TAB. XIII.
JAM E S O N IA . Hook, et Grev.
P t e r i s . Cav. Sw. A l l o s o r i Sp. Presl.
Sori paucij parvi, in costam vel venarum prope basin' siti demum confluentes. Sporangia
subsessilia, pilis plurimis articulatis compressis immixta. Semina tria n g u laría.
Indusium continuum membranaceum e margine retroflexo pinnarum, soris
remotum.— Filix australi-Americana, andícola. Frondes lineares, pinnatæ. Rachis
villosa. P in næ numerosa;, arctoe, subimhricatoe, coriaceoe, júniores villosissima;,
brevi-petiolatoe, reniformi-cordatoe, supra convexæ, subtxis concava, costata, venosæ,
venis paucis dichotomis, ramis ad marginem attingentibus.
Jamesonia imbricata.—J . pulchra. Hook, et Grev. le . Fil. t. 178.— Pteris imbricata.
‘^Cav. Hort. R . Matr. 1. Tab.'^ Sw. Fil. p . 102.—Pteris orbiculata. L am . Enc.
b .p . 710.
A single species only is known of this beautiful genus, which, from the nature of the
indusium, without observing the situation of the sporangia, has been referred to Pteris
and Allosorus. The crowded capsules, mixed with copious hairs, do indeed render it
difficult to distinguish their precise mode of insertion, and D r Greville and myself had
been led to consider the sorus to be single near the centre of each pinna; but Mr Bauer’s
dissections, and Mr Smith’s investigations, show that there are several small sori, which
eventually become confluent.
Fig . 1. Portion of the under side of a frond ; magn. 5 diam.—/ 2. Upper side of the s am e ; m. 5
diam.—/ . 3. Under side of a young pinna ; m. 10 diam.—/ . 4. Upper side of the same ; m. 10 diam.
—/ . 5. Under side of a pinna with perfect so ri; m. 10 diam.—/ 6. Upper side of do. m. \0 diam.—
/ 7. Transverse section of the same ; m. 20 diam.—/ . 8. Sporangia in a young state ; m. 100 diam.
— 9. The same in a ripe state ; m.'100 diam.
r i ; ..
1, 1:1