. The British rust fungi (Uredinales), their biology and classification. Uredineae. 14 GERMINATION OF TELEUTOSPORES Germination of the Teleutospore. We now approach the consideration of a process which has been in the past much discussed, and upon the right inter- pretation of which the whole question of the systematic position of the Uredinales depends. Each cell of the teleutospore of P. Caricis has one germ-pore, though some genera allied to Puccinia have teleutospores with more than one germ-pore to each cell, Phragmidium, Uropyxis, Calliospora. The germ- pore of the upper cell is in
. The British rust fungi (Uredinales), their biology and classification. Uredineae. 14 GERMINATION OF TELEUTOSPORES Germination of the Teleutospore. We now approach the consideration of a process which has been in the past much discussed, and upon the right inter- pretation of which the whole question of the systematic position of the Uredinales depends. Each cell of the teleutospore of P. Caricis has one germ-pore, though some genera allied to Puccinia have teleutospores with more than one germ-pore to each cell, Phragmidium, Uropyxis, Calliospora. The germ- pore of the upper cell is in the thickening at the summit, that of the lower cell is lateral and just beneath the septum. Each of these pores is a canal passing through the cell-wall, and covered only by the cuticle. Through these pores the germ-tube passes, first appearing as a roundish swelling, the protoplasm being surrounded by the thin endospore. This then elongates, the nucleus squeezes through the relatively narrow pore and enters the tube where it divides twice, and forms four superim- posed cells, separated by thin cell-walls (Fig. 16). This row of four cells was formerly known as a ijromyceluwi, but is now called a hasidium. If kept in water these cells can round off and separate from each other^, and germinate by sending out a tube, like the mycelial cells and spores of many fungi. But if in a damp^ atmosphere, each cell without separation produces a sterigma at the end of which a hasidiospore is formed, like the basidiospores of Agaricini. These basidiospores can germinate at once, even before they are detached from the sterigma, by sending out a short tube which may produce a conidiwm resembling the basidiospore at its Fig. 16. P. Caricis. a, a mature teleutospore; b, upper cell of same, germinating and forming a basidium; c, basidiospores germinating, x 600. 1 This method is said to take place normally in Barclayella. ' It is noted by many observers that, in a state of nature, it is a l
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