g iv e a connected sketch o f the prominent characters o f the Tasmanian genera. A ll are shm b s or trees,
with th e stems and branches formed on th e same plan as in other D icotyled on ou s plants, but difl'ering
from th e majority o f th ese in th e rarity o f medullary rays, in the h igh ly organized structure o f the tubes
o f the wood, which are studded internally w ith beautifully formed discoid glands ; and they also germinate
as other Dico ty led on s, b e in g exorhizal, b u t sometimes have three or more cotyledons to th e embryo, or, as
some consider, normally two cotyledons, bu t each divided congenitally to th e base into two or more equal
lobes. Their foliage presents many curious forms, and seldom resembles that o f other trees, most so however
in Podocarpus, and lea st so in P h y llo c la d u s aud Frenela.
B o th male and female flowers are deprived o f a perianth ; the males con sist o f sin g le stamens collected
in small cones ; and, from th e uniformity o f the tissue o f all its parts, it would seem that each stamen consists
wholly o f an anther, whose ofteu v ery beautifully constructed and high ly developed connective i s narrowed
below in to a short stipes (not a proper filament), aud dilated above into a broad peltate scale, bearing ce ils
on its margin : the p ollen I have already alluded to ; the grains o f th e curved form in some European
species present a unique development, the p o llen -tu b e em itted on fecundation or iginating in a free cell-
formation vrithin the middle o f the curved part o f each pollen-cell.
The female flowers e ssentially consist o f an ovule , with no in v e stin g ovary, seated upon a scale, called
the ovuliferous scale, which is an open rudimentary ovary ; th ese scales are solitary in P odocarpus, spiked
in D a c iy d ium and Pherosphoera, capitate in Ph y llo c la d u s, two and opposite in D iselm a , whorled in Frenela,
imbricate and forming a cone in Mic rocachry s and A th ro ta x is . I n some genera th ese scales bearing the
o vules are subtended b y a more or le ss free or adnate bract (obviously in the northern P in e s) ; this bract
is seen d istinc tly in some Frenelas and in A th ro ta x is se laginoides to be adnate to th e back o f the ovu liferous
scales, and to form a beak to them ; whereas in A . la x ifo lia and A . selaginoides it appears larger and
broader than th e ovuliferous scale, w'hicli is, as it were, adnate to its inner face. The ovuliferous scales are
])ersisteut in all the Tasmanian genera b u t Pherosphoera, in which the ripe seed and scale togethe r fall
away from th e rachis o f t!\e spike ; iu Podocarpus th e seed, scale, and spike fall away togethe r ; in all the
other genera th e seeds fall away from the ovuliferous scale.
T he ovules are always orthotropous ; they are solitary on each ovuliferous scale in P odocarpus, P h y llocladus,
D a c ryd ium , P herosphoera, and M icrocach rys ; there are two on each scale in D ise lm a ; several in
Fren ela and A th ro ta x is : they are erect, p ointing upwards, in Pherosphoera, D ise lm a , and Fren ela ; inverted,
p o in tin g downwards, in all th e r e st; but in Microcachrys, D a c ryd ium , and P h y llo c la d u s they become partially
or wholly erect as th ey ripen : th ey are free, or inserted by a small base, in all th e genera b u t P o d o carpus,
in which th e outer coat o f th e ovu le (and seed) is adnate th roughout its len g th to the ovuliferous
scale. Tiie ovule con sists o f one or rarely two rather coriaceous coats, and an enclosed nucleus, bu t in
Dacrrydium and P h y llo c la d u s, which have two, th e outer coat covers th e ovule in a very y ou n g state only,
forming a short sheath or incomplete annulus round th e base o f the ovule, at the period o f impregnation
and afterwards; a th ird coat appears in v e stin g th e immature nucleus in some species (as in Mia -o ca ch ry s),
whose exact nature I have n o t determined, b u t it probably b e lon g s to th e n u cleu s. I n some genera
[A th ro ta x is and D ise lm a ) th e oute r coat is contracted a t its apex in to a tu b e ; in others it forms an e x panded,
fimbriated mouth, which, after impregnation, becomes introverted.
N o ac cou n t o f th e structure o f th e n u c leu s o f th e ovule o f the Tasmanian species has hithe rto been
published, b u t it no doubt shares th e peculiarities o f th e b etter-known plants o f this Order, and is assumed
to consist o f a fleshy, conical body, containing an embryo-sac. Afte r th e p ollen has fallen on th e mouth
o f the ovule, it sends a tube, by a very slow process o f growth, in to the substance o f the n u c leu s; the
embryo-sac thereupon becomes filled w ith cellular albumen ; after this, several ce lls (called secondary cmbryo
sacs by some, and corpuscles by others), towards the mieropylar end o f th e cellular con ten ts o f the
embryo-sac, enlarge, aud free cells form within them. Afte r this the p o llen -tu b e again elongates, piercing
the tissu e o f the nucleus, and reaches th e embryo-sac, opposite to a corpuscle; it then pierces th e embryo-
sac itself, and, passing down b etween th e c e ll interposed between the corpuscle and wall o f the sac, finally
reaches th e latter : th is is th e period o f actual fecundation, for th en a c e ll (embryonal vesicle) in th e corpusc
le b egin s to develope an embryo with in itse lf, or sometimes four embryos with in itself, o f whicli only
one usually comes to perfection. This is only a sk e tch o f a very complicated process, whose stages it is
most important that the Tasmanian microscopists should in vestigate in the Conifers o f their island. There
are several accessory points to which attention should be directed, such as the development o f the pollen-
tube itse lf, a complicated proce.«s in some Conifers ; the peculiar development o f th e c ells between th e corpuscles
and walls o f the embryo-sac, which form a sort o f r in g or tu b e over the latter, down which the
p o llen-tube proc eeds; and finally, th e development o f four suspensors, each terminated by an embryo, from
a cell witliin the embryonal vesicle. The above is a résumé o f the discoveries o f Brown, Mirbel, Spach,
and Hoffmeister, to whose labours I m u st refer th e structural botanist who would pursue the in ve stigation .
S u pposing the evolution o f th e embryo to be preceded by th e se complicated processes in Coniferoe,
and accepted as an established fact, o f which there seems to be no doubt, it is n o t easy to compare the proc
ess with th a t o f other P hænogams, in which th e embryo-sac o f the nucleus contains embryonal vesicles,
from whicli sin g le embryos are at once developed ; nor to determine what are the liomologues o f the corp
u sc le s, which latte r inde ed seem to tak e the place o f erabryo-sacs.
One o f the most strik in g phenomena accompanying th is development, is th e great len g th o f time
consumed : in many Conifers th e growth o f tlie pollen-tube takes months, and the r ipening o f the seed two
or more years ; and hence it is that we often find seeds o f Coniferoe to be hard, and fu ll o f well-formed albumen,
but with only rudimentary traces o f the embryo, which is however not hence necessarily abortive, but
only undeveloped.
The following is a clavis o f th e Tasmanian genera ;—
1 . F r e n e l a ,— Frmt la rg e , la te r a l, o f s ix w o o d y v a lv e s , iv itli m a n y e re c t, c om p re s s e d , im b r ic a te s e e d s . Leaves
m in u t e s c a le s , w h o r l e d in th r e e s .
2 . D is e l m a .— Fruit sm a ll, te rm in a l , o f fo u r m in u t e e r e c t sc a le s , w i th tw o e r e c t s e e d s a t th e b a s e o f th e tw o
in n e r s c a le s . Leaves m in u t e , c o ria c e o u s , d e n s e ly im b r ic a t e d o n th e t e tr a g o n o u s b r a n c lile ts .
3 . A t h r o t a x is .— Fi~uit a te rm in a l , g lo b o s e c o n e , w i th a lm o s t w o o d y , p e l ta t e s c a le s , e a c h b e a r in g th r e e to s ix
in v e r t e d se ed s . Leaves d e u s e ly im b r ic a te , c o ria c e o u s .
4 . P h e r o s p h æ r a .— F ru it a sm a ll, te rm in a l s p ik e o f d e c id u o u s s c a le s , e a c h b e a r in g o n e in v e r t e d o v u le , w h ic h ,
a s i t r ip e n s , b e c om e s a n e r e c t, sm a ll s e e d . Leaves m in u te , d e n s e ly im b r ic a t e d a n d a p p re s s e d .
5 . P o d o c a r p u s .— Fruit a s o li ta r y , te rm in a l , in v e rte d , fles liy se e d , c o h e r in g w i th th e sc a le , w h ic h fo rm s a r id g e
o n o n e s id e o f i t ; s e a te d o u a fle s h y p e d u n c le , Leaves s c a tte r e d , fla t, sp r e a d in g , lin e a r .
6. D a c r y d i u m .— F n d t a sm a ll, te rm in a l , c u rv e d s p ik e ( a n im p e r fe c t c o n e ), o f a few sc a le s , e a c h b e a r in g a n in v e r t e d
o v u le . Leaves m in u t e , d e n s e ly im b r ic a t e d a n d a p p re s s e d .
7 . M ic r o c a c h r y s .— Fruit a sm a ll, te rm in a l , o v o id c o n e , o f m a n y , im b r ic a t in g , s h o r t, c o n c a v e s c a le s , e a c li c o n t
a in in g o n e in v e r t e d o v u le , w liic b , a s i t r ip e n s , b e c om e s a s u b e r e c t s e e d . Leaves m in u te , d e n s e ly q u a d r i-
f a r io u s ly im b r ic a t e d a n d a p p re s s e d .
8. P h y l l o c l a d u s .— Fruit a few sc a le s a g g i'e g a te d to g e th e r , e a c h b e a r in g o n e in v e r t e d o v u le , w’h ic h , a s i t
r ip e n s , b e c om e s a n e re c t s e e d . Leaves ( p h y llo d ia ) f la t, c u n e a te o r flab e lla te .
Flores monoici. M a s c . Amenta
Gen. I . E R E N E L A , M ir i.
terminalia, cylindrica. S tam in a numerosa, in a xi sexfariam imbri