F. T. Brooks . 
34-8 
Fig. 4. Eight nucleate embryo-sac. x 430. 
Fig. 5. Later stage ; the sac has begun to broaden near the base and starch 
has appeared in it. x 430. 
Fig. 6. Longitudinal section through an ovule at a stage later than Fig. 5, 
showing the growing embryo-sac. x 66. 
Fig. Ga. Embryo-sac of Fig. 6. x 430. 
Fig. 7. Mature embryo-sac, showing axial cone of nucellar cells projecting 
into the base ; much of the starch has disappeared, x 172. 
Fig. 7a. Polar nuclei of Fig. 7. x 860. 
Fig. 8. Base of another mature embryo sac, showing definitive nucleus, x 430. 
Fig. 9. Young embryo, x 280. 
Fig. 10. Later stage; the embryo-lies in a sap-containing cavity surrounded 
by endosperm x 280. 
Fig. 11. Longitudinal section through ovule at a later stage than Fig. 10, 
showing endosperm, and embryo with developing cotyledons, 
x 15. 
NOTES ON POLYPORUS SQUAMOSUS, HUDS. 
By F. T. Bkooks, M.A. 
(Demonstrator of Botany, University of Cambridge). 
[Text-Fig. 44.] 
T HE following notes were made last summer in regard to some 
sporophores of Polyporus squantosus which developed under 
conditions particularly favourable for observation. In regard to 
the liberation of spores, these remarks are confirmatory of Buller’s 
extensive world (reviewed in the present issue) on this portion of 
the general biology of certain groups of the Hymenomycetes. 
A cylindrical block of Acer Negiiudo about a foot in diameter had 
been brought into a room during the early part of May for the use 
of the Department of Forestry at Cambridge. On May 18th two 
groups of fungus fructifications which evidently belonged to Poly¬ 
porus squamosus were seen to be arising from the bark. When 
enquiries were made at the Botanic Gardens whence the block had 
come I learnt that the specimen had been cut from a tree which 
had been attacked in situ by this fungus. One group of fructi¬ 
fications consisted of a bulbous base from which three stalked 
sporophores of different sizes arose, the other comprised a similarly 
swollen base and a single rudimentary pileus. During the three 
weeks that the fructifications were kept under observation the 
1 Buller, A. H. R. “ Researches on Fungi,” Longman & Co., 
1909. 
