14 HARRY WARREN ANDERSON 



THE SIGNIFICANCE OF BUDDING 



The production of a new cell or a new individual plant by budding is an 

 entirely different process from the production of a new cell, conidium, or 

 spore by septation or abjunction. In the budding process a protuberance is 

 formed at some point on the parent cell. This swells and increases in size 

 in the distal portion but not' at the junction. This results in a narrow neck 

 which remains narrow during the further growth of the cell. When the 

 daughter cell has reached a certain size the protoplasm at the neck is separated 

 and a wall is formed between the end of this cell and the portion of the 

 original cell from which the bud arose. This results in 2 distinct and separate 

 individuals, and the daughter cell is very easily detached from the parent. 

 In the process of septation, on the other hand, the parent cell elongates and 

 the protoplasm is separated by a cross wall. If the fungus has a hyphal 

 development this usually takes place at the end of the hypha, that is, the growth 

 is apical. If a branch is formed a protuberance appears as in a bud, but there 

 is no constriction or only a slight constriction at the point of attachment to 

 the parent hypha. If budding is regarded as a type of reproduction com- 

 parable to the formation of conidia a difference may also be seen here in most 

 cases, in that usually the end of the sporophore elongates and the conidia are 

 cut off by septation as in the formation of a new cell. The cell which is cut 

 off to form the conidium may enlarge, become rounded, or change its shape in 

 various -ways. In some cases a condition falsely simulating budding seems 

 to occur, in that near the end of the elongated sporophore there appears a 

 sinus which gradually narrowing squeezes off the spore. But in this case the 

 conidium is from the first as broad as the parent hypha. In some of the lower 

 hyphomycetes there are conditions of conidial formation which closely approach 

 true budding. In these cases the resulting conidia when mature are definite 

 in form and size, and, on germination, produce true germ tubes. In the case 

 of the yeasts the buds are in no sense conidia or spores of the parent plant. 

 Rather they are new individuals ready to grow and carry on all the necessary 

 metabolic processes of the organism. On germination, conidia or spores send 

 out true germ tubes by the further growth of which a mycelium is formed. 

 In the budding process, on the other hand, the new cells formed, on further 

 growth, produce new buds and not germ tubes. 



It is recognized that the fungi which develop a true mycelium, such as 

 Exoascaceae and Ustilaginales may have budding stages in their life histories. 

 Budding is not rare in most of the larger orders of fungi, and may appear 

 under abnormal conditions in many forms (de Bary '87). It is not maintained, 

 on the other hand, that the yeast-like fungi described in this article never form 

 a septate mycelium. But it is asserted that there exists a group of fungi 

 which, under a very wide range of cultural conditions, rarely form septate 

 hyphae, but on the contrary produce new individual, unicellular plants almost 

 exclusively through the process of budding. 



GENERAL MORPHOLOGY 



Microscopic examination of all the cultures revealed a wide range of 

 morphologic characters. The only character all forms^ had in common was 

 that of budding. In young cultures, in all cases, the only form was the 

 budding yeast-like cells. These usually contained more or less distinct vacuoles, 

 although such were frequently absent. One or more refractive granules was 

 also evident in the vacuole or cytoplasm. In old cultures a decided change was 

 nsuallv evident in the structure and form of the cells. In many cases, the 



