. A handbook of cryptogamic botany. Cryptogams. BA S IDIOM YCE TES 389 and forms on the surface a hymenium of club-shaped basids each of which produces four basidiospores. The spores divide at maturity trans- versely into four cells, only the two end cells of which germinate, doubt- less at the expense of the contents of the remaining two. The germ- tubes penetrate the epiderm of the leaf of the host, and a new mycele is formed which again bears basids. If, however, germination takes place elsewhere than on the proper host-plant, and conditions for the vegeta- tion of the fungus be otherwise f
. A handbook of cryptogamic botany. Cryptogams. BA S IDIOM YCE TES 389 and forms on the surface a hymenium of club-shaped basids each of which produces four basidiospores. The spores divide at maturity trans- versely into four cells, only the two end cells of which germinate, doubt- less at the expense of the contents of the remaining two. The germ- tubes penetrate the epiderm of the leaf of the host, and a new mycele is formed which again bears basids. If, however, germination takes place elsewhere than on the proper host-plant, and conditions for the vegeta- tion of the fungus be otherwise favour- able, the germ-tube begins to sprout in- definitely by means of elongated sprout- cells, giving rise to others only at the ends. This condition has been maintained in nu- trient solutions for a considerable time^ but the sprout-cells have never been observed actually to give rise to a new mycele like the one produced by the basidiospores. The Tremelline^ (Tremella, Dill., Exidia, Fr.) present another simple type. They are gelatinous fungi of not very definite form, commonly of wavy outline, and are saprophytic on old and dead wood. The hymenia are formed on the surface of the gelatinous mass. The basids vary in appearance, and are usually provided with fine elongated sterigmata and reniform spores. Certain forms such as Sebacina (Tul.) and Hypochnus (Fr.) do not possess gelatinous membranes. The course of development is much the same as in Exobasidium. The germinating basidiospore gives rise under ordinary con- ditions to the compound sporophore again. Under other conditions, it has been observed m Dacryomyces, the germ-tubes do not grow to any great length, but produce secondary spores, or they form sprout-cells. The basidiospores of the same form divide transversely at maturity, usually into four cells, each of which may germinate. It should be added that on germination these secondary spores give rise to myceles. The hyphae of such myceles, moreover, as well as those
Size: 1029px × 2428px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondonnewyorklongm
