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D IC K SO N IA . L 'H é rit.
D e n n s t a e d t j a . Bernh.
Sort globosi, parvi. Indusium scariosum, valvulis dissimilibus demum p a tentibus,
verum semilunare, accessorium e dente frondis reflexo efformatum, operculiforme.
Beceptaculum punctiforme, minimum. Sporangia longe pedicellata Filices
pleræque inlratropicee. Rhizoma repens. F ro n d es sparsoe, herbaceæ, pinnato-
decompositoe et supradecompositoe, tenues, plerumque amploe. Venæ pinnatæ, tenues,
pinnatim ramosæ, venulisque sublus prominulæ, infima superiore subinde et inferiore
apice sorifera supra puncto impresso sorum indicante insignita P r .
Dicksonia tenera, Presl— ( T a b . L X I . A .)—D . adiantoides. L in k .
I have chosen the Dicksonia tenera, (P r.) as illustrative of Presl’s ideas of tills Genus,
because I consider tlie specimen in my Herbarium (from tlie Berlin collection,) authority
for that plant. But I cannot see that the indusinm is so decidedly and unequally 2-valved
as Presl’s character and figure express it to be. It appears, indeed, to be formed of a
dilated (at length membranaceous,) portion or tooth of the frond, which unites with a
scale arising from the apex of a nerve on the underside of the pinnule : at first they form
a nearly globose entire indusium, which soon bursts at the top, sometimes with a transverse
cleft, and then the indusinm seems 2-valved; sometimes with an irregular circular opening,
and then the indnsium appears pateræform, and in no way different from the following
genus, Patania. I may observe, in specimens in ray Herbarium of D. Martiana, (Kl.), and
of what I take to be D. dissecta and D. adiantoides, the indusium is more constantly 2-
valved tlian in the present species, and scarcely differs from that of Culcita (see T a b . LX.)
hut in being of a more membranaceous texture. The name of Dicksonia surely, however,
ought to be preserved to the original D . arborescens (Balantium, Kaulf., T ab. nostr. X X .)
Tlie species included in Dicksonia of Presl, are D. puhescens, (Schk.), D. apiifotia, (Sw.),
D. tenera, (P r.), D. adiantoides, (Humb.), D. angustidens, (P r.), D. cicutaria, (Sw.)
Pig. 1. Under, and f . 2. Upper porlion of fertile frond of D. tenera, (P r.) ; / 3 . Sorus ; f . 4. Spor.
aiigium ; f . o. Sporules :—magnijied.
TA B . L X I . B.
P A T A N IA . Presl.
D i c k s o n i i e sp. Willd. Kunze. D a v a l l iæ sp. Presl.
Sori globos!, subm.irginales. Indusium ten u ite r coriaceum, pateræforme, intege rri-
mum, basin tantum sori involucrans, persistons, p a rte superiori e dente frondis
a lterato constituta. Beceptaculum tuberculiforme, globosum, minutum. Sporangia
longe pedicellata.— Rhizoma repens. Frondes sparsoe, coriaceoe, pinnatim
composite et supradecompositoe, amploe. Venæ pinnatæ, tenues, subtus parum p ro minulæ,
fu rca tæ, inferiores bi-trifurcatoe, venulis sterilibus apice libero acutis, infimis
superioribus apice punctiformi-incrassato soriferis Pr.
P a ta n ia erosa, Math. Herb. P e ru v .n . 97 4 ( T a b . L X I . B .)
To this Genus the author assigns only three species, natives of Peru, P. obtusifolia,
(Dicksonia, Willd.), P. erosa, (Dicksonia, Kze.), and P . condnna, (P r.), but to wiiich I
think several of Presl’s Dicksoniæ may without violence be referred, since their only character
lies in the entire (not 2-vaIved,) and pateræform indusium.
Fig. I. Under portion of fertile p in n u le ; / . 2. Indusium; / . 3. Portion and receptacle with
sporangia ; f . 4. Sporangium ; f . Sporules ■.— magnified.