Table 2.

Comparison between the energetics of spore discharge in basidiomycete species with the largest (Aleurodiscus gigasporus) and smallest ballistospores (Hyphodontia latitans).

Species	Aleurodiscus gigasporus	Hyphodontia latitans
Available surface tension energy1	2.9 × 10−11 J	2.6 × 10−14 J
Energy to break connection2	1.6 × 10−14 J	1.6 × 10−14 J
Proportion of total energy consumed in fracture	0.1%	61.5%
Residual energy after fracture	2.9 × 10−11 J	1.0 × 10−14 J
Kinetic energy of launch3	2.7 × 10−12 J	3.4 × 10−16 J
Proportion of residual energy converted to kinetic energy of launch	9.3%	3.4%

¹Calculation based on the change in surface area of Buller’s drop plus exposed surface of hemispherical adaxial drop of same radius coalescing to form single larger hemispherical drop.

²Fracture energy assumed to remain constant for purpose of these calculations, but note that if this decreased by a factor of 10 for H. latitans, separation would consume 6.2% of the total surface tension energy. With the loosening of the connection between the spore and sterigma his, breakage would still remain a greater proportional energetic investment for this species than for fungi with larger ballistospores.

³Kinetic energy based on launch speed predicted from model as described in the text.