190 
pRere 
woody and herbaceous plants (within the limits 
tive percentages o : 
of hardiness at Brooklyn) in the various families, orders, and larger 
subdivisions of the Plant Kingdom. Thus, for example, it will be 
seen that im the group of the Poppies and their relatives (Papa- 
verales) there are no trees or shrubs hardy in Brooklyn; in the 
group of the Roses and their relatives (Rosales) there is a gen- 
crous proportion of both woody and herbaceous plants ; while in the 
Horsechestnut and Willow groups (Sapindales and Salicales ) 
there are few if any herbaceous plants hardy here. Among the 
Gymnosperms there are no herbaceous plants. 
The following great groups of plants are represented in the 
Systematic Section. 
Thallophytes 
Algae, About fifty genera of Algae are found in the Botanic 
Garden, mostly in the Lake and Brook. These include Blue 
Green Algae, such as Glococapsa, Nostoc, and Oscillatoria ; and 
Green Algae, such as Pleurococcus (on surface of rocks, tree 
trunks, ete.), Vlothrix, Oedogoniuim, Vaucheria, Spirogyra (Pond 
scum), and /fydrodictyon (Water Net), common in our Brook. 
Lichens and Fungi. From time to time Lichens and Fungi are 
on exhibit in the Moss Ravine. 
Bryophytes 
Liverworts and Mosses are grown in the Moss Ravine. 
Fern Allies 
In the Moss Ravine are also a few species of Clubmosses and 
Horsetails. 
Prerns 
West of t 
of plant evolution. Fern fronds are flattened and fused branch 
ie Moss Ravine are Ferns, representing a middle stage 
systems, the primitive form of leaves. 
Seed-bearing fossil plants related to the Ferns are known. 
They were at first called Pteridosperms (ferns that bear seeds ). 
From the fact that they are related to both the cycads and the 
ferns they have been called Cycadofilicales. 
