Ulvophyceae

Question 1

Answer 1

Ulva compressa (syn. Enteromorpha compressa)
Order: Ulvalves

thallus consisting of a hollow tube formed by cells arranged in a single layer

inside the tube there are bubbles of O2 produced by photosynthesis

the cells near the base produce rhizoids for adhesion to the substrate

Question 2

Answer 2

Ulva rigida: (sea lettuce)
Order: Ulvalves

similar to Ulva compressa but with bilayer laminar thallus. In culture it sometimes produces tubular thalli
its haplodiplontic reproductive cycle is representative of the majority of Ulvales

Question 3

Answer 3

Caulerpa prolifera
Order: Bryopsidales

Question 4

Answer 4

Caulerpa prolifera
Order: Bryopsidales

Question 5

Answer 5

Caulerpa taxifolia

Question 6

Answer 6

Caulerpa sertularioides

Question 7

Answer 7

Caulerpa racemosa

Question 8

Answer 8

Caulerpa mexicana

Question 9

Answer 9

Caulerpa paspaloides

Question 10

Answer 10

Codium sp.
Order: Bryopsidales

Thallus composed of a central body of siphonal organization filaments.
It consists of a compact mass of thin tubes that form a spongy thallus. It can take quite different forms, e.g. digitate, pulvinate or pillow, dicothomously branched

Question 11

Answer 11

Codium sp.

Thallus composed of a central body of siphonal organization filaments.
It consists of a compact mass of thin tubes that form a spongy thallus. It can take quite different forms, e.g. digitate, pulvinate or pillow, dicothomously branched

Question 12

Answer 12

Halimeda sp.
Order: Bryopsidales

It shows a thallus strongly encrusted with calcium carbonate to defend itself from herbivores

It is made up of flat calcified segments separated (blue arrow) by
non calcareous flexible joints (red arrow)

Question 13

Answer 13

Halimeda incrassata

It forms extensive meadows. This green calcareous alga grows about 6 meters deep and it represents a food source for turtles.

Question 14

Answer 14

Penicillus
Order: Bryopsidales

Thallus with multiaxial construction, consisting of dichotomously branched siphons aggregated at the base in a peduncle characterized by a large holdfast, but free at the apex giving to the alga a brush shape. The thallus is encrusted with calcium carbonate.

Question 15

Answer 15

Udotea cyathiformis
Order: Bryopsidales

Question 16

Answer 16

Ulothrix zonata
Order: Ulotrichales

Thallus consisting of filaments of uninuclear cells remaining united between them and characterized by plasmodesmata. Inside each cell, the ring-shaped parietal plastid with pyrenoids is visible.

Question 17

Answer 17

Cymopolia barbata
Order DASYCLADALES

Algae confined to shallow tropical and subtropical waters
Only 23 genera, there are many fossil genera

They are generally single-cell benthic algae that can reach several cm in length

The thalli have radial symmetry with verticillaster arrangement of lateral branches that arise from an erect central axis, anchored to the substrate by rhizoids

Question 18

Answer 18

Cymopolia barbata

very common alga in shallow water. This green alga reaches about 20 cm in lenght and has slightly calcified tufts at the ends of the branches, covered with calcium carbonate.

Question 19

Answer 19

Cymopolia sp.

Question 20

Answer 20

Acetabularia sp.

Small alga (5-10 cm), growing in groups in sheltered areas along the rocky coasts of the Mediterranean
It also grow in sandy substrates of lagoons attached to mollusc shells or stones
It shows the shape of a small umbrella, often whitish due to calcium carbonate encrustations