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Updated: June 16, 2025
Those first produced have numerous papillæ on them, and were called Uredospores, from their analogies with the uredospore of the rust of wheat; the second kind of spore is smooth, and is called the Teleutospore, also from analogies with the spores produced in the late summer by the wheat rust.
Their appearance can be called to mind by imagining the cylindrical fruit of the maize or Indian corn to be reduced to some three or four inches in length. The sporangia or cases which contained the microscopic spores or seeds were arranged around a central axis in a somewhat similar manner to that in which maize is found.
Spherical spores with thick covering of granulated surface. Spherical spores with punctulated surface 0.007 millimeter in diameter. Very minute, transparent, bluish-greenish colored spores, with thin covering and finely granulated contents 0.006 millimeter in diameter. Chroococcoid cells with two larger nuclei 0.0031 millimeter in diameter.
C, there is little or no doubt; but that there are some which are much more tenacious of life, that is, possess greater vital resistance to heat, is equally unquestionable. M. Pasteur, for instance, mentions the spores of certain fungi which are capable of germinating after an exposure of some minutes to a temperature of 120A deg. to 125A deg. Dr.
Since old soil is often full of fungous spores left by previous crops, it is the wisest plan to use sterilized soil for the seed-bed. When the young plants are growing, constant watchfulness is required to avoid conditions that will weaken the seedlings and favor the damping off fungi. Watering and ventilation are the two points that require especial skill.
When shaken over a glass plate these spores cause a point of light, looked at through the dusted plate, to be surrounded by coloured circles, which rise to actual splendour when the light becomes intense. Shaken in the air the spores produce the same effect.
These spores germinated and grew, until finally their stems were petrified by carbonate of lime like some of the remaining portions of the wood of the containing Sigillaria. Mr. Carruthers has discovered that sometimes the plants which had thus grown and become fossil in the inside of a single trunk belonged to several distinct genera.
And, although ancient club-mosses have been found in a fossilised condition at least forty-nine feet high, the spores are no larger than those of our miniature club-mosses of the present day. The spores are more or less composed of pure bitumen, and the bituminous nature of the coal depends largely on the presence or absence of these microscopic bodies in it.
In structure, however, the Peronospora is as much a mould as the common Penicillium; and just as the Penicillium multiplies by the breaking up of its hyphoe into separate rounded bodies, the spores; so, in the Peronospora, certain of the hyphoe grow out into the air through the interstices of the superficial cells of the potato plant, and develop spores.
One striking feature in connection with the fruit of the lepidodendron and other ancient representatives of the club-moss tribe, is that the bituminous coals in many, if not in most, instances, are made up almost entirely of their spores and spore-cases.
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