Streblocladia spicata M.Howe

• Region

  South America

• Country

  Peru

• Locality

  Pisco, from drift on the beach

• Coordinates

  -13.7167, -76.2167

• Coordinate Uncertainty (m)

  301

• Distribution

  Map all specimens of this taxon

. TirrT^j t/Uh /jr.- /yp,

Streblocladia spicata sp. nov.

Plants erect, elongate-virgate, wholly ecorticate, 10-20 cm*
high; main axes (sympodial but superficially and illusively mono-
podial) simple or 2 or 3 times subdichotomous near the base or
occasionally above, percurrent, 0.5-0.3 mm. in diameter in basal
parts, 0.35-0.2 mm. towards the apices, subterete or flattened in a
4 : 5 ratio, showing in section 10-12 pericentral siphons and bearing
numerous short suberect or ascending apparently distichous
spicate or spicate-fasciculate branches (secondary sympodial
axes) usually 8 or 9 segments (about 0.8-1.6 mm.) apart, these
falsely lateral branches mostly 2-10 mm. long, those from near
the middle of the main axis sometimes 25 mm. long and thence
diminishing in length towards both apex and base, all (except
the occasional abortive or once dichotomous) bearing apparently
2-4 ranks of acuminate or spiniform, often recurved and occa-
sionally subfalcate-recurved ultimate ramuli 0.25-0.65 mm. long,
these, in the more vigorous, more or less intermingled with very
short sympodial axes of the third order; ultimate ramuli showing
usually 6-9 pericentral siphons, the number decreasing rather
abruptly at the commonly spiniform, often indurated and brown-
ish, 1- or 2-celled monosiphonous apex; segments in the upper
parts 2.5-4 times, in basal parts 3.5-5 times, as broad as long,
the short pericentral siphons often showing a slight spiral twist
and in the older parts often becoming somewhat irregular in size
and position.; reproductive parts wanting. [Plate 56; plate 57,
figures 1-8.]

Attached to a shell and washed ashore at Pisco, Coker 465 p.p.,
July 7, 1908.

The present species is perhaps mostly nearly allied to Streblo-
cladia fasciculif era (Kiitz.) Falkenb. from the Cape of Good Hope
(not Polysiphonia fasciculifera Kiitz. Tab. Phyc. 13: pi. 61. f. a-d),
but evidently is amply distinct in the spiciform rather than
fasciculate grouping of its secondary and tertiary axes, in the
shorter ultimate ramuli (^->2 as long), which are mostly recurved
at the apex (forcipate-incurved in only the very youngest parts),
and in having 10-12 pericentral siphons in the main axes instead
of 14-18. In habit S. spicata is a little suggestive of strict slender
conditions of Acanthophora spicifera (Vahl) Borg., but is always
much more slender and delicate.

“ Poly siphonia Zimmermanni Suhr mscr.,” attributed to
Callao, and cited by J. Agardh* in the synonymy of Poly siphonia
thyrsigera and by De-Tonif in the synonymy of Bryocladia tliyrsig-
era, possibly belongs here, but we have no means at hand for
proving it. The number of pericentral siphons of the La Guayran
Poly siphonia thyrsigera J. Ag. is essentially the same as in Streblo-
cladia spicata and Kiitzing’s figures (Tab. Phyc. 14: pi. jj. f. e,f.)
show branches of somewhat similar form, but both descriptions
and figures indicate that Bryocladia thyrsigera is a plant of mono-
podial axes and accordingly of very different habit from that of
Streblocladia spicata:

Plate 57, figures 1-8. Streblocladia spicata

1.	A typical pinna.

2.	Apical portion of main axis.

3.	One of the lower pinnae.

4.	Cross sections of main axes.

.5. Surface view of pericentral siphons in lower part of main axis.

6.	Pericentral siphons of the usual mature form in surface view.

7,	8. Apices of ultimate ramuli.

The figures are all drawn from the type material (Pisco, Coker 465 p.p.). Figures
1-3 are enlarged 28 diameters; 4-6, 40 diameters; 7 and 8, 245 diameters.

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Mem. Torrey Club

Volume 15, Plate 57

i - 8. Streblocladia spicata M. A. Howe

Plate 56. Streblocladia spicata
A photograph of the type specimen (dried), natural size.

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00922240