light energy into chemical energy

Pinnate — divided

Plumiform — feather shaped

Polymorphous — having multiple shapes

Raceme — a group of flowers similar to a spike, but with each individual flower on its own stem

Reniform — kidney shaped

Rhizome — creeping stalk from which stalks and roots grow

Rosette — a plant that rises from a distinct crown

Sessile — a leaf that is directly attached to the plant stem with no petiole

Shaft — flower-bearing stalk

Spathe — modified leaf surrounding the flower

Spike — a group of flowers arranged closely at the end of a shaft, and attached directly to the shaft

Sporangium — the reproductive organ of primitive plants like ferns and mosses

Spore — the reproductive unit of primitive plants

Stolon — creeping offshoot or “runner” from which young plants arise

Submersed —growing underwater

Terrestrial — growing on land

Tuber — a swelling of root or underground stalk that functions as a storage organ as in a potato

Tissue culture — the production of new plants from small amounts of plant tissue under carefully controlled laboratory conditions

Vegetative cone — growing tip of the plant. On a stem plant, it is the tip of the stem. On a rosette plant, it arises from the very center of the rosette

Vegetative reproduction — reproduction via means other than sexual. Unless a mutation occurs, each generation of new plants is identical to the parent plant genetically

Whorl — a number of leaves evenly spaced around the stem

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AQUATIC HORTICULTURE