126 MISSOURI BOTANICAL GARDEN. 
Botanical Garden, natural size. —1, Y. filamentosa; 2, Y. flaccida glau- 
cescens. 
Plate 13. — Yucca flaccida glaucescens, cultivated in the Missouri Bo- 
tanical Garden. — Producing racemose secondary inflorescences, in addi- 
tion to the central panicles. 
Plate 14. — Yucca flaccida glaucescens, cultivated at the Missouri 
Botanical Garden, showing thermotropism of inner leaves.— 1, Normal 
position of leaves, at a temperature slightly above the freezing point; 
2, Leaves inrolled, at 26° F. 
Plate 15.— Yucca flaccida glaucescens, cultivated at the Missouri 
Botanical Garden. — Photographed by P. T. Barnes. 
Plate 16. — Yucca flaccida, near Anniston, Ala. 
Plate 17.— Capsules, natural size.—1, Yucca flaccida glaucescens, 
cultivated at the Missouri Botanical Garden; 2, Y. tenuistyla, Industry, 
Tex., Lindheimer. 
Plate 18. — Yucca tenuistyla, near Sealy, Tex. 
Plate 19. — Yucca tenuistyla from near Sealy, Tex. Small sized flowers, 
natural size.— Photographed by P. T. Barnes. 
Plate 20. — Yucca constricta. — 1, Cultivated at the Missouri Botani- 
cal Garden from Seward Co., Kas.; 2, Near Uvalde, Tex. 
Plate 21.— Capsules, natural size. — 1, Yucca constricta, Cline, Tex. ; 
2, Y. radiosa, Benson, Ariz. 
Plate 22. — Yucca radiosa, at Benson, Ariz. Fruiting plants and an 
exceptionally symmetrical young plant. 
Plate 23. — 1, Yucca angustissima, a type sheet in the Engelmann her- 
barium; 2, Yucca glauca, near Albuquerque, N. M. 
Plate 24. — Capsules, natural size. — 1, Yucca angustissima, from near 
the Grand Cafion, Ariz.; 2, Yucca glauca, from Manitou, Col. 
Plate 25.— Yucca glauca, cultivated in the Missouri Botanical Garden. 
Plate 26.— Yucca glauca stricta, cultivated in Tower Grove Park, 
St. Louis, from Seward County, Kas. 
Plate 27.— Flowers of Yucca glauca stricta, natural size, from the 
preceding. — Photographed by P. T. Barnes. 
Plate 28.— Yucca Harrimaniae, at Helper, Utah. 
Plate 29. — Yucca Harrimaniae, Helper, Utah, — Capsules, natural size. 
Plate 30.— Yucca Arkansana, near Fort Worth, Tex. 
Plate 31. — Yucca Arkansana, near Dallas, Tex., fruiting plants. 
Plate 32. — Yucca Louisianensis.—1, Near Jefferson, Tex.; 2, Near 
Texarkana, Tex. 
Plate 33.— Yucca Louisianensis, Hughes Springs, Tex. 
Plate 34.— Yucca Louisianensis, Hughes, Tex.—1, Form with slen- 
derer, paler style; 2, Form with very tumid dark green style, slightly 
reduced. 
Plate 35.— Yucca rigida, near Picardias, Mex. 
Plate 36. — Capsules, natural size. —1, Yucca rigida, from Picardias, 
Mex.; 2, Yucca rostrata, from Peyotes, Mex. 
