Affinities of Taenitis.—The genus Taenitis is one that has always puzzled botanists. It was once placed in the tribe Grammitideae along with such genera as Notholaena, Brainera, Meniscum, Vittaria, Hemionitis and Drymoglossum, and it has also been considered sufficiently distinct to stand as the type of a tribe named for it, while recently it has been considered as a member of the tribe Polypodicae. Now comes E. B. Copeland in the Philippine Journal of Science and gives the genus another turn and this time places it in the Davallieae largely upon the relationship shown by the internal structure of the stem and the character of the scaly covering. It is likely that the new manipulator of the genus is as near right as anybody. The main thing is to discover what are the real indications of relationships. With some students it is venation, with others the shape and position of the indusium, with others the character of the vestiture and still others may have other rules by which to judge. When we agree upon the proper earmarks, anybody ought to be able to put the ferns in their proper groups.
Sporophyll Zones.—The fact is well known that some of the club-mosses, notably the shining club moss (Lycopodium lucidulum) and the fir club-moss (L. Selago), bear their sporangia in bands or zones that alternate with regions on the stem in which there are no sporophylls, but it does not seem to be equally well recognized that the same phenomena are found pretty generally among the ferns. If one will examine the crowns of the cinnamon fern, it will be readily seen that sporophylls and vegetative leaves form alternating circles. Curiously enough, the fertile fronds, which appear at maturity within the circle of sterile leaves, really belong to the outer circle, as befits the group that is to develop first. The sensitive and ostrich ferns are other species in which the zones of fronds are very distinct. So pronounced is this, and so far has each kind developed before unfolding, that each is usually incapable of taking up the functions of the other in cases where the destruction of one kind makes such exchange necessary or desirable. From efforts on the part of the plant to supply vegetative tissue to leaves designed originally for spore-bearing, only, we owe the various “obtusilobata” forms occasionally reported. The differences in zonation here mentioned are most pronounced in ferns with dimorphic fronds, but evidences of the same thing, more or less distinct may be found even in those ferns that have the fertile and sterile fronds essentially alike in outline. As a usual thing, the spore-bearing leaves are produced after the vegetative leaves have unfolded and when we find a plant in full fruit in late summer, that lacked spores in spring, it is due to the developing of the fertile leaves later. This is especially true and most noticeable in ferns that produce their fronds in crowns, but even in those species with running rootstocks, we commonly find evidences of zonation. Following out the idea of zonation we find among many of the fern allies that not only are the sporophylls assembled in zones but the zones terminate the central axis or branch. Under such circumstances the shoot begins to take on many of the characteristics of the flower and if we allow the definition of a flower as a shoot beset with sporophylls, it really is a flower. In the plants in which the flower comes to its highest development this structure is essentially a group of two kinds of sporophylls set round with sterile leaves called petals and sepals. Did ferns, instead of selaginellas, produce two kinds of sporophylls, the whole fern plant with its crown of fronds, would be very like a flower.
INDEX TO RECENT LITERATURE.
Readers are requested to call our attention to any errors in, or omissions from, this list.
Clute, W. N. Nephrodium deltoideun. illust. Fern Bulletin, Ja. 1912.
Clute, W. N. Rare Forms of Fernworts.—XXI. Another Form of the Christmas Fern. illust. Fern Bulletin, Ja. 1912.—Polystichum acrostichoides f. lanceolatum described and illustrated.
Darling, N. Observations on some Lycopodiums of Hartland Vt. illust. American Fern Journal, Ap. 1912.
Dodge, C. K. The Fern-flora of Michigan. Fern Bulletin, Ja. 1912.—Fifty-eight ferns and thirty-one fern allies listed with notes.
Cockayne, L. Some Noteworthy New Zealand Ferns. illust. Plant World, Mr. 1912.
Hill, E. J. Additions to the Fern-flora of Indiana. Fern Bulletin, Jl. 1912.—New stations for several species.