An alga infested with a Chytridiumindeed, matters can hardly be otherwise.
One in which the alga and fungus are equally distributed.
Granatina the primary alga is Pleurococcus, the secondary, Gleococapsa.
Gomontia is a shell-boring alga, A.
The genus Dictyonema has gonidia belonging to the bluegreen alga, Scytonema.
Botrydium, a simple siphonaceous alga with root-like attachment.
It certainly supports his view to discover, on subjecting to a careful investigation Botrydium granulatum, a siphonaceous alga whose varied forms had been described by J.
A genus Zonatrichites, compared with species of Cyanophyceae, has been described as a Calcareous alga from Liassic limestones of Silesia.
Brown or even blood-red stripes have been observed in the North Atlantic when swarms of the copepod Calanus finmarchicus were present; the brown alga Trichodesmium erythraeum, as its name suggests, can change the blue of the tropical seas to red; swarms of diatoms may produce olive-green patches in the ocean, while some other forms of minute life have at times been observed to give the colour of milk to large stretches of the ocean surface.
Species of alga) but a few forms are known (Lecanora granatina, Solorina crocea) which make use of more than one kind in their development.
The more important part in lichen distribution as the development of the r1012444 ordinary spores is dependent on their ?,O.° finding the proper alga on the sub- I t.?
This dualism, where the one constituent (alga) furnishes carbohydrates, and the other (fungus) ensures a supply of mineral matters, shade and moisture, has been termed symbiosis.
Second alga described previously by Kiitzing, and now described afresh by Klebs as Protosiphon botryoides.
He investigated the exact relation of fungus and alga and showed that the same alga is able to combine with a number of different fungi to form lichens; thus Chroolepns umbrinus is found as the gonidia of 13 different lichen genera.
Extremity of a branch of the thallus with a young lateral branch a; h, hyphae; g, cells of the alga; gs, the apex of the thallus.
On a bare rocky surface a fungus would die from want of organic substance and an alga from drought and want of mineral substances.
Alga-like fungi with unicellular thallus and well-marked sexual organs.
While the spore of Bryophyta on germination gives rise to the sexual plant, the carpospore of the alga may give rise on germination to a plant bearing a second sort of asexual cells, viz.
In the case of Scenedesmus acutus it is said that the alga is unable to take up nitrogen in the form of a nitrate or ammoniacal salt, and requires some such substance as an amide or a peptone.
It is believed, however, that the Devonian fossil, Nematophycus, is a Laminarian alga, but it is not until the late Secondary and the Tertiary formations that fossil remains of algae become frequent.
Lorenzo (1380-1465), the Laurentius Justinianus of the Roman calendar, at an early age entered the congregation of the canons of St George in Alga, and in 1433 became general of that order.
There appears to be no reason to doubt that the sexual generation is homologous with the thallus of a Liverwort, or of such an Alga as Coleochaete.
It consists of minute interwoven tubular filaments, and has been variously interpreted as possibly representing the sheaths of a Cyanophycean Alga, and as constituting a Siphoneous thallus of the type of the Codieae.
A branched filamentous organism from the Lower Carboniferous of Scotland, described by Kidston under the name of Bythotrephis worstoniensis, shows some remains of cellular structure, and may probably be a true Alga, resembling some of the filamentous Florideae in habit.
A, Cell (individual) of the unicellular Green Alga Pleurococcus, as an example of an undifferentiated autonomous assimilating cell.
B, Plant of the primitive Siphoneous Green Alga Protosiphon botryoides.
C, Base of the multicellular filamentous Green Alga Chaetomorpha aes-ea.
D, Part of branched filamentous thallus of the multicellular Green Alga Oedocladium.
E, Vertical section of frond of the complicated Siphoneous Green Alga Halimeda.
F, Section through the surface tissue of the Brown Alga Cutleria multifida, showing the surface layer of assimilating cells densely packed with phaeoplasts.
G, Section showing thick-walled cells of the cortex in a Brown Alga (seaweed).
The relations of the Alga and the Fungus, which have formed a close associationship in the structure known as the Lichen, were established many years ago.
The alga by its own peculiar movement will soon form a radiating circle, perfectly free from dirt, around the coin, which may then be removed.
Filamentous diatoms may be mounted like ordinary seaweeds, and, as well as all parasitic algae, should whenever possible be allowed to remain attached to a portion of the alga on which they grow, some species being almost always found found parasitical on particular plants.
Owing to their peculiar dual nature, lichens are able to live in situations where neither the alga nor fungus could exist alone.
The enclosed alga is protected by the threads (hyphae) of the fungus, and supplied with water and salts and, possibly, organic nitrogenous substances; in its turn the alga by means of its green or blue-green colouring matter and the sun's energy manufactures carbohydrates which are used in part by the fungus.
In the case of Solorina, for example, the principal alga is a green alga, one of the Palmellaceae, but Nostoc (a blue-green alga) is also found playing a subsidiary part as FIG.
When the alga is predominant it forms felted patches on the bark of trees, the Laudatea form.
The Latin word alga seems to have been the equivalent of the English word " seaweed " and probably stood for any or all of the species of plants which form the C/assifl- " wrack " of a seashore.
Certain markings on slates and sandstones, such as the "fucoids" of Scandinavia and Scotland, the Phycoides of the Fichtelgebirge, Eophyton and other seaweed-like impressions, may indeed be the casts of fucoid plants; but it is by no means sure that many of them are not mere inorganic imitative markings or the tracks or casts of worms. Oldhamia, a delicate branching body, abundant in the Cambrian of the south-east of Ireland, is probably a calcareous alga, but its precise nature has not been satisfactorily determined.