Oliver . — On the Obliteration of 
1 1 6 
EXPLANATION OF FIGURES IN 
PLATES VIII and IX. 
Illustrating Mr. F. W. Oliver’s paper on the Obliteration of the Sieve-tubes in 
Laminarieae. 
[N.B. — The figures are coloured in red to show the callus as stained with 
corallin-soda.] 
Fig. i. Macrocystis luxurians . A typical trumpet-hypha showing well-de- 
veloped callus-plate. (x 750.) 
Fig. 2. Macrocystis pyrif era. Large trumpet-hypha showing very well the mode 
of origin of the callus by an alteration of the cell-wall, (x 750.) 
Figs. 3, 4. Macrocystis pyrifera. Showing modes of branching of the trumpet- 
hyphae. In 4 the development of callus has proceeded some distance along 
the left-hand member. ( x 750.) 
Fig. 5. Nereocystis Liitkeana. Dilated portion of trumpet-hypha from an 
adult stem, showing very massive callus-development. ( x 700.) 
Fig. 6. Nereocystis Liitkeana. Showing a common form of branching met 
with amongst the trumpet-hyphae. ( x 750.) 
Fig. 7. Macrocystis zosteraefolia. Trumpet-hypha from a young stem showing 
the commencement of callus-formation. It will be noticed that the inmost 
layer of the wall is not coloured and as yet is not affected by the callus- 
transformation. The layer outside it — coloured a faint pink — is being altered 
into callus, (x 500.) 
Fig. 8. Nereocystis Liitkeana. This preparation is somewhat similar to that 
figured in 7. Several perforations are shown, as yet not quite blocked by 
the callus. One of these only reaches as far as the callus-layer, the other 
two quite to the middle lamella. ( x 500.) 
Fig. 9. Nereocystis Liitkeana. Preparation showing a local callus- formation 
some distance from the sieve-plate of the trumpet-hypha. The local callus- 
formation, l. c., is seen to be in the inmost but one stratum of the wall of the 
tube : the inmost layer may be seen bending round it. The lumen, /., of 
the tube is represented black. Owing to the callus-formation at /. c. it deviates 
considerably from its course. At c.p. is represented the ordinary callus-thickening 
of the trumpet-hypha. The sieve-plate is not represented. ( x 7 °°-) 
Fig. 10. Macrocystis luxurians. Showing a piece of a trumpet-hypha a 
considerable distance from any sieve-plate, in which the callus-formation is 
extending the whole length of the tube. At parts other than A and A 1 the 
whole wall has broken down into callus and the lumen is obliterated by the 
swelling up involved in this change. O'. 1. represents the remains of the 
lumen; at A callus-formation on the wall has not yet taken place, and at A 1 
the inner layers are not yet completely converted. ( x 800.) 
Fig. 11. Macrocystis planicaulis. Trumpet-hypha branching in close proximity 
to a sieve-plate. Callus-plates extremely well developed. ( x 750.) 
Fig. 12. Wide trumpet-hypha from an unnamed Laminaria from Vancouver’s 
Island with callus-plates. ( x 750.) 
