スギゴケ科の仮根系(第9回大会講演要旨)

抄録

1) The rhizoid systems of the Polytrichaceae were examined, utilizing mainly indigenous material of various species. 2) In Atrichum rhystophyllum the system consists of two types of rhizoids. The first type is slender (less than 10μ thick), tapering, and so numerous and interwoven as to cover the whole surface of the underground portion of the stems. The second type is thick (12-20μ, not tapering, growing horizontally, brownish with age, and rather few in number. 3) Only the second type forms rhizoid bundles which are frequently branched and freely develop new erect shoots. Thus the aerial shoots in a mat are connected under-ground by the rhizoid bundles-in this respect the mat is a miniature of a bamboo thicket and a mat (not a single shoot) should be regarded as an individual. 4) The bundle is always dextrorsely twisted like a right-handed rope. This is true not only in Atrichum rhystophyllum but also in all other examined species of the genus including exotic ones. 5) The thick bundle often consists of more than 100 filaments. The inner filaments are united to each other and form a "tissue" like medulla. 6) The rhizoid bundles are present in all examined species of Oligotrichum, Pogonatum, Polytrichastrum and Polytrichum-even in Pogonatum spinulosum where the protonema is persistent and the gametophore is highly reduced. In these genera the twining is not so distinct but filaments in a bundle run almost straight and nearly parallel to each other. 7) The rhizoid system of Bartramiopsis lescurii is quite different from that of other genera. The rhizoids are very thick (up to 35-40μ, deep reddish brown and bearing numerous papillae on the surface. Distinct rhizoid bundles are not found but the thick rhizoidal filaments are often covered by slender (3-5μ thick), hyphae-like branches which are variously oriented.