Spikes, 285.
Spilanthes, 572.
Spinach, 371.
Spinacia, 371, 372.
Spindle-tree, 444.
Spiræa, 151, 451, 456, 457, 460.
Spiræeæ, 457.
Spiranthes, 331.
Spirilla, 27.
Spirillum, 30.
Spirochætæ, 27.
Spirochæte, 28, 38, 40.
Spirodela, 307.
Spirogyra, 44, 45.
Spirolobeæ, 371, 400.
Spirotænia, 44.
Spirulina, 24.
Splachnaceæ, 197.
Splachnum, 196, 197.
Spondias, 439.
Sponges, 8.
Sporangia, 239.
Sporangial-layers, 88.
Sporangiocarp, 88.
Sporangio-fructification, 87.
Sporangiophore, 88.
Spores, 10. Liberation and Distribution of, 91. Germination of, 93.
Sporidia, 112.
A Handbook of Systematic Botany · The Wunder Library — complete classics, free to read, with narration.