190 
Pogonia verticillata (Willd.) Nutt. Testa oblong, about six 
times longer than thick, averaging 1.16 X 0.176 mm. Cells ob- 
long, about five times longer than broad, averaging 0.110 X 0.0236 
mm. (Plate CLII., fig. 21.) 
Pogonia affinis, Austin. Testa oblong, about six and a half 
times longer than thick, averaging 1.183 X 0.170 mm. Cells ob- 
long, about five times longer than broad, averaging 0.117 X 0.0255 
mm. (Plate CLII., fig. 22.) 
15. Orcuis, L. 
Orchis spectabilis, L. Testa oblong, slightly tapering at ends, 
about four and a half times longer than thick, averaging 0.57 0.12 
mm. Cells regular, oblong, about five times longer than wide, 
averaging 0.117 X 0.022 mm. (Plate CLIL., fig. 23.) 
16. HaBenariA, Willd. 
flabenaria ciharis (L.) R. Br. Testa oblong, about two and a 
half times as long as thick, averaging 0.452 X 0.18 mm. Cells 
oblong or polyhedral, about three times longer than wide, averag- 
ing 0.0496 X 0.0157 mm. (Plate CLIL., fig. 24.) 
17. CYPRIPEDIUM, L. 
Cypripedium pubescens, Willd. Testa elongated-fusiform, about 
five times as long as thick, averaging 1.35 X 0.25 mm. Cells ob- 
long, about five times longer than wide, averaging 0.14 X 0.023 
mm. (Plate CLIL., figs. 25, 25a.) 
In determining species the seeds are not an uncertain element. 
While it would not be possible to take any one seed, and from it 
alone locate its position, not a collection of seeds from any fruit 
has failed to indicate such pronounced individual characters as to 
render a confusion of species possible. Consider, for example, 
such troublesome species as Peramium repens and P. pubescens. 
While the generic features are pronounced in all the seeds, in each 
species is apparent certain individual characters that sharply 
separate them. The more graceful proportions and nicer fitting 
of cells, together with their elongation and narrowness, easily dis- 
tinguish Peramium pubescens. In Peramium repens the cells are 
shorter, often quite equilateral and intercellular spaces abound. 
In the species of Listera examined the same specific differences 
exist. In Liéstera cordata is noted a decided departure from Listera 
