REVUE BRYOLOGIQUE. 9 
on this head, and must content myself with a brief notice of 
it, referring the student to the plants themselves for proof 
of whal I allege. One of these bifarious species is Marsupella 
decipiens Massal. (— Sarc. Funckii v. decipiens Mass. = S. 
Funkii G. et R. Hep, Eur. no. 616 ! ) : an excellent example 
of the transition. Another is Mars. conferta (Limpr. !) first 
described as a Sarcoscyphus, but afterwards relegated by the 
author to Gymnomitrium. In specimens from Limpricht him- 
self, the only fertile involucre I was able to examine bad a 
tubalar perianth, but reduced to a short multilobulale cup. — 
Of Gymn. adustum Nees ( verum, fide Limpr.) I have examined 
specimens from Limpricht, besides those in G. et R. Hep. 
Eur. no. 648 (in Pearson’s copy), and others gathered lately 
by M Pearson in Wales; all of which seem plainly of the 
same species, yet all show considerable variation in the de- 
velopment of the perianth. The latter consists of two (rarely 
onc or three } small leaves, either free or in various degrees 
of union ; sometimes nearly combined into a tube with a cu- 
cullate apex. They are usually adnate 19 the involucre at the 
base , to a greater or less beight — rarely quite free. Calyp- 
tra adnale to perianth and involucre, sometimes s0 far up 5 
that only the apex is free and is crowded with sterile pistilli- 
dia, — In Gymnom. crassifolium Carr. the {wo fertile involucra Re 
I examined had both as perfect a tubular perianth — in one 
case scarcely shorter than the involucre — and as truly 
adherent at the back, as in Marsupella emarginata (Ebrh.). 
Corresponding variations of struclure , and abortions, oc- 
eur in every tribe of Hepaticæ. Whoever has examined a 
reat number of species, from all parts of the world, must 
have met with frequent instances of imperfeetly formed, and 
even of almost obsolete periantbs , and have noted that such 
rudimentary envelopes are not unfrequently associated with 
perfect fruit. I could cile hundreds of such cases, but it may 
suflice to refer the student to the genus Plagiochila, where 
they may frequently be observed : especially in PL hypnoides 
and allied species, which so abound on the branches of 
young trees in deserted clearings on the Amazon that they 
may properly be styled « weeds ». In all these it is nol rare 
te see perianths more or less defective — often slit down 
one or both sides, almost or quite to the base , or reduced to 
a short ciliated rim, or variously malformed — yet oflenin- 
_cluding a perfect calyptra and capsule. Parallel instances are 
occasionaily met witb in various European Jungermanideæ, 
_ but are too often thrown aside in disgust by the observer, as 
 monstrosities ; when it is precisely these abnormal structures 
hrow light on what was obscure before in the 
of so-called « normal forms » or reveal unsus- 
