Psilopilum idei Broth, ex C. Mull., Bull. Herb. Boiss. 6: 26. 1898.
Illustration: Brotherus (1905).
The bryological literature contains references to the rhizoidal calyptra of
Oligotrichum javanicum (Hampe) Dozy & Molk., despite the fact that Hampe
(1844) described the calyptra of Catharinea javanica as "glabra." Fleischer
(1922) described the calyptra of 0. javanicum as "gross, mit dem hellrotlichbraunen
Filz die ganze Kapsel und das obere Setaende einhiillend." I found four
loose calyptras of this sort in one of Fleischer's own specimens of this species
(FH!) but these surely belong to the four included plants of Pogonatum clavatum
Dozy k Molk. In two other packets I found Oligotrichum javanicum plants with
attached, golden-yellow, almost glabrous calyptras.
Fleischer's comparison of O. javanicum to O. semilamellatum (Hook, f.) Mitt.
must have led Brotherus (1925) to ascribe a "Haube dicht behaart" to both
species. I have seen numerous specimens of the protean Oligotrichum falcifolium
( = O. semilamellatum auct. pl. non Polytrichum semilamellatum Hook, f.),
including the type specimen of Polytrichum falcifolium Griff. (K!), and none
bore rhizoidal calyptras. The true O. semilamellatum seems to be represented
only by its type (K! NY!) which bears green capsules, but unfortunately, no
Oligotrichum falcifolium is frequently intermixed with small Pogonatum
species, and it is often difficult to distinguish between them in dried material.
This may account for Gangulee's recently described Oligotrichum semilamellatum
var dar feeling en sis (1969), said to have a calyptra "dense pilosa, magna, capsulam
penitus operiens." It is not impossible that the northern Oligotrichum species may
be connected with Pogonatum through O. armatum Broth., thus relating the two
groups of Polytrichaceae with compound peristome teeth. If such were the case,
we might expect an Oligotrichum with a rhizoidal calyptra. I have already suggested,
however, that because compound teeth are not consistently produced by
some Oligotrichum .species, the significance of this character is somewhat doubtful.
Oligotrichum parallelum is the type species of sect Pseudo-Catharinaea Brotherus
(1905), but apart from the larger size of the gametophyte, this species is not
sufficiently different from O. aligerum, for example, to constitute an independent
section of the genus.