Glossary

Acropetal branching
Branches successively older (and longer) from top to lower part

Adaxial
Placed on the up-side of branch, towards the main axis

Adventitious branching
Branching occurring in an irregular manner, in addition to regular branching pattern

Apical
Most distant part

Biseriate
Two parallel cell rows

Caecostomata
Small cavity under the surface, characteristic for a group of Fucus

Calcified
Cells with calcified cell wall (calcite), giving a hard, opaque structure

Central cell
Axial cell row in some groups

Chloroplast
Cell organell containing the pigments (act. referring to green plastids)

Cortex
Cells covering axes, can be small and round or elongated cells

Cystocarp
Round or urn shaped female reproductive structure in some red algae

Dichotomously branched
Y branched (see illustration)

Dioecious
Male and female gametes produced in separate individuals

Distromatic
Two cell layers

Dorsiventrally flattened
Flattened and with two distinct surfaces

Epiphyte
Grows on other algae

Feather branching
Branching is regular in a consistent way, side branches forming an
“edge” like the one of a feather (see drawing)

Gamete
Sexual reproduction cell

Gland cells
Small cells without pigment

Hapteron
Root-like holdfast of seaweeds

Hermaphroditic
With male and female gametes in the same receptacle

Intercalary
Between cells, not in the apical part

Lamina
Blade-formed part of algae, normally referring to brown or red algae

Mid-rib
A conspicious thickened part of thallus which can be followed along the thallus, placed in the middle part

Monostromatic
One cell layer

Nerve
Polystromatic thickening of blade

Node
Joint in a segmented axis (e.g. cortex band in Ceramium)

Papilla
Nipple-like structure

Paraphyse
Small cell rows (or cell) protruding from surface, often associated with fertile structures in brown algae

Parenchyma
Solid tissue, where each cell do not follow a fixed division pattern but can in principle divide in 2 or 3 planes

Parietal
Located at the wall

Periaxial cells
Cells formed in a circle around the central (axial) cell

Plurilocular sporangium
Specialized branch or cell, divided in many rooms (loci), which each contain one spore

Pluriseriate
A cross section of thallus show more than one cell

Polystromatic
Several cell layers

Proliferation
Adventitious branching or outgrowths of new thallus part from an old one

Propagule
Vegetative reproduction unit, in Sphacelariales a specialized short
branch ending in two to four “horns” (short branches) set perpendicular
from the top of the branch

Pseudodichotomous
branches overtaking the growing top so that branching
appears to be more or less dichotomous

Pseudoparenchyma
Often (not always) loosely connected tissue, consisting of cell
rows where cell can only divide in one plane

Pyrenoid
Round structure associated to chloroplast

Receptacele
Specialized part of thallus which produces gamets in some brown
seaweeds (Fucales)

Rhizoid
Branch-like with little pigments and clearly different from
the other branches, can attach thallus to the substratum

Segment
Thallus axes divided in conspicious sections consisting of one or several cells of equal height (in Sphacelariales some of these can divide within the section). The sections can be covered with cortex cells (see illustrations p. 65)

Siphonous
Thallus lacks cell walls or has only some cell walls, thallus is composed of one or more large cells with many nuclei

Sorus (sori)
Aggregation of some type of reproduction structure

Stipe
Stalk-formed part of red or brown algae

Stipitate
With stipe

Stolon
Shoot growing sideways and attaching, and forming an upright thallus

Thallus
The “body” of a multicellular alga or fungus (equals “plant” in embryophyta)

Unilateral
On one side only

Unilocular sporangium
Specialized branch or cell, with one room (loci), which
contains many spores (asexual reproduction cells)

Uniseriate
Thallus composed of a cell row (may be branched or unbranched)

Veine
Cells forming a line pattern in the surface of the blade

Zoidangia
Specialized cells or structures producing flagellated reproductive cells