Constancea 83, 2002
University and Jepson Herbaria
P.C. Silva Festschrift

Codium elisabethae O.C. Schmidt, Newly Recorded from the Canary Islands

Max E. Chacana
University Herbarium, University of California,
Berkeley, CA 94720-2465, U.S.A.

Codium elisabethae O.C. Schmidt

Codium elisabethae O.C. Schmidt, 1929: 103, fig. 8.
O.C. Schmidt, 1931: 21, fig. 24.


Azores: near Ponta Guarda, southwest of Horta, Ilha do Faial, O.C. Schmidt 645, 9.vii.1928 (B: destroyed during World War II).

Thallus globose or subglobose, hollow, moderately firm, dark green, to 14 cm diam., adherent to substratum by a tuft of rhizoidal attachments. Thallus dissecting out into individual utricles or pairs of utricles, the second utricle being produced directly from the parent utricle; mature utricles of adult thallus subcylindrical to slightly clavate, 265–530 µm diam., (2.5–) 3–5.5 (–6.7) mm long; apices of utricles broadly rounded but acuminate and slightly asymmetrical; utricular wall 2–3 µm thick, to 85 µm thick at apex, where it forms a more or less pronounced obtuse mucro; apical wall finely lamellate. Hair scars relatively abundant on certain utricles, forming band 350–650 µm below apex. Medullary filaments 60–110 (130) µm diam. Gametangia narrowly ellipsoidal to cylindrical, usually tapered anteriorly, 65–130 µm diam., 370–550 µm long, borne usually one (sometimes two, rarely three) per utricle, on pedicel 15–25 µm long, 720–840 µm below apex of utricle..

Known range

Macaronesia (Azores, Madeira, Canary Islands).

Specimens examined
(Voucher specimens housed at herbaria indicated in parentheses. Abbreviations follow Holmgren, Holmgren, and Barnett, 1990) )

AZORES [Açores]. Ilha do Faial: Feteiras, rock pools in sheltered hollow, 25.viii.1952, H.T. Malheiro (BM); near Horta, rocky coast south of harbor, 5–10 m deep, 1–3,, CANCAP Expedition 5, no. 4947 (L); Caldeira Inferno, in open crater of small volcano, shallow and sandy, 4 m deep,, CANCAP Expedition 5, no. 4918 (L). Ilha do Pico: Lajes do Pico, large rock flat in sandy bay with boulders and stones, 1–6 m deep,, CANCAP Expedition 5, no. 5065 (L); 25.viii.1952, H.T. Malheiro (BM, UC); Madalena, 25.viii.1952, H.T. Malheiro (BM). Ilha do São Miguel: Ponta Delgada, rocky shore with tide-pools and large basins,, Lokhorst 5558 (L); Ilheu da Vila, 4 m deep, 31.v.1981, CANCAP Expedition 5, no. 4865; south coast, sheltered bay, 10–20 m deep, 26.v.1981, CANCAP Expedition 5, no. 4508 (L). Ilha de Santa Maria: Setuval (S).

ARQUIPELAGO DA MADEIRA. Ilha do Porto Santo: near Ponta da Calheta, 1–2 m deep, 16.x.1978, CANCAP Expedition 3, no. 791 (L).

ISLAS CANARIAS. El Veril, Islote de Montaña Clara, north of Isla Lanzarote, 5–6 m deep, 31.iii.1983, Prud'homme van Reine 8143 (L).


Codium elisabethae was described by Schmidt from material obtained in the Azores. It was growing on volcanic blocks in clear water at a depth of about 2.5 m. Subsequently, this species was reported from Ilha do Porto Santo in the Madeira Archipelago by Audiffred and Prud'homme van Reine (1985: 28). I have now identified as C. elisabethae a collection from the Canary Islands that had been misidentified as C. bursa (Turner) C. Agardh. Thus, although Codium elisabethae is restricted to Macaronesia, it is widespread within these islands (Fig. 1). Prud'homme van Reine and van den Hoek (1990) listed 21 species of macroalgae believed to be restricted to Macaronesia, but omitted Codium elisabethae, probably unintentionally, as it had previously been cited as a Macaronesian endemic by Prud'homme van Reine (1988). This number of endemics is very small compared to the number of spermatophytes that are endemic to these islands.

Codium elisabethae is remarkable, not in itself, but in conjunction with C. bursa. The thalli of the two species are indistinguishable externally, the distinction being solely anatomical. Whereas in C. bursa (Fig. 2) occasional utricles may have asymmetrical and somewhat thickened apices, typically the apices are only slightly thickened (6–25 µm thick), broadly rounded, and not regularly acuminate as in C. elisabethae (Fig. 3).

It might be expected that two such similar species evolved with the help of geographical isolation, and in fact there is almost no overlap in their known ranges. Codium bursa is abundant in the Mediterranean and extends northward in the eastern Atlantic along the coast of France to southern England. It also occurs on Gran Canaria, Lanzarote, and Fuerteventura islands in the Canary Islands. Codium elisabethae, by contrast, has been reported only from the Azores and Madeira and is now recorded from Lanzarote, the most northerly and easterly of the Canary Islands.

Thus, Lanzarote is the only area where the ranges overlap, but it is not known whether there is any site where the two species grow side-by-side. It would be of great interest to know if the two species are reproducing sexually and, if so, whether they are capable of hybridizing. If hybridization is possible and the two species are sympatric, the question arises as to the nature of the ecological barrier that prevents the two species from merging. The high degree of morphological similarity between the two species suggests that correspondingly small molecular differences would be found between the two genomes, but relevant data are not available. Utricles with pointed apices have been shown to occur in several species representing three different sections of the genus (Silva, 1984: 426, fig. 2). One of these is a crustose species, Codium acuminatum O.C. Schmidt, which was originally described from Madagascar and subsequently reported from Mozambique. It differs morphologically from C. arabicum Kützing, a common Indo-Pacific species, only in having pointed utricles. In the latter species the apices of utricles are slightly rounded and often with alveolate or cribrosely pitted walls. As with the C. bursa-C. elisabethae pair of species, it would be interesting to ascertain the molecular distance between C. acuminatum and C. arabicum.

While studying the marine algae of the Azores, Schmidt found only two thalli of C. elisabethae, both from the type locality and both sterile. Recent collections of this species have been made mainly by the CANCAP Expeditions of the Netherlands Council of Sea Research (1978–1981).

Collecting data on these specimens indicate that C. elisabethae grows subtidally at depths varying from a few centimeters to about 20 m. Gametangia are now described and illustrated for the first time, although Neto (2000: 486) previously reported having found fertile plants in the Azores in October, December, and February.


Audiffred, P.A.J. and Prud'homme van Reine, W.F. 1985.
Marine algae of Ilha do Porto Santo and Deserta Grande (Madeira Archipelago) (CANCAP project Contribution No. 40). Boletim do Museu Municipal do Funchal 37(166): 20–51, 4 figs.
Holmgren, P.K., Holmgren, N.H., and Barnett, L.C. 1990.
Index Herbariorum, I. The Herbaria of the World, 8th ed. New York Botanical Garden, New York. x + 693 pp. [Regnum Vegetabile vol. 120]
Neto, A.I. 2000.
Observations on the biology and ecology of selected macroalgae from the littoral of São Miguel (Azores). Botanica Marina 43: 483–498, 7 figs., I table.
Prud'homme van Reine, W.F. 1988.
Phytogeography of seaweeds of the Azores. Helgoländer Meeresuntersuchungen 42: 165–185, 7 figs., 10 tables.
Prud'homme van Reine, W.F. and van den Hoek, C. 1990.
Biogeography of Macaronesian seaweeds. Courier Forschungsinstitut Senckenberg 129: 55–73, 7 figs., 9 tables.
Schmidt, O.C. 1929.
Beiträge zur Kenntnis der Meeresalgen der Azoren. I. Hedwigia 69: 95–113, 14 figs.
Schmidt, O.C. 1931.
Die marine Vegetation der Azoren in ihren Grundzügen dargestellt. Bibliotheca Botanica 25(102). VIII + 116 pp., 10 pls., 104 figs.
Silva, P.C. 1984.
The role of extrinsic factors in the past and future of green algal systematics. In: Irvine, D.E.G., and John, D.M., (eds.), Systematics of the Green Algae. London etc.: Academic Press. Pp. 419–433, 2 figs.