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Spore colour
48 eyes, nose and lips. Ozone is produced in substantial quantity by both a brand new and a dirty unit; precipitation efficiency also falls off very significantly if the filter is not cleaned frequently, particularly after use in dirty rooms. Our own experience suggests that once the precipitator has settled down after running for several days the production of ozone falls almost to nil and this acceptable level can be maintained if the filter is regularly and thoroughly cleaned. We have found that the filter should be cleaned with non-caustic detergent in warm water once a month, but the frequency of cleaning depends on the number of hours use. The much longer experience of Hopkins and his colleagues suggests that the carbon filter should be replaced annually. Roy Watling Royal Botanic Garden, Edinburgh
SPORE COLOUR Spore-print colour has long been used as a taxonomic character in identifying agarics. Thus although some families of the Agarica1es have members with a wide range of spore colour e. g. Boletaceae (yellow or pinkish to purple black though various browns), many families are defined in part on their spore print colour e. g. Coprinaceae black-spored, Bolbitia.ceae brown-spored. Even in these families individual species may be distinguished by the colour of their spore-print. Although these differences are small they can be seen by the careful observer, but they are difficult to define even with the aid of a set of colour standards. These differences in colour fade, often very rapidly and are mast obvious in fresh deposits, but it is difficult to get reproducible results even when spore-prints are examined immediately they are taken from below the fruit-body. Actively growing fruit-bodies usually give a much darker spore-print than an older, perhaps drier, fruit-body. In many cases this is simply due to the quantity of spores deposited, a thicker deposit giving a darker colour but there is some evidence to suggest that the water content of a deposit itselfmay differ from one collection to another, indeed the relative humidity of the atmosphere of the laboratory may effect the final colour recorded. Alexander H. Smith has hinted at a method of standardising the treatment of spore prints in order to get reproducible results; and we experimented throughout the summer and fall of 1966 at the University of Michigan Biological Station before finally deciding that fifteen minutes in a plastic container filled with activated silica gel gives reliable results which can be used for comparison. Agood spore-print can be obtained after one to twelve hours depending on the size of the fruit-body. Smaller speci:mens give results more quickly. The specimens should be enclosed in tins or boxes or greaseproof paper to prevent drying out; a drop of water placed on top of the smaller caps hinders excessive and rapid water loss. Once a sporeprint is obtained, preferably on a glass slide it should be dried as indicated above and scraped into a small pile. Place a cover-slip on the pile and exert gentle pressure, the eraser on the end of a pencil is ideal; compare spores with a colour chart.
49 It is interesting to note here that a change in shape of the basidio-
spores can alter the colour of the deposit considerably; a similar phenomena is experiences if the deposit is dried too rapidly in a hot air oven. Thus a deposit of Agrocybe praecox examined during a study of the Bolbitiaceae showed some areas typically snuff-brown and other, distinctly delimited areas, cigar-brown. In water or ammoniacal solutions no differences could be detected between spores from each of the sectors but when mounted in silicone oil those in the darker areas were collapsed and had obviously passed through the gut of an arthropod or insect for the contents appeared to have been completely sucked out. The differences in spore-print colour are the mass effect from several thousand basidiospores of the pigmentation of the spore wall, its complexity and thickness, and the type of ornamentation. It has been even more difficult to accurately define the colour of the individual spores because of the physical problems of comparing the colour of a spore under the microscope with a colour standard and the added disadvantage of having to observe the spores in artificial light ; some mycologists still prefer to carry out their observations on spores using daylight. It is possible to overcome some of the difficulties by using a camera lucida but these rarely give a bright enough image and only one or two spores can be observed at a given time. However the task is considerably eased by the use of the Willd M20 Binocular mic ro scope , By using the 8321 Drawing tube attachment groups of basidiospores in water or any reagent of ones choice (alkali solution, phloxine, cotton blue and Melzer's reagent), can be directly compared with a standard colour chart (of the observer's choice). The colour of the spore can be determined by directing the image of the spore on to a colour chart illuminated by a balanced light source which can be adjusted to coincide with the background colour about the spore. Thus small differences in spore colour between species of Suillus, Boletus, Leccinium, betwe en Conocybe blattaria and relatives, and the C. tenera complex, and between Psathyrella species can now be resolved, redefined and placed on a more scientific basis. Thus more meaning can now be placed on couplets such as :
(A) (A)
a
Spo r e e s remarquablement pales sous Ie microscope a lutac e a.Iutac S-pourp rf clair, presque comme etc. • ••••••••.•••••••.. Spo r ee ap.lu s fortement co lo r Se a sou s Ie microscope etc •••••.•••
(K\1hner and Romagnesi 1953, Flore Analytique des Champignons Supe r-i eu r a] etc. Roy Watling Royal Botanic Garden, Edinburgh
SPORE COLOUR Spore-print colour has long been used as a taxonomic character in identifying agarics. Thus although some families of the Agarica1es have members with a wide range of spore colour e. g. Boletaceae (yellow or pinkish to purple black though various browns), many families are defined in part on their spore print colour e. g. Coprinaceae black-spored, Bolbitia.ceae brown-spored. Even in these families individual species may be distinguished by the colour of their spore-print. Although these differences are small they can be seen by the careful observer, but they are difficult to define even with the aid of a set of colour standards. These differences in colour fade, often very rapidly and are mast obvious in fresh deposits, but it is difficult to get reproducible results even when spore-prints are examined immediately they are taken from below the fruit-body. Actively growing fruit-bodies usually give a much darker spore-print than an older, perhaps drier, fruit-body. In many cases this is simply due to the quantity of spores deposited, a thicker deposit giving a darker colour but there is some evidence to suggest that the water content of a deposit itselfmay differ from one collection to another, indeed the relative humidity of the atmosphere of the laboratory may effect the final colour recorded. Alexander H. Smith has hinted at a method of standardising the treatment of spore prints in order to get reproducible results; and we experimented throughout the summer and fall of 1966 at the University of Michigan Biological Station before finally deciding that fifteen minutes in a plastic container filled with activated silica gel gives reliable results which can be used for comparison. Agood spore-print can be obtained after one to twelve hours depending on the size of the fruit-body. Smaller speci:mens give results more quickly. The specimens should be enclosed in tins or boxes or greaseproof paper to prevent drying out; a drop of water placed on top of the smaller caps hinders excessive and rapid water loss. Once a sporeprint is obtained, preferably on a glass slide it should be dried as indicated above and scraped into a small pile. Place a cover-slip on the pile and exert gentle pressure, the eraser on the end of a pencil is ideal; compare spores with a colour chart.
49 It is interesting to note here that a change in shape of the basidio-
spores can alter the colour of the deposit considerably; a similar phenomena is experiences if the deposit is dried too rapidly in a hot air oven. Thus a deposit of Agrocybe praecox examined during a study of the Bolbitiaceae showed some areas typically snuff-brown and other, distinctly delimited areas, cigar-brown. In water or ammoniacal solutions no differences could be detected between spores from each of the sectors but when mounted in silicone oil those in the darker areas were collapsed and had obviously passed through the gut of an arthropod or insect for the contents appeared to have been completely sucked out. The differences in spore-print colour are the mass effect from several thousand basidiospores of the pigmentation of the spore wall, its complexity and thickness, and the type of ornamentation. It has been even more difficult to accurately define the colour of the individual spores because of the physical problems of comparing the colour of a spore under the microscope with a colour standard and the added disadvantage of having to observe the spores in artificial light ; some mycologists still prefer to carry out their observations on spores using daylight. It is possible to overcome some of the difficulties by using a camera lucida but these rarely give a bright enough image and only one or two spores can be observed at a given time. However the task is considerably eased by the use of the Willd M20 Binocular mic ro scope , By using the 8321 Drawing tube attachment groups of basidiospores in water or any reagent of ones choice (alkali solution, phloxine, cotton blue and Melzer's reagent), can be directly compared with a standard colour chart (of the observer's choice). The colour of the spore can be determined by directing the image of the spore on to a colour chart illuminated by a balanced light source which can be adjusted to coincide with the background colour about the spore. Thus small differences in spore colour between species of Suillus, Boletus, Leccinium, betwe en Conocybe blattaria and relatives, and the C. tenera complex, and between Psathyrella species can now be resolved, redefined and placed on a more scientific basis. Thus more meaning can now be placed on couplets such as :
(A) (A)
a
Spo r e e s remarquablement pales sous Ie microscope a lutac e a.Iutac S-pourp rf clair, presque comme etc. • ••••••••.•••••••.. Spo r ee ap.lu s fortement co lo r Se a sou s Ie microscope etc •••••.•••
(K\1hner and Romagnesi 1953, Flore Analytique des Champignons Supe r-i eu r a] etc. Roy Watling Royal Botanic Garden, Edinburgh