Fig. 4
From: The morphological diversity of pollen in the genus Gossypium
Dendrogram of Gossypium based on pollen characteristics (A). Three pollen types (right): Type I, big pollen size, long spine length, low spine density and little protuberance (B); Type II, small pollen size, short spine length, low spine density, and obvious protuberance (C); Type III, small pollen size, short spine length, high spine density, and little protuberance (D). Scale bar: 50 μm. Accelerating voltage: 15 kV