Table 2. Observed Frequency of Degree of Spheres in the Silica Layer in Rice Husk Samples^a.

	degree of sphere
	1	2	3	4	5	6	7	mean degree	standard deviation
network 1	0	0	88	55	12	4	0	3.6	0.7
network 2	0	0	106	43	13	1	0	3.4	0.7
network 3	0	0	78	48	11	3	0	3.5	0.7
network 4	0	0	75	27	8	1	0	3.4	0.7
total	0	0	347	173	44	9	0	3.5	0.7

^aNetworks 1, 2, 3, and 4 correspond to the graphs in Figures 1e,f, S5k,l, respectively.