ACTA BOTANICA NEERLANDICA, Vol. 3 (I), 1954 Acquisitions to the moss and liverwort flora of the Netherlands BY E. AgsteribbeJ.J. Barkman S. Groenhuijzen W.D. Margadant W. Meijer AND N.E. Nannenga-Bremekamp (Received Nov. 12th, 1953) A growing interest in the study of the bryophytes has become evident in the last decade. This interest has been strongly stimulated by the excursions which the has held many “Bryologische Werkgroep” nearly all over the country. Moreover, the fact that bryophytes are in habitats has dominant some special (tree trunks, Sphagneta) few in induced quite a biologists, interested plantsociology, to study them This revival has led results in the intensively. to many investigation of in the of number and our moss flora, particularly discovery a of new rare species. An earlier publication (N.K.A. 57: 281, 1950) has already given number have been dealt a number of these and an additional briefly with in the periodical “Buxbaumia”. There is another circumstance which has contributed to a better of knowledge of our bryophytes. The strong growth our population demand for arable land. has caused a great Consequently, many waste lands have been reclaimed, bogs and marshes drained, brooks canalised, etc. It therefore became imperative to preserve as many of Their value our incomparable moors, marshes, etc. as possible. as had first be assessed from future nature reserves to an accurate survey of their fauna and flora. Naturally this also included the bryophytes. It be that cannot gainsaid a general impoverishment of our moss flora has taken place in the course of the last century. Many tracts of wild land have disappeared whilst the increasing industrialisation of the has made unsuited for the of country large areas growth mosses. which limited Many species were quite common a century ago are now few localities Antitrichia and Neckera while to a e.g. curtipendula pumila, become extinct: other, rarer mosses have probably e.g. Splachnum ampullaceum and Cinclidium stygium. It is to be feared that this impoverish- ment will proceed at an increasing rate in the future. Nevertheless well a number ofnew indigenes have been discovered as as an additional number of rare and remarkable species. This publication mentions 13 Musci and 5 18 new indigenous species, of which are Hepaticae. In addition it mentions 5 new varieties (Musci) of which 3 are new and to science, and 20 new records of rare bryophytes (14 of mosses 6 of liverworts). 125 ACQUISITIONS TO THE MOSS AND LIVERWORT FLORA OF THE NETHERLANDS SPECIES AND VARIETIES NEW TO OUR FLORA A. Musci Barbula gracilis Schwaegr. Leg. A. J. H. M. van de Ven, 1-10-1949, Achtbundersweg, V6. of in Mesobrometum 23.13, Schin-op-Geul, prov. Limburg, a on cretaceous limestone (Maestrichtien). Most of the differences between Barbula gracilis and Barbula fallax, Dixon much indicated by (1924), are unreliable: both have the nerve the leaves the ventral protruding at the back of and often quite flat on neither the there between side; in of species is a difference the leaf those the short in cells on the nerve and on lamina; they are very the of the less towards the both upper part leaf, more or elongated base, and As rule those in Barbula remain on nerve lamina. a fallax very short the while those Barbula to base, of gracilis are distinctly longer near the base. In the material from S. Limburg, however, the basal cells but the in from are short, same was observed by me an exsiccate Upsala (Sweden). On the other hand, exsiccates of B. fallax, collected by Brotherus, proved to have much elongated basal cells! In the most reliable differences between Barbula my opinion gracilis and Barbula fallax are the smooth leaf cells of the former in contrast to the papillose cells of the latter, and the position of the leaves: in Barbula gracilis straight and closely appressed when dry, erecto-patent when moist, in Barbula fallax somewhat twisted when dry, squarrosely recurved when moist. Generally too, the leaves of Barbula gracilis have is sometimes a longer and narrower acumen and a nerve which excurrent. J. J. B. Barbula sinuosa Braithw. Leg. J. J. Barkman, no. 3699, 10-10-1951, N. of Deventer, M6. of the base of in foreland 65.22, prov. Overijsel, on a pollard-willow of river IJsel, flooded in winter, rel. 1 1397. Moenkemeyer includes this Although (1927) species as a variety of Barbula cylindrica (Tayl.) Schimp., I consider it distinct enough to give it specific rank; see also Dixon (1924: 215-216). J. J. B. Bryum capillare Hedw. var. rosulatum Mitt. Linde Leg.J. J. Barkman, no. 3685, 7-8-1951, valley, Oldeberkoop, of of Fraxinus in moist ash-alder- K6.15.22, prov. Friesland, on stumps coppice, rel. 1085. The aspect of this variety is strikingly similar to that of Rhodobryum in roseum. The leaves are crowded a terminal rosette, squarrosely recurved when moist, shrinking, but widely spreading and not spirally twisted when dry, very large (3J-4£ mm long), with entire, recurved and margins mostly percurrent nerve. J. J. B. 1 In this “rel.” stands for “relev6” paper plantsociological (sample plot survey). 126 E. AGSTERIBBE, ETC. Bryum funckii Schwaegr. H. M. Leg. A. J. van de Yen: 1-10-1949, Wahlwiller, V6.33.42, of initial of Mesobrometum loose prov. Limburg, stage on cretaceous marl (Gulpcns); 30-9-1949, Schiepersberg between Bemelen and Houthem, V6.21.23, prov. of Limburg, Mesobrometum on cretaceous chalk rocks (Maestrichtien). Both have about 1 catenulate samples cm. long, very fragile, stems. of the size and i.e. small All leaves are same shape, very (0.5 mm long and of thin with but nearly as broad), a very texture, concave flat, not recurved, entire margins without border. The leaf cells are all wide, shortly hexagonal and thinwalled. The nerve is strong, reddish at base, otherwise dark green or brownish, ending in apex or excurrent short in a apiculus. This is a calciphilous species, known from Central-Europe, so it could be expected here. whether — Quite a different matter is the question this species like other of based so many species Bryum exclusively on gametophyte characters — be looked sound In can upon as a species. my opinion it is quite possible that Bryum funckii merely represents a variety of either Bryum argenteum or Bryum caespiticium. J. J. B. Calliergon megalophyllum Mikutowicz of Brabant. Leg. W. Meyer, April 1948, Belversven, prov. N. In the last five mentioned years Calliergon megalophyllum, a species by Mikutowicz in his Bryotheca Baltica, no. 141 (1918), has received attention from the Scandinavian bryologists Tuomikoski (1937, 1940) and Jensen (1939). At first sight the differences between Calliergon megalophyllum, richardsonii that Calliergon giganteum and Calliergon seemed so slight to me, the rank of first named. I was dubious as to specific the However, through the kind intervention of Dr Persson I was able to send all Dutch material Dr who named of my Calliergon to Tuomikoski, one and sent me fine Finnish my specimens Calliergon megalophyllum samples for The his material of the comparison. study of quite convinced me specific rank of Calliergon megalophyllum. Calliergon megalophyllum differs from Calliergon giganteum in the absence of the numerous lateral branches with smaller leaves so characteristic of the latter, and by the smaller auricles not reaching is less than in the nerve. The nerve itself pronounced Calliergon richardsonii it be known the giganteum. From Calliergon may by longer the the instead of a red nerve reaching apex, green colour, tendency in Calliergon richardsonii, and the dioicous inflorescence. has been from Up to now Calliergon megalophyllum reported Norway, and Tuomikoski and Sweden, Finland Russia by (1940), was supposed to be boreal-continental. This new record from Holland is far to the southwest of the known localities. The habitat of Calliergon megalophyllum in the Belversven is similar to of the Scandinavian stations. The of the most pH open water ranged 127 ACQUISITIONS TO THE MOSS AND LIVERWORT FLORA OF THE NETHERLANDS 6.6-7.0 from (Van Heusden, 1949). Our Calliergon was found along the fen Carex margin, 1-2 dm submerged, among inflata, Phragmites communis, Schoenoplectus lacustris, Glyceria spectabilis and Sparganium minimum in the upper herblayer, and Menyanthes trifoliate and Comarum palustre in the lower herblayer, while Hydrocharis was floating. W. M. Dicranoweisia crispula (Hedw.) Lindb. Leg. W. D. Margadant and N. E. Nannenga-Bremekamp, herb. N.E.N.-B. of no. 1079, 15-8-1950, Hoge Veluwe, prov. Gelderland, on concrete wall. From dark about a single very compact, greyish tuft, growing m collected. This up an exposed concrete wall, a part was sample proved to be different from the in the Netherlands common Dicranoweisia cirrata in the following points: the longer narrower leaves with plane margins and the small inflated auricles. We therefore refer this specimen to Dicranoweisia crispula. Geographically the occurrence of this mountainous species here is Fig. 1. Dicranoweisia crispula (Hedw.) Lindb. 1. Sterile plant. 2. Leaf. 3. Leaf auricle. 4. Cross sections of leaves. 5. Leaf cells. 6. Ditto, near the base, showing elongated cells next to the nerve. 128 E. AGSTERIBBE, ETC. it have been with the Maulbrunner remarkable; may imported sandstone, which was deposited in the vicinity of the wall, but on which found. On the other hand it have arrived our moss was not may by wind from more mountainous regions, perhaps via isolated rocks in the Northern German Plain from where there are some records too. (Fig. 1) W. D. Marg. and N. E. N.-B. Dicranum fuscescens Turn. var. falcifolium Braithw. of Leg. W. Meyer, April 1950, Speulderbos, N5.17.24, prov.