Page:Popular Science Monthly Volume 78.djvu/17

Rh in the Pinal Mountains of Arizona. In the course of my study of this group of agaves with thread-margined leaves I have also encountered a garden plant of about twice the dimensions of A. parviflora and with differently shaped leaves, which has been grown under the name of parviflora but which is not unlikely to prove more closely related to the thread-bearing amoles of central Mexico. The prickly margin and its replacement by detaching threads which characterize parviflora are particularly well shown on the juvenile foliage of offsets from this plant.

The other and still smaller dwarf first came into the market under the trade name Agave pumila—given because of its minute size—about thirty-five years ago, the earliest mention of it that I find being in a catalogue published in 1877. No record is available as to the source of the plants then or now in commerce, though I have been told that a collector of such plants has seen it in the Andes of Colombia. Like many other agaves, this produces offsets freely and is now rather extensively cultivated. It was named in 1888 by Mr. Baker, who stated that his plant—about as large as the one here shown—had not increased appreciably in size for the eight years during which it had been cultivated at Kew. Though I have no doubt that it grows to something more than this walnut-size, I shall be surprised if it ever reaches the proportions of parviflora. It is known in botanical literature only from the original description. Its very thick leaves have short, sharp end-spines, decurrent on the margin in a dried line of the same texture as the little marginal prickles. From the fact that this margin was not continuous, Mr. Baker was led to range Agave pumila in his submarginate