629 
Cystidia of Coprinus atramentarius . 
Fig. 5. Horizontal section, taken in the direction c-d in Fig. 1, through the pileus flesh and 
four gills, p , the pileus flesh ; s, the edges of the gills towards the stipe; g, a gap indicating that 
the central parts of the gills have been left out for convenience of illustration ; c, the cystidia which 
prop the gills apart and thus maintain the interlamellar spaces. Magnified about 57. 
Fig. 6. Surface view of a piece of gill taken from the region r in Fig. 1. This drawing shows 
the distribution of the cystidia and basidia just before the beginning of spore-discharge and auto¬ 
digestion. e e, the oblique free inner edge of the gill bearing marginal cystidia m ; c c, cystidia pro¬ 
jecting from the gill ; 0 0, places where cystidia from the adjacent gill were in contact with the 
hymenial surface before the gills were torn apart. Between the cystidia are shown the basidia, each 
bearing four black spores. Magnified about 103. 
Fig. 7. Drawing showing the general appearance of part of a gill-surface, including the gill-edge, 
after spore-discharge and auto-digestion have begun (cf. Fig. 2). There are five zones running 
parallel to the oblique gill-edge: (1) a-a! , zone of basidia with ripe spores. (2) b-b', zone of 
basidia discharging spores into an interlamellar space. The spores are shot off their sterigmata 
successively, so that in this zone some basidia have three spores left upon them, some two, some one, 
whilst some have lost them all. (3) c-c', zone of basidia which have discharged all their spores. 
(4) d-d', zone of auto-digestion. The basidia and paraphyses are becoming indistinct and gradually 
liquefied. (5) e-e, the liquid film on the gill-edge containing the products of auto-digestion. 
/, position from which a cystidium has been removed by auto-digestion. Magnification 460. 
Fig. 8. Cross-section showing a cystidium stretching across an interlamellar space between two 
gills and thus separating two opposing hymenial surfaces. Magnification 440. 
Figs. 9, 10, and 11. Single cystidia, showing their variation in size and form and the nature of 
the subhymenial cells to which they are attached. Magnification 440. 
Fig. 11. A drawing showing the relative sizes and position of a cystidium, a basidium bearing 
four spores, some paraphyses, and some subhymenial cells. Magnification 440. 
PLATE LI. 
Figs, all of Coprinus atramentarius. 
Fig. 12. An optical section through a cystidium, showing the cell-wall, protoplasm, and 
vacuoles. Magnified 440. 
Fig s « 13-18 inclusive. The auto-digestion of six cystidia. a in each figure is a fully turgid 
cystidium just before the beginning of its auto-digestion, b, c, d , &c. show stages in the auto-diges¬ 
tion of each cystidium. The cystidia were observed stretching across interlamellar spaces near the 
auto-digesting edges of the gills. Figs. 13, 14, 15, and 17 show cystidia which became withdrawn 
to one of the gills. Figs. 16 and 18 show cystidia which, after becoming more and more slender, 
snapped into two parts; one part became withdrawn to one gill, and the other to the other gill. 
Fig. 15 shows the auto-digestion of a cystidium which had been separated whilst still turgid from one 
of the gills with which it was originally in contact with its rounded apical end. Fig. 17 shows the 
auto-digestion of a cystidium which had been separated whilst still turgid from the gill in which it 
had originated. Its free pointed basal end is shown at a. Magnification about 80. 
Fig. 19. Semi-diagrammatic section taken in a perpendicular plane through three gills during 
spore-discharge and auto-digestion (cf. Fig. 2). Seven zones can be distinguished: a , zone in which 
the cystidia are fully turgid and are propping the gills apart. The basidia bear spores which are 
nearly ripe, b, zone in which the cystidia are disappearing through auto-digestion. The spores are 
ready for discharge, c, zone of ripest spores from which the cystidia have already disappeared. 
d, zone of spore-discharge where cystidia are absent. Spores are being shot out into the interlamellar 
spaces. Their sporabolas are represented by arrows, e, the spore-free zone, f, zone of auto¬ 
digestion where basidia and paraphyses are being destroyed, g, the liquid film at the gill-edge 
containing the products of auto-digestion, h, the hymenial layer made up of basidia, paraphyses, 
and cystidia; s, the subhymenial cells; t, the trama. i i, cystidia which have been torn from the 
opposite gills by their rounded apical ends, j j, cystidia which have been tom from the opposite 
gills in which they originated so that they are now attached by their apical ends : their contracted 
bottle-neck-like basal ends are free, k k, cystidia which have become very slender owing to auto¬ 
digestion, but which are still attached to both gills. / /, cystidia which are being withdrawn to the 
gill-sides, m, a cystidium which has snapped into two parts. 0 0, remains of cystidia. Magnifica¬ 
tion about no. 
X X 
