LEMNA TRISULCA. IVY-LEAVED DUCKWEED.
LEMNA trisulca ; frondibus teneris elliptico-lanceolatis basi caudatis apice serratis, radicibus solitariis
LEMNA trisulca. L im i .S p P l p . 1376. Light/. Scot, to, 537. Huds. Angl.p. 390. With Bot A r r ed a
U J. | 43. Hoffm. derm. ed. 2. m l | § g g § p. 186. Willd. Sp. i H | H B
A P ri*-P- 957. Engl. Bot. t. 926. Decand. Fl. Fr. ed. 3. m l . 9,. p. 589. F l Gall Svn to 119
HYDROPHACE caule filiformi, foliis elliptico-lanceolatis, viviparis. H all Helv. n. 1901.
LENTICULA aquatica trisulca. Raii Syn.p. 129.
LENTICULAMATamosa monorrhiza, foliis oblongis, pcdiculis longioribus donatis. Miohrfi 1Vo». Gcn.p. 16.
Class a nd Ord er . DIANDRIA MONOGYNIA.
[Natural Ord er. AROIDEAE.—NAYADES, Juss. Decand.—HYDROCHARIDIBUS AFFINIS, Brown.']
EN. Char. Perianthium simplex, monophyllum, membranaceum, urceolatum, Fructus: Capsula yel Utriculus mo-
nolocularis.
Gen. Char. Perianth single, monophyllous, membranaceous, urceolate. Fniit, a Capsule or Utricle of l cell.
Root : a solitary filiform pellucid fibre i 1 inch or more long,
calyptrate a t the extremity.
F bohds natant, half an inch or nearly an inch long, green,
pellucid, almost membranaceous, reticulated, elliptical-
or ovato-lanceolate, produced at the base into a slender
tail or petiole, at the extremity more or less serrated,
towards the middle, on each margin, having a longitudinal
cleft which bears either gernmee or flowers.
These gemma are soon developed into new fronds dis-
posed cross-wise, and are many times proliferous.
lower minute, solitary, generally perfect, rarely dioecious.
Pe r ia n t h free, simple, membranaceous, pellucid, reticulated
almost white, urceojate, at length opening longitudinally
on one side., 6
Stamens, when present, two, inserted, upon the receptacle, on
the lower side o f the germen. Filaments longer than
the pistil, white. Anthers yellow, roundish, didy
mous, the cells opening vertically. Pollen yellow, the
granules roundish, muricated.
Pi s t i l : Germen roundish, plane above, keeled beneath.
Style as long as the germen, curved upwards. Stigma
a little spreading, plane.
P e r ic a r p : a Utricle of a roundish reniform shape, depressed
on one side, terminated with the base o f the
style: externally cellular, internally crustaceous.
bEED oblongo-elliptic, placed longitudinally, fixed by its lower
surface.
Albumen abundant, fleshy.
Embryo oblong, contracted near the middle, having the same
direction as the seed.
Radix : fibra solitaria pellucida filiformis uneialis vel ultr
ad apicem calyptrata.
Frondes natantes, semiunciâm vel fere unciam longæ, virides,
pellucidæ, fere membranaceæ, reticulatæ, elliptico- seu
ovato-lanceolatæ, basi in caudam vel petiolum tenuem
productæ, apice magis minusve acute serratæ, medium
versus, in utrumque marginem, rima longitudinali gem-
mifei-a vel florifera. Hæ gemma cito explanatie sunt
in frondes novellas cruciatim dispositas, multoties proliféras.
•Flos minutas, solitarius, pleriimque hermaphroditus, raro dioi-
Perianthium liberum, simplex, membranaceum, pelluci-
dum, reticulatum, fere albidum, urceolatum, demum
bine longitudinaliter ruptum.
Stamina, ubi adsint, duo, ad latus inferius germinis recepta-
cuTp inserta. Filamenta pistillo Iqngiora, alba. Anthem
flayte, rotundatæ, didymæ, loculis verticaliter de-
hiscentibus. Pollen flavum, granulis rotundatis, mu-
ricatis.
Pistillum : Germen subrotundatum, supra planum, subtus
carinatum. Stylus longitudine germinis, sursum cur-
f. vatus. Stigma paululum expansum, planum.
Pericarpium : Utriculus rotundato-reniformis, hinc de-
pressus, basi styli termlnatus : extus cellulosus, intus
crustaceus.
Semen oblongo-ellipticum, longitudinaliter positum, latere in-
feriore affixum.
Albumen copiosum, carnosum.
Embryo oblongus, medium versus paululum constrictus, se-
mmis directione.
^ n r i ^ i t 3- W m * T -
f e i f 1 ndei Flg' 8- Flower destitute of perianth, seen from the upper side. Fig. 9. Female ftower Fi? I B B I
I rmbiyo. Bg. 16. Embryo— all m o n Z k s i modified.' through transversely, show.,., the albumen and
HSBI "■>“ published a dissertation upon the genus Lama, is said by Sir James Smith
j j j ' f w l w to have been the first person who discovered the flowers of this curious though not uncommon” ™
the first to detect t h e W j j W i l a H 1 : l a ‘he Jaal: ° f wb'al1 year Mr. Dawson Turner claimed the honour of being
bon, hood of S o n f Lc"m.a tnm c a >“'Great Britain. They were discovered near Yarmouth ; but from the neigh®
r r ba™. be“ sent t0 S '’"ions times l**wee„ the months of JuneTnd SepteSm-
| So many and striking B I they.bei.ll.§111 different stages of fructification, the accompanying drawing was made. ?
[*“ the other know* ,,hh!ch attead 0,1 tha «P«™» of Lomm, as to distinfuish them at first sight from
■between * stem j B B iM M H w,h o pant mV Eg bc sald 10 conslst of » *ond, since there is no distinction
[»gharbonr for varinn. ll,elad lyldaal3float upon the surface of the water, collected together in great masses, afford-
•nn, water-birds Fr2 ° f ,uqoaUa lnsects, and are the food (as the common English name denotes) of ducks and
« U S U M — B ° f lie ""dur side of the fronds, descend solitary, 1 clustered, simple fibres or “ dicta
««■ W H Ë Ë È m W Ë M Ê È a m bat are terminated 9 a distinct sheath, resembling the calyptra of a
each side near the ^ ^ Y °£., cre se 13 by gemma:, which are produced, generally singly, in marginal clefts seen on
H fcmselvL frem I f r r n d whi ch^Ti 1!'Vl' ' "<•>■ clefts, expand into'perfect plants, lïhich, withiutsepa-
1 Jhestr^r ‘ "“mber “f g«°rations S ’ "S"'" (m tbe present sPccles more Particularly ) bear other fronds,
! ^ produced T i n ^ y " r ? 1-es?.curio“® than the mode o f increase of the fronds which I have now described. These
! a»thers, and C eftf ml ar to that whlc!l bears thegemmæ. A solitary pistil is mostly accomDanied bv two
■ For an artifidafsvstem“ ^ ^ 110118 ,UrCe-kte which bas been usually considered a perianth {Calyx or Coi
'rom recent and H H ystein» ™erelyî sud? a vlevv of the structure might suffice. But Mr. Brown has satisfied himself
^.attention to tbatj . h'S nu* sh°J,ld be Placed among the natural order of Aroidea ; and
|N y diandrous the two eta t lG a we °^,tbe b'u,t> W1R be found to warrant this conclusion. Were this niant
jsively. here} on tJe would be seen to be placed on each side of the germen ; they would not advance progresifotion
at the same nerioH &1G Placed botb on one Slde> and both beneath the germen, and are not seen both in^oer-
1:^ upon as a spadix 4H \u Tbe..1,eceRtacle’ thougli not lengthened out as in most of the Aroideee, is nevertheless to be look-
R S I S » spf a OW or c “ r y diSti0Ct "”ted 40WerS 'Vhich il prod““ s’ *be " b»'u being
pnsiders the ^ ° no§raPb. of the Genus Rosa and a more recent and splendid work on the genus Digitalis
r ( j S S ° J ^ Bfrhr<d r tIfin 0 f (Fructus capsularis) of Humboldt and Kunthf Nova GcJcrk
L T 14 regard to tl,é 2 ? ' ? lch“, d> and as saah 1 have published it in the Flora Scotica.
réfltatelv coP„ “ et H1“ « u“ of seed. 11 ls at the centre of the lower surface ; but there is an appearance of a
P * «remit, x L c H 0d TlUl th J s?ed ltself "'h,cb rans ala“g to one extremity, where is perhaps the true'hilum • at the
Ib >1 th?indk w toh ihcahv Ip doTi o1t rreecoc-lXectu tTo hhafv e seeSn“ md *a°n yb eo tHhdegr efvr u“it. a■ P-T'rëMtrown fleshy mass, which forms a sort of o*percu-
0 D^ltcb^^ a^cavair e ^ a l s o ^ n \ h e * g e n u s ^ ‘ minute cleft ia ^ - U * the forr
' ° tNe». HolUnd* stasnaut wateI’ t*“3 SP3“ 33 “f Lrnna is farfrom uncommon. Mr. Brown has mentioned it as a na-
HO