Botryocladia botryoides exhibits as its most relevant attributes arborescent solid axes bearing near-spherical determinate lateral vesicles, vesicle walls consisting of four (to six) cell layers, outer cortical cells loosely arranged forming a near-continuous surface layer, one to four secretory cells borne both on unmodified and modified stellate medullary cells, spermatangia cut off from closely packed palisade-like spermatangial mother cells, cystocarps incompletely immersed in the vesicle, and tetrasporangia derived from an inner intercalary cortical cell remaining immersed in the subsurface cortical layer.

Plants rose red to honey pink, erect, up to 11 cm in length, with irregular pseudodichotomous branching. Main axis and branches terete, 9-2.5 mm in diam., of solid construction, composed of small pigmented, round to oval, cortical cells (5 µm diam.) that gradually increase in size thallus inward; medullary cells larger, hyaline, ovoid, up to 50 µm. Axis and branches bearing pyriform vesicles ( Fig. B) 3–7 mm long. x 3-4.5 mm diam., filled with viscous mucilage. Vesicle walls 2-(3)-4 cells wide and 66-(100)-135 µm thick. Cortex of vesicle complete, uni-bistratose, pigmented, composed of round to ovoid cells, 3-6 µm in diameter, distal to larger medullary cells. Innermost medulla composed of 1-(2) layers of hyaline cells, with innermost layer polygonal, 77-(100-132)-180 µm wide, outer medulla of intermediate-sized cells. Some unmodified medullary cells cutting off thallus inward spherical gland cells 17-(20)-25 µm diam. borne singly or rarely paired.

Afonso-Carrillo, J., Rodriguez-Prieto, C., Boisset, F., Sobrino, C., Tittley, I. & Neto, A.I. (2006). Botryocladia chiajeana and Botryocladia macaronesica sp. nov. (Rhodymeniaceae, Rhodophyta) from the Mediterranean and the eastern Atlantic, with a discussion on the closely related genus Irvinea. Phycologia 45: 277-292.

Braune, W. (2008). Meeresalgen. Ein Farbbildführer zu den verbreiteten benthischen Grün- Braun- und Rotalgen der Weltmeere. pp. [1]-596, 266 pls. Ruggell: A.R.G. Gantner Verlag.

Wilkes, R.J., McIvor, L. & Guiry, M.D. (2006). Vegetative morphology and rbcL phylogeny of some members of the genera Botryocladia and Irvinea (Rhodymeniaceae, Rhodophyta). Phycologia 45: 481-494.

Basionym: Fucus botryoides Wulfen

Type locality: Adriatic Sea (Silva, Basson & Moe 1996: 352).

Notes: Type locality: Trieste, Adriatic Sea (western Mediterranean) (Afonso-Carrillo & Sobrino 2003).