Delesseria involvens Harv.

• Region

  North America

• Country

  United States of America

• State/Province

  Florida

• County/Municipio

  Monroe Co.

• City/Township

  Key West

• Coordinates

  24.5591, -81.7816

• Coordinate Uncertainty (m)

  3481.57

• Georeferencing Method

  Georeferencing Quick Reference Guide, Version 2012. Located coordinates of geogr. center of Key West. Measured from coord. to farthest extent of the key to find linear extent (3470 m). Used MaNIS Georef. Calculator to find uncertainty (Bounded Area).

• Geodetic Datum

  WGS84

• Distribution

  Map all specimens of this taxon

Delesseria involvens; Harv. Ner. Bor.-Am. 2: 97. pi. 18 G. 1853.

Frond filmy, pale rose-red, linear-lanceolate, attenuate, hav-
ing the apex strongly involute, bordered with oblique bullate undulations
repeatedly proliferous from the articulated midrib with leaflets of simi-
lar form; at length much branched an<£ fastigiate. (Tab. XXII. A.)

Hab. At. Key West, Feb. 1850, W. H. H.., Dr. Blodgett, fv. v.)

The mode of composition of the frond is the same as in the last
species; a primary leaf, by repeated proliferous development, resulting in
a much branched, siibdichotomously or secundly divided, globose, fasti-
giate frond, two or three inches in diameter. Bach individual leaf is
from half an inch to an inch long and about half a line broad, narrow lin-
ear-lanceolate, obtuse at the base, muc attenuate at the extremity, which
is invariably, on very numerous specimens which I have examined, strongly
rolled inwards, and cannot be unrolled without difficulty, immediately rol^
ling up again when released. The margin is quite entire; within it is a
wide border, occupying more than a third part of the breadth of the leaf,
composed of narrow cylindrical cells disposed in obliquely ascending lines
at an angle of about 45° with the midrib; and throughout this borifder the
membrane is raised up in oblong undulations having a common direction with
the lines of cells, and appearing more strongly coloured than the surroun-
ding parts. The portion of the lamina between the border and midrib is £ •
composed of hexagonal cells of which the innermost are largest. The mid-
rib is of the same structure as in D. tenuifolia, but formed of larger
cellules. In old specimens it becomes, when denuded, thickened into the
setaceous stem and branches of the compound frond. Gonceptacles very con- \ ur/
vex, more than hemispherical, borne on the midrib. Tetraspores in small
irregular sori, one at each side of the midrib in the smaller leaves. Co-
lour a pale rosy red. Substance extremely thin and delicate. In drying, £ 9j
it adheres most closely to paper.

Plate XXII. A* Fig. 1. DELESSERIA involvens, the natural size.

Fig. 2. Some leaves, growing proliferously; fig. 3, a leaf, highly mag-
nified to show the structure; fig. 4, tetraspores lying among the si?r-
face cells; all more or less highly magHrfTed'.

^TyorTT

30TAN1CA'-

^ QARD^i

THE NEW YORK BOTANICAL GARDEN

ALGAE EX HERB. W. H. HARVEY
BY EXCHANGE WITH TRINITY COLLEGE,
DUBLIN, 1904

BOTANICAL

Garden

NEW YORK BOTANICAL GARDEN

00900257

BOTANICAL

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