A group of green algae, distinguished mainly on the basis of ultrastructural morphology. The sea lettuce, Ulva[?], belongs here. They are divided into the following groups:
... Waldeck, (1766-1875), French antiquarian, artist, explorer
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Sir Francis Younghusband, (1863-1942), India and Tibet
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Zhang Qian[?] - spent 12 years starting in 138 ...