roundish areolæ or. cellules, and so regula r in size, as to give the le a f an extremely
beautiful apjieanuice unde r foe microscope. When dry, th e whole surface appears to be
elegantly punctated, in consequence o f th e sinking in o f the centre o f th e cellules, and,
when sa tura ted afresh, a da rk sp o t may be seen in each cellule, where th e coloring
m a tte r has been precipitated. T h e general color o f th e leaves is a n olive-green, more or
less dark, fiequently approaching to black.
Perigonial leaves (f. .5) more crowded and closely imbricated th an th e re st, and th e lesser
lobe is o f a somewhat la rg e r size ; in which particulars alone they differ.
Perichætial leaves (f. 6) also be a r a close resemblance to th e cauline ones, b u t they are
somewhat larger, and are furnished with a lobule nearly equal to one h a lf o f th e size
o f the lobe : th e la tte r is appressed to th e superior, as the former is to th e inferior, surface,
o f th e calyx.
Stipules large, roundish, entire , o r more frequently very obtusely notched, when they may
tru ly be called obcordate.
*Ma l e F r u c t i f i c a t io n ( f . 5 ) .
Anthers (o f vvhich one or two are situated in th e axilla o f each p e rigonia l le a f) ovate
in a younger s ta te , spherical when advanced to th e ir full size, pale grey, reticulated ;
fo o ts ta lk about h a lf o f th e len g th o f the Anther, while, transversely striated.
• F e m a l e F r u c t i f i c a t io n v e ry .g e n e v a lly te rm in a l, occasionally lateral.
Calyx (f. 9) about three-fourths o f a line long, obcordate, much depressed, especially towards
th e extremity ; besides the two angles on the sides, a th ird and more obtuse one projects
from th e under surface, and extends from th e base to th e apex, ( f 6). T h e mouth, in
an early s ta te , appears to be confined to a narrow c entral tu b u la r apiculus, which may a t
len g th be distinctly seen to divide in to four acute teeth, and, a fte r the emission o f the
capsule, a long b ut narrow opening is to be observed, reaching nearly the whole width o f
th e calyx, ( f 9 ). In color and texture, I can perceive no difference between it and the
leaves.
Germen (f. 7) obovate, pale green, having a long tub u la r style.
Calyptra o f the same form with th e Germen, o f a very th in membranous tex tu re , diaphanous,
reticulated. I t opens with an irreg u la r vertical fissure for the emission o f th e capsule.
Peduncle v e ry little indeed exceeding th e len g th o f th e calyx j sometimes not a t a ll:
w h ite , cellulose, cylindrical, a little thickened towards the summit.
Capsule (f. 9) small, exactly spherical, o f a delicate texture , less so indeed th an th a t
o f J . serpyllifolia, b u t more so than those of J . dilatata and Tamarisci; w hitish, so
pellucid th a t a fa in t tinge o f a gre enish-brown color is imparted by th e seeds w ith in ;
marked with reticulations. T h e four ovate valves a re equal in size, and the divisions
extend to th e thickened apex o f the p edunc le ; a fte r the discharge o f the seeds they
become recurved.
Seeds o f an irregula r form, b u t approaching to .spherical, smooth, o f a da rk olivc-grecn
color. T h e spiral fd am enls are brown, formed o f a double helix, enclosed w ithin a
pellucid, tu b u la r membrane, which a t the mouth is a little expanded, a t th e base affixed
lo th e extrem itv o f the inside o f th e valves, where they are pe rsistent in small tu fts , even
a f te r the discharge o f the seeds.
I t is to my friend, Mr. J . T. Mackay, o f th e Botanic garden, Dublin, th a t we owe o u r first
knowledge o f this p la n t; and to him I am anxious to dedicate it. Since this discovery, indeed, it
has been found elsewhere in Ire land, as well as in E n g la n d ; and, in th e south-western pa rt o f our
island, appears to be an abundant species on shaded and moist limestone rocks. In th e numeroue
chasms in th e gro u n d , especially ne a r th e sea, about Torquay and Babbicomhe, in Devonshire,
J . Mackaii grows in such p rofusion, as to form a striking feature in the cotoring o f the p erpendicular
faces o f th e ro c k s : th o u g h it is in more exposed situations only th a t the delicate capsules are to
be found, and, even there, n o t without an accurate examination, on account o f the ir small size.
T h e p resent species, a lth o u g h abundantly distinct, as well {com J . d ilatata as J . serpyllifaba, has,
nevertheless, many characters in common w ith each. T h e former it approaches m general habit
(though, perhaps, i t has a still g re a te r affinity in external appearance with J . complaaaiaj, a nd in the
figure o f th e calyx; b u t i t differs materially in the conformation o f th e lesser lobe o f th e leaf, in the
w hile and delicate tex tu re o f the capsule, in th e irregula rly shaped greenish seeds, and in th e double
spira l f i l a m e n t s i n all these pa rticula rs, and in the shape o f th e stipules, i t so nearly accords
w ith the la tte r ( J . se rpy llifolia), th a t a similarity in the shape o t th e calyx m ig h t n ot unreasonably
be expected. B u t this is fa r from be ing th e c a s e ; for. in J . Mackaii, th e calyx is depressed and has
three a n g le s ; whilst, in J . serpyllifolia, i t is by no means flattened and is furnished with five angles.
This affords a ch aracter th e most decisive in en ab h n g u s to distinguish th e two p la n ts ; which may
be fu rth e r known, even upon a more casual inspection, by th e m uch g re a te r size, deeper, almost
blackish-green, as well as th e closer tex tu re of th e one f J M a c k a ii), when contrasted with the
m in u te r foliage, more cellulose stru c tu re , and ve iy pale gre en o f the o th e r ( J . serpyllifolia).
These peculiarities o t the last mentioned p lan t are dwelt upon by Dr. Wahlenberg, in Ms admirable
R o ra Lappoaica (a copy o f w hich I have b u t la te ly had th e opportunity o f seeing) . u n d e r his
J . cavifoiia; and i t is from his having so done, ra th e r than from his figure (in w hich no fructification
U represented), o r from his specific character, th a t I am induced to believe i t to be th e same as our
J . serpyllifolia; for both will accord equally well with J . Mackaii, as with th a t species. ■■ Colore,"
he says, when speaking of J . cavifoiia, •• lutescente e t hahitu J . complanata: L. convenit, sed
surculi triplo angustióles su n t fere in sequent! ( J . trichomane) specie. Mollis est, e t e retículo
grandiori facta.”