F r e q u e n t ly , on th e i r f a llin g aw a y from th e le a v e s , a s in J . excisa {S uppl. ta b . 2) a n d som e
o th e r s , th e le a v e s a p p e a r in ju r e d a n d j a g g e d , a s i f th e c e llu le s h a d b e e n to rn o ff; a n d it
is n o t im p ro b a b le b u t th a t , in c e r ta in s ta te s o f th e p l a n t , th is m a y r e a lly b e th e c a s e ; so
th a t e a c h o f th e s e p a r tic le s m a y b e lo o k e d u p o n a s a c e llu le . T h e i r c o lo r, w h e n firs t
fo rm e d , to o , is g e n e r a lly g r e e n , tu r n in g to b row n in a n o ld e r s ta te , a s in J . n emorosa, a n d
to a fin e r e d in J . exsecta.
S E C T IO N I I I .
On Jungermannia as a Genus, and on the Arrangement o f
the B ritish Species.
A s f a r a s m y e x p e r ie n c e e n a b le s m e to offer a n o p in io n , from m y a c q u a in ta n c e w itii
th e B r i t i s h a n d m a n y fo re ig n sp e c ie s , th e p la n ts th a t a t p r e s e n t fo rm th e g e n u s J o n g e r -
MANNiA, h ow e v e r n um e ro u s , c a n n o t b e d iv id e d in to o th e r g e n e r a b y m e a n s o f c h a r a c te r s
ta k e n m e r e ly f rom th e f ru c tific a tio n . I n th is r e s p e c t, th o s e w h ic h s e em m o s t a llie d in h ab it,
o fte n d iffe r e s s e n tia lly ; so th a t , w ith r e g a r d to th e JungermaimicE fro n d o sa , fo r e x am p le ,
w h ic h a t f ir s t s ig h t a p p e a r to d em a n d a s e p a r a tio n , u n le s s t l ie r e a r e m a d e a lm o s t a s m a n y
g e n e r a a s sp e c ie s , I d o n o t k n ow a n y c h a r a c t e r w h ic h th e y h a v e in com m o n , b y w h ich
th e y m ig h t b e d is c r im in a te d from th e J u n g e rm a n n ia fo lio sa .
J u n g e rm a n n ia nemorosa, r e su p in a ta , umbrosa, a n d u n d u la ta , h a v e a p e c u lia r h a b it a b o u t
th em , a n d h a v e , m o re o v e r , a r em a rk a b ly c om p r e s s e d c a ly x , t ru n c a te a t th e m o u th ; a n d
w e m a y t h in k h e r e to h a v e d is c o v e re d a c h a r a c t e r b y m e a n s o f w h ich th e y m a y b e rem o v e d
from th e r e s t o f th e g e n u s ; b u t a n e x am in a tio n o f o th e r s p e c ie s will co n v in c e u s o f th e
in a d e q u a c y o f th is c h a r a c te r ; sin c e J . asplenioides a n d J . com planata, tw o p la n ts v e ry
d iffe re n t in o th e r re s p e c ts , h a v e a c a ly x o f th e s am e sh ap e .
A s till s t ro n g e r p e c u lia r ity o f h a b it s e em s to u n ite J . se rp y llifo lia , J . h am a tifo lia ,
J . calyp trifoU a , a u d J . m in u tissim a , in w h ich a lso th e s in g u la r s t r u c tu r e o f th e c a p su le , a n d
e sp e c ia lly its s h o r t v a lv e s , s e em s to c la im fo r th em th e p r iv ile g e o f b e in g c o n s id e r e d a
d is tin c t g e n u s ; y e t th e r e a r e tw o sp e c ie s , J . M a c k a ii a n d J . p la ty p h y lla , w h ic h co n n e c t
th em b y a n e a sy g r a d a tio n w ith J . d ila ta ta a n d J . T amarisc i.
T h e fo llow in g c h a r a c t e r o f th e g e n u s I w o u ld p ro p o s e a s lia b le to f ew e r o b je c tio n s
th a n a n y th a t h a s y e t b e e n g iv e n .
C L A S S A N D O R D E R .
C r y p t o o a m i a , H e p a t i c ® . S ckreb.
(N A T U R A L O R D E R .
H e p a t i c ® . J u s s . D e Ca n d . P l a n t ® C r y p t o g a m ® , C a l y p t r a t ® , D f . o p e r c u l a t® . Mo h r.)
G E N E R IC C H A RA C T E R .
R e c ep ta cu lum f ru c tu s c om m u n e n u llum .
Cal. P e r ic h a tium m o n o p h y llum tu b u lo s um , r a r iù s n u llum .
I N T R O D U C T I O N .
C a l y p t r a g e rm e n te g e n s , apic e a d c a p su lam em itte n d am v e r tic a litè r r um p e n s , s ty llg e r a .
[ p e d u n c u la ta , o v a ta v e l sp hæ ric a , in v a lv a s q u a tu o r , p lù s m in û sv e lo n g a s ,
lo n g itu d in a litè r f is s a ; r a r is s im e e n o rm itè r d is ru p ta .
Columella n u lla .
S em in a filis s p ir a lib u s e la s tic is im m ìx ta .
C h a r . E s s e n t i a l i s . R e c ep ta cu lum f r u c tù s c om m u n e n u llum . P e r ia n th ium m o n o p h y llum ,
tu b u lo sum . Capsula p e d ú n c u lo c a ly c e lo n g io r i in s id e n s , q u a d riv a lv is .
T h i s d is tin g u is h e s i t a t o n c e f rom M a r c h a n tía , b y th e a b s e n c e o f th e common
re c e p ta c le fo r th e f ru c tific a tio n : from J n th o c e ro s , by th e fo u r -v a lv e d c a p su le , a n d th e
w a n t o f a c o lum e lla : from T a rg io n ia , b y th e m o n o p h y llo u s c a ly x ; a n d from R ic c ia a n d
Spharo ca rp u s, b y th e lo n g fo o ts ta lk s o f th e c ap su le s . I n d e e d , w e re i t n o t fo r th e
an om a lo u s c a p su le o f J p u s illa , th e U n n æ a n c h a r a c te r , “ capsula q u a d riva lv is,'’ w o u ld , I
th in k , b e a dm ira b ly c h a r a c te r is tic o f th e w h o le g e n u s .
Ï sh a ll n ow offer a n A n a ly tic a l T a b le o f th e s p e c ie s d e s c rib e d in th e p r e s e n t w o rk ,
a r r a n g e d , in som e d e g r e e , a c c o rd in g to a m e th o d em p lo y ed b y L am a r c k a n d D e C a n d o lle
in th e i r Flore Française, w ith a lte r a tio n s p r in c ip a lly s u g g e s te d b y m y v a lu e d f r ie n d ,
M r . L y e l l ; a n d I sh a ll th e n p ro c e e d to g iv e fu ll a n d am e n d e d c h a r a c te r s o f th em , w ith
a d d itio n a l n o te s a n d sy n o n ym s , w h ic h w ill c o n c lu d e th is In tro d u c tio n , a lr e a d y , p e rh a p s ,
c a r r ie d to to o g r e a t a le n g th .