1882-83.] Edinburgh Naturalists' Field Cluh. 47 



{seta), as Fuiiaria hygroiuetrica, which in dry weather becomes so 

 twisted that it resembles a piece of rope. Many others derive 

 their names from some peculiarity in the veil (calyptra), as Poly- 

 trichum, many-haired, hairs lying flat on the calyptra as if it were 

 thatched. Also Orthotrichum, straight-haired, the upper part of 

 the calyptra being covered with hairs all projecting upwards. This 

 same principle of designation is freely adopted in later synopses, 

 where you find the names Atrichum, Antitrichum, and Oligo- 

 ti'ichum. Another name, Glyphomitrium, describes a calyptra 

 furrowed or sculptured ; and the name Encalypta describes the 

 seed-vessel as within the calyptra, and hidden by it, and hence is 

 known by the name Extinguisher-moss. Other Mosses derive their 

 names from differences existing in the jyeristome, and include a greater 

 number than any other family does. We need not wonder at this, 

 for the peristome exerts an important influence in the propagation 

 of the plant. It not only affords protection to the spores when the 

 lid falls off, but disperses them when they are matured. This deli- 

 cate and sensitive part of the plant is wonderfully flxscinating. 

 When once the beauties of the peristome open to the mind, the 

 desire to investigate them becomes wellnigh irresistible. The seg- 

 ments of which this fringe is composed conform to a singular law 

 of numbers, the number being either four or a multiple of four, 

 — never less than four, never more than sixty-four, and never includ- 

 ing any intermediate numbers excepting sixteen and thirty-two. 

 Of the plants which derive their names from this source, we men- 

 tion Dicranum (forked teeth), Cinclidotus (teeth with lattice- work 

 at base), Tortula (twisted teeth), and all those which in the older 

 and in the more recent nomenclature end in some form of the Greek 

 word odous, a tooth — as Amblyodon, Ceratodon, Cyrtodon, Didy- 

 modon, Orthodontium, Leucodon, Leptodon, and Zygodon. These 

 examples suffice to show that all muscologists have regarded the 

 peristome as possessing a strong claim to furnish names for the 

 plants. 



II. The second general principle which has been observed in 

 designating Mosses is altogether different from that we have con- 

 sidered. That described something about the plant itself ; this has 

 its origin in the human element as it is related to the plant, — either 

 identifying . the plant with the person who was fortunate enough 

 to discover it, or acknowledging eminent service in the study of 

 muscology, or doing honour to those who have expressed generous 

 sympathy with those who have pursued this branch of science 

 under difiiculties. Hence some of the choicest Moss plants, in the 

 names they bear, perpetuate the memory and service of distinguished 

 men. There are at least ten of this class. Three of these repre- 

 sent Britain, one America, one Flanders, and five Germany. The 



