CHAPTER V.—COMPARATIVE REVIEW.—-USTILAGINEAE. 177 
episporium is almost or altogether colourless. The envelope-cells which adhere 
to the spores in Urocystis have likewise pale-coloured membranes at the time of 
maturity, and their contents are almost entirely watery. 
The germination of the resting-spores takes place when they are sufficiently 
supplied with moisture and have absorbed it to a sufficient degree. The form 
differs according as only water is supplied to the spores or nutrient matter also 
dissolved in the water, 
In the first case a short germ-tube is emitted, which takes the protoplasm of 
the spore and developes into a promycelium in the sense of section XXXI (p. 111). 
In most species the promycelium remains in connection with the membrane of the 
spore, in a few, as Ustilago Vaillantii, it soon separates from it. To this rule of 
development there are a few individual and specific exceptions which will be con- 
sidered presently. The further development is as follows :— 
1. Shoots are put forth acrogenously or laterally at the cost of the protoplasm 
and are abjointed; these in the terminology 
which has been proposed would be sporzdza 
(of the first order). The particular forms 
which their development assumes vary much 
in the several speciés; the chief ones, with 
which isolated intermediate or divergent kinds 
can easily be connected, are these :— 
a. A whorl or circle of narrowly cylin- 
drical or subulate sporidia (‘ Kranzkörper ’) 
shoots out from the obtuse and compara- 
tively broad apex of the promycelium. They 
appear simultaneously; their number in a 
whorl is different in different species and in- 
dividuals, varying between 4 and ıo. This 
mode is characteristic of most species of En- 
tyloma (Fig. 81), and for Tilletia (Fig. 83), 
Tuburcinia, and Urocystis. 
5. The promycelial tube is divided by ai pen ar ir ee 
transverse walls into a series of two or more en ee 
short cells, and from these are abjointed, nein. Kar Mg 
usually at their acroscopic extremity, a number 
of elongated or rod-like shoots as sporidia. This is the process in Tolyposporium 
Junci, Woronin, and in many species of Ustilago, for instance in U. Tragopogonis 
(Fig. 84 2), U. flosculorum, U. utriculosa, U. Cardui, U. Kühniana, and some others. 
c. The spore emits a simple, or in a very few cases a branched, short, slender 
promycelial tube, and from this is abjointed one cylindrico-fusiform sporidium 
or several in a row one after another (Ustilago longissima, Fig. 84 A, Thecaphora 
Lathyri according to Brefeld). 
2. The slender promycelial tube, which sometines puts out one or two branch- 
like protuberances, is divided by transverse walls into a few cells from which single 
sporidia are abjointed or sometimes none. This is the case with Ustilago Carbo 
(Fig. 84 C), U. destruens, and, according to Woronin, with Thecaphora hyalina. 
4, ° N 

