7 . S. E a d u l a Baker.-— Habit of S. natans. Fronds horizontal,
distinctly qietioled, round-obloiig, in. long, in. broad, distinctly
cordate at the base, with 3 0 -4 0 close veins on each side of the
midrib, the whole upper surface rough with contiguous bristle-
tipqied qiaqiillfe, the lower side only clothed with a few minute fine
adpressed hairs. Fruit unknown.
Hab. British Guiana, Parker I Jenman 1114 ! 2213 ! Para, Spruce 508 !
Ilio Janeiro, Ita d d i! Burchell 1580! GUziou 2443 ! Midway between natans
and auriculata.
8. S. MINIMA Baker. — Habit of S. natans. Fronds orbicular,
nearly sessile, -J- in. diam., rounded or slightly cordate at the base,
with about 10 erecto-patent veinlets on each side of the midrib,
each beset with 5 -6 tiifts of minute bristles, the under surface
brownish, and matted with shining pellucid hairs. Fruit imkuowii.
Hab. Santa Catherina, South Brazil, Dr. Fritz Midler 479 !
9. S. AURICUL.WA Aublet Guiau. ii. 909, t. 367. 8. rotmuUfolia
V illd ; Eaddi F il. Bras. t. 1. 8. hispida H. B. K. S. hiloha Eaddi
F il. Bras. 1, t. 1.—Fronds firmer in texture than iu S. natans,
orbicular, deeply cordate at the base, f in. broad, the veinlets very
close, 4 0 -5 0 on each side of the midrib, the upqier surface covered
all oyer with crested papillie, which towards the centre of the leaf
are lengthened out into prolonged pellucid subulate processes of
empty cells, the under surface only thinly pubescent. Conceptacles
4 - 8 111 a cluster, the walls of their cells very flexuose.
_ Var. S. Olfersiana Klotzsch.—Fronds tightly packed, sessile,
i in. diam., with 2 0 -3 0 veinlets on a side.
Hab. Tropical America, from Cuba to South Brazil. Var. Olfersiana.
French &mana PoiteaiC. Sagot 745! South Brazil, Olfers ! Paraguay,
h e re '”’*^ ™ belongs
10. S. S p e u c e i Kuhn in FI. Bras. i. 655, tab. 81, figs. 1 1 -1 3 .—
F iou d s crowded, subsessile, orbicular-cuneate, suberect, cucullate,
} m. broad, glabrous on both sides when mature; veins distinct,
erecto-patent, anastomosing very little. Conceptacles not clustered.
Hab. Amazon Valley, a t Solimoes-gapo, Spruce 1636 (mixed with a small
form of *S. auriculata). ^
V °Y™llata Eoxb. FI. Ind. edit. Clarke 547 ; Wall. Cat.
No. 899.— Fronds sessile, so tightly packed on the stems that they
are nearly or quite erect, with inflexed borders broader ( i - # hi.
broad) than loug, broadly cuneate or cordate at the base the
veiniug laxer aud more flabellate tban iu tbe other species-
veinlets 1 0 -1 2 on each side of the midrib, with 5 -6 hexagonal cells
111 a row between th em ; papillie of upper surface very minute and
close ; under suriace nearly naked. Fruit not seen.
Hab. Tanks of the Plains of India. Swan Eiver, Drummond 352 !
12. S. NYMPHELLULA Dcsv. ill Auii. Liliu. Soo. Par vi 177 _____
ir o iid s suborbicular, cordate, riigoso-pilose above, sericeo-pil’ose
ben ea th ; petiole wedge-shaped.
Hab. West Africa.
1 3 . S. ADNATA Desv. Joe. cit. — Fronds sessile, adnate, broadly
subcuneate, 4 - 5 lines long, densely fasciculato-pilose above, glabrous
beneath.
Hab. Islands of E a st Africa.
E xcluded S p e c ie s .
S. LÆVIGATA Willd. Sp. PI. v. 5 8 7 , proves to be Triancca boi/oten.ns
Karst. ; Eegel Gartenflora, t. 9 8 0 ; in Hijdrocliaridacea..
2 . A z o l l a Lam."
Conceptacles of two kinds, placed in the axils of the leaves of the
same qilaiit, both indéhiscent, one larger, membranous, globose,
containing numerous microspores, which are aggregated in massulæ
whioh are furnished with a membranous cuticle, and are borne on
a branched filiform receptacle ; the other kind smaller, ovoid, containing
a single macrospore, which is crowned by few or many
float-corpuscles, and has a calyptrate cap, whioh is pushed off as
the archegonium developes.—Fugacious floating water-plants with
coqiiously branched stems ; leaves sessile, minute, densely imbricated,
deeqily-lobed, each lobe furnished with a midrib only ; the
stems sending out from the under side into the water copious simple
or feathered solitary or fascicled root-fibres.
Subgenus E u a z o l l a Meyen.— Maorospores crowned with 3 float-
corpuscles. Massulæ of the microspores armed all round with
rigid glochidiate qirocesses. Eoot-fibres solitary Sp. 1 - 3 .
Subgenus E h iz o s p e e m a Meyen.— Macrospores crowned with numerous
float-corpuscles. Massulæ of the microspores armed on
one side with a few weak qirickles without glochidiate tips.
Eoot-fibres fascicled.
Leafy fronds single aud crowded . . . . Sqi. 4.
Leafy fronds placed on a wide-trailing leafless stem Sp. 5 .
1 . A. f i l i c u l o i d e s Lam. Encyc. i. 3 4 8 ; Kuhn in FI. Bras. i.
6 5 8 , tab. 8 2 , figs. 9 - 1 1 . A. maijellanica Willd. A. Arbuscula
D e sv .—Fronds 1 - 2 in. long, coqiiously bipinnate. Leaves green or
often tinted with red-brown, the larger lobe ovate. Maorospore
with 8 float-corpuscles, its cuticle furnished with large discoid
tubercles with deep pits between. Massulæ of microspores furnished
w ith copious rigid processes, without septa, with a glochidiate
tip.
Hab. South America, mainly on the west side, ascending in the Andes to
16,000 ft. The Afiiine forms are dwarf, with nearly orbicular leaf-lobes.
2 . A. r u b r a E . Br. Prodr. 1 6 7 .— Fronds deltoid, J - l in. long,
copiously bipinnate. Leaves of firm texture, red-browii, broad
* See Mettenius in ‘Linna'a,’ xx. 259, figs. 2—3, and ‘ l’iantæ Tinueanæ,’
q>. 51, tab. 25 ; Griffith’s ‘ Icoues,’ tabs. 119—123 ; and Strasburger’s elaborate
monograph, ‘ Ueber Azolla,’ 86 pages 8vo, with 7 plates, Jena, 1873.
I