20 Addisonia 



what each cell; the lance-like central placenta, originally a part of 

 the partition-wall, breaks down distally, so affording a free common 

 egress for the seeds at the opened capsule-apex. The numerous 

 seeds are polyhedrons of five or six faces, gray-brown, the outer 

 seed-coat being conspicuously reticulate. 



Because this is the best-known of all our beard-tongues, and the 

 one that thrives most easily under cultivation, it seems the logical 

 one with which to introduce a series of illustrations and studies of 

 Pensiemon. It may be found in almost any botanical garden, and 

 beyond the suggestion to sow the seed in rich open loam, no directions 

 need be given for its culture. Indeed, that it is capable of thriving 

 quite without attention, the history of its introduction into the 

 eastern United States shows. Only a little over eighty years ago 

 the botanical explorer, Thomas Nuttall, discovered the species of 

 the prairies of the Arkansas River, probably in what is now the 

 state of Oklahoma — to-day it may be seen in sufficient abundance in 

 the pasture-fields about his home-city, Philadelphia. Indeed the 

 strong-smelling, rank-growing foxglove beard-tongue is far from 

 popular with the farmers of that section. 



However, the plant is worthy of all its popularity with lovers of 

 beautiful flowers. The abundance of bloom, the stately dignity of 

 each inflorescence which makes each stalk seem in itself a trophy, the 

 delicacy of outline and purity of color of each flower — all make this 

 a plant the first finding of which the amateur remembers. And 

 for the scientist the study of the inflorescence, flower or fruit gives a 

 wealth of significant detail. 



Pensiemon is one of the largest plant-genera in North America, 

 and, as only one species occurs beyond this continent, the genus 

 might almost be constituted a pan-continental floral emblem. In 

 beauty any one of the species is worthy of such honor — the corolla- 

 form has grace and distinction, and in color there is great variety — 

 a few species are yellow, more are red or white, and the large major- 

 ity are lavendar, purple, or blue, climax-colors of the plant-world. 

 The genus is fundamentally one of the most natural known — 

 the unique stamen-structure especially emphazing the genetic 

 kinship of the whole — yet whatever type of corolla may have been 

 primitive has evolved into a diversity so rich that its interpretation 

 becomes one of the most fascinating problems offered by systematic 

 botany. 



Francis W. Penneli.. 



Explanation op Plate. Fig. 1. — Flowering stem. Fig. 2. — leaves. 

 Fig. 3. — Flower, opened, exposing stamens. Fig. 4. — ^Anther, rear view, X 5. 

 Fig. 5. — Anther, front view, X 5. Fig. 6. — Fruit. 



