tutin. 1940. the algae

XI. THE ALGAE

BY T. G. TUTIN, M.A., Assistant Lecturer in Botany, Victoria University, Manchester

(Plate VI. Three text-figures)

Read 9 May 1940

CONTENTS PAGE

I. Chemical factors . . 191 11. Phytoplankton . . 192

111. Algae of ponds . . 195

V. Summary . . 202 IV. Systematic list of algae . . 196

VI. References . . 202

I. CHEMICAL FACTORS

FOR the algal flora the concentrations of dissolved salts, particularly nitrates and phosphates, are of great importance, but unfortunately there is not much information about these in the case of Titicaca. The concentrations of chlorides in the various lakes, which may be taken as a general indication of the relative salt-contents, have already been given (Tutin 1940, p. 180) and it will be seen from this table that, except in the case of Lagunilla Saracocha and Lake Langui, this is very high for fresh water. The estimation of nitrates in Titicaca was difficult owing to this high concentration of other salts, but phosphates were present in about the quantities usually found in fairly rich temperate lakes. Silica, which is of importance to diatoms, was always abundant. The concentration of calcium was high enough not to limit algal growth, as will be seen from Table I.

TABLE I LAKE Ca (mg./l.)

Lagunilla Lagunilla 27.0 Lago Pequeiio 63.4 Lago Grande 68-8 Lagunilla Saracocha 95-0

It is interesting to note that calcium is much more abundant in Lagunilla Saracocha than in Lagunilla Lagunilla, though the former has only 68 p.p.m. C1, while the latter has 236. It will also be seen that calcium is somewhat lower in the Lago Pequeiio than in the Lago Grande, while the reverse is true of the chlorides. The most probable explanation of this seems to be that the lime-incrusted Charophyta, which occupy a large area in the Lago Pequeiio but are comparatively scarce in the Lago Grande, produce this difference by removing calcium in appreciable quantities from the relatively small volume of water in the Lago Pequefio.

Since our visit to Lake Titicaca was confined to the winter, during which the climate shows little variation, large changes in the plankton or in the dissolved salts were not to be expected, and such changes did not in fact occur.

24-2

192 PERCY SLADEN TRUST EXPEDITION

11. PHYTOPLANKTON

Plankton collections were made at intervals throughout our stay in widely separated parts of the lake with the ordinary silk tow-net of 71 meshes per cm., which was towed slowly through the water near the surface. These were supplemented by collections made with the Harvey net (Harvey 1934), which was hauled vertically for 10m. and then closed, so that collections could be made over a definite depth range to discover if any horizontal stratification of the plankton existed. The volume of water filtered through this net in each haul was recorded and so an estimate of the density of the population could be made by counting the numbers of organisms in a known proportion of the catch.

Although Titicaca has a high salt-content the plankton is not of the kind usually associated with such waters. The thirty collections made in different parts of the lake down to a depth of 50 m. show an unusual degree of uniformity, in marked contrast to the variations from place to place generally found even in much smaller bodies of water. It will be noticed that in this respect the plankton resembles the rooted vegetation, and it is possible that the Uniformity in this case also may be due to the rather limited number of species which occur.

The following 15 species were found in the plankton of the Lago Grande, the first five being present in all, or nearly all, of the collections:

Ankistrodesmus longissimus (Lemmerm.) Wille. Botryococcus Braunii Kutz. Dictyosphaerium Ehrenbergianum Naeg. Staurastrum paradoxum Meyen. Ulotlirix subtilissima Rabenh. Coelastrzirn microporum Naeg. Uncommon, usu-

ally between 10 and 50 m. Xtephanodiscus Astraea (Ehrenb.) Grun. Rare. Lagerheirnia sp. Rare, usually between 10 and

Mougeotia sp. Uncommon. 30 ni.

Nodularia Harveyana Thur. Fairly frequent. Oocystis gigas Archer var. Borgei Lemmerm.

Never common but fairly constant. Possibly rather more abundant in July than earlier.

Pediastrum Boryanum (Turpin) Menegh. Un- common.

P. cf. Kawraiskyi Schmidle In three collections. Peridinium sp. In most collections, especially the

Sphaerocystis Sclrroeteri Chodat. Sporadic. deeper ones.

In examining the quantitative collections it was found that Botryococcus occurred in masses varying so much in area and thickness that i t was impossible to make anything approaching an accurate estimate of its abundance, and this species was consequently left out of the counts. The same difficulty was experienced with the other colonial species but to a much lesser extent, as the variation in size of the colonies was not great, the large species usually having only about four times the number of cells found in the smaller. In the counts each colony was recorded as one individual regardless of its size. The results of these counts are given in Table 11, which shows the numbers per litre at different depths on three occasions. Only the more abundant species were counted and the figures are the average for several counts from each collection.

This table proves that the numbers of the common plankton algae do not show any significant variations between the surface and 50 m., though the less abundant organisms appear to have a less uniform distribution, as has been indicated in the list above. The small number of collections and the short period over which they were taken make i t

TUTIN-ALGAE 193

impossible to draw any definite conclusions about this matter; indeed the evidence is mainly negative. The average numbers per litre for all the organisms (excluding Botryo- coccus), and for Dictyosphaerium separately, are also given in Table I1 from which it will be seen that the plankton is always sparse compared with that found in Lake Mendota, for example, where filaments of the diatom Melosira alone may reach a figure of nearly 30,000 per litre (Birge and Juday 1922). No collections were made of the nannoplankton, which in many lakes has a density of several million individuals per litre.

TABLE I1 Depth in motros : . . . ... Dictyosphaerium EhrerLbergiawum

Staurastrum paradoxurn

Ankistrodesmus longissimus

Peridinium sp.

0-10 10-20 1930 840 1070 1300

170 130 140 80

170 120 180 190

260 300 60 130

- -

- -

- -

Ulothrix szi bt ilissima 90 90 60 60

AVERAGE TOTALS

Dictyosphaerium Other species

1500 840 2050 1890

20-30 1370 1470 1960

190 100 270 170 170 50

140 50 90

100 60

110

1600 2120

30-40 1350 1290 1300 230 80

300 100 90 70

190 80

110 60 80

130

1140 1610

40-50 1130

1950 120

390 60

100 160

140 40

150

-

-

-

-

-

1540 2130

Date 5 July

19 June 22 July 6 Ju ly

19 Julie 22 July 5 Ju ly

19 June 22 Ju ly 5 July

19 June 22 July

5 July 19 June 22 July

In the single collection from the Lago Pequefio all the commonest species found in the Lago Grande occurred, with the rather surprising exception of Dictyosphaerium. The complete list of this collection comprises seven species, among which only the Oedogonium was not found in the Lago Grande:

Ankistrodesmus longissimus (Lemmerm.) Wille. Botryococcus Braunii Kutz. Oedogonium sp. Staurastrum paradoxurn Meyen. Peridinium sp. Ulothrix subtilissima Rabenh.

Mougeotia sp.

In the other lakes visited no quantitative collections were made and, with the exception of Lake Poop6 where two collections were taken, only one collection was made in each lake. The results of these rather scanty collections are however of sufficient interest to be listed in full as they indicate a great difference in the composition of the phytoplankton in the different lakes, in marked contrast to the uniformity within Titicaca it self.

LAKE POOP6

Botryococcus Brami i Kutz. Glenodinium sp.

Rliabdoderma salina Tutin. Lyngbya aestuarii (Mert.) Liebmann.

All the species were present in both collections.


LAGUNILLA LAGUNILLA

Ankistrodesmus longissimus (Lemmerm.) Wille. Marssoniella andicola Tutin. Abundant. Botryococcus Braunii Kiitz. Uncommon. Oscillatoria sp. Chroococcus limneticua Lemm. var. distans Peridinium sp.

Coelastrum microporum Naeg. Abundant. G.M.Sm. Xtaurastrum paradoxum Meyen.

LAGUNILLA SARACOCHA

Botryococcus Braunii Kiitz. Peridinium sp.

Sphaerocystis Schroeteri Chodat.

LAKE LANGUI

Eudorina elegans Ehrenb.

These lists show a t once the very wide tolerance of Botryococcus to variations in the concentration of salts, as it is the only species which occurs both in Lake Poop6 with 5000 parts of chloride per million and in Lagunilla Saracocha with only 68 p.p.m.

In general a greater number of species is found in lakes where the concentration of dissolved salts is low, than in those where it is high, though the density of the population is usually much higher in the latter than in the former. The plankton collections from Lagunilla Lagunilla, Lagunilla Saracocha and Lake Langui are comparable since only a single collection was made in each and they show that in these lakes the number of species decreases with decreasing salinity (Table 111).

TABLE I11

Lagunilla Lagunilla 236 8 Lagunilla Saracocha 68 3 Lake Langui 37 1

In Titicaca with a slightly higher salinity than Lagunilla Lagunilla the average number of species in a collection is 8 to 9. Lake Poop6 is excluded from this comparison because its salinity is far in excess of that of normal fresh waters. With the exception of Lake Titicaca no figures for the density of the population were obtained, but since the collections from the other lakes showed no obviously great increase in the abundance of the organisms it may be assumed that they also have rather sparse populations. Since all the collections were made a t one season in a single year any generalizations made about them must be regarded with caution.

The distribution of the various types of algae in relation to the concentration of dissolved salts in these Andean lakes differs considerably from that found by Pearsall (1921) to occur in the English Lakes. He found that as the amounts of dissolved salts, silt and macrophytic vegetation increased the plankton was dominated by. the following algae in turn : Desmids with Sphaerocystis Schroeteri; Desmids and Diatoms (especially Ttcbellaria) ; Diatoms with Eudorina and Ceratium ; and finally Asterionella and Cyano- phyceae. The Andean lakes are found among much softer rocks than occur in the English Lake District and consequently all show a considerable amount of silting. The macrophytic vegetation does not vary much in composition or quantity from one to another, but the amounts of dissolved salts, which are generally thought to be of prime importance to algae, show a large variation. The sequence of plankton algae, from the

LAKE C1 p.p.m. No. of species

TUTIN-ALGAE 195

lowest to the highest salt concentrations, in these lakes is as follows: Eudorinu; Sphaero- cystis Schroeteri and Peyidiniurn ; Coelustrurn, Cyanophyceae and a Desmid ; Chloro- coccales, Botryococcus, Sphaerocystis, a Desmid and, though rarely, a centric Diatom. The most striking features here are the nearly complete absence of Diatoms, which are usually dominant in lakes rich in salts, and the fact that the Desmid only occurs in the richer lakes. The abundance of Cyanophyceae in Lagunilla Lagunilla and their complete absence from Titicaca is also very remarkable. -4 theory to account for this unusual distribution does not seem possible as the avail-

able data are too scanty and a longer period of observation would be necessary to establish fully the character and seasonal variation of the plankton of these lakes. The facts indicate that the correlation between the concentration of mineral salts and the type of plankton does not hold in all cases and suggest that the investigation of other factors would be desirable. Harvey (1939) has shown that certain other substances are necessary for the growth of one species of marine plankton diatom, and these might be found to play an important part in the life of freshwater plankton algae. The information available, though inadequate as the basis for a definite statement, may be taken as indicating that the correlation between the type of plankton and the usually investigated dissolved substances is, a t least in part, fortuitous.*

111. ALGAE OF PONDS

A number of collections of algae were made from ponds and ditches on the Capachica peninsula, and a few in other localities. Many of these ponds are artificial and used for watering cattle, and a number of them become completely dry in winter. Like all ponds they are very diverse in their physical and chemical characteristics and are inhabited by a considerable variety of species whose distribution is undoubtedly in part a matter of chance, though it may in some cases bear a relationship to the conditions in the particular pond. The temperature varies rapidly in the course of the day and the range is large, while in those ponds which dry up there is a drastic change of conditions from one season to another. In all the smaller bodies of fresh water with the onset of the dry season the concentration of salts and the p H increase steadily and may reach a very high figure. There was insufficient time to make a proper study of the ponds, which present a much more complex problem than the lakes, but a list of the algae found in them is given below, together with the algae found in the lakes.

IV. SYSTEMATIC LIST OF ALGAE

1. VOLVOCALES CHLAMYDOMONADINEAE. Cldamydomonas spp. Ponds, Capachica peninsula. Obtained on wetting dried mud. Carteria sp. As above. Phacotus sp. As above.

* The use of the terms “oligotrophic” and “eutrophic” has been deliberately avoided in the foregoing dis- cussion as these words have been used in very diverse ways by hydrographers, algologists and zoologists. It is hoped to discuss the use of these terms and questions connected with the relations between phytoplankton and nutrient salts in more dotail in a later paper.


Pandorina morum (Mull.) Bory. A224, A225 Capachica stream. Small colonies c. 30p in diameter. A214 pond near Chapa Hacienda, Capachica peninsula. Obtained on wetting dried mud from ponds.

Gonium pectorale Mull. Obtained on wetting dried mud from ponds. G . sociale (Duj.) Warm. Obtained on wetting dried mud from shore of Pun0 Bay. Very abundant. Eudorina elegam Ehrenb. P.F.H. 215 Lake Langui. Sole constituent of the plankton. Volvox aureus Ehrenb.* A240 stream in Choccocoya Bay; A260 pond, Capachica peninsula.

TETRASPORINEAE. Gloeocystis ampla Kutz. Dried mud collected near high water mark in Puno Bay. Palmodictyon varium (Naeg.) Lemmerm. A200, A205 ponds, Capachica peninsula. Sphaerocystis Schroeteri Chodat. Spring near Lagunilla Lagunilla, alt. 4300 m. ; P.F.H. 232 plankton,

Lagunilla Saracocha; A200, A202, A2 1 1 ponds, Capachica peninsula; dried mud from Capachica stream and ponds ; P.F.H. 84, A216, A229, A233, A236, A243, A244 plankton, Lake Titicaca. Sporadic.

2. CHLOROCOCCALES

Tetraedron trigonum (Naeg.) Hansg. Obtained on wetting mud from shore of Pun0 Bay. Radiococcucl sp. Obtained on wetting mud from a pond, Capachica peninsula. Colonies of four cells,

more loosely aggregated in groups of four in a mucilage envelope c. 5 p br. with distinct radial striations. Cells 7 p 1.) 4 p br., chloroplast shallow cup-shaped, pyrenoid solitary. The Peruvian specimens differ from the two species of this genus in having the cells distinctly elongated, not round, and the mucilage envelope rather narrow, but nevertheless seem to belong here as the structure of the chloroplast and mucilage envelope is that characteristic of the genus.

Oocystis g igas Archer var. Borgei Lemmerm. P.F.H. 284, A234, A236, A237, A239, A246-250, A266, A268 plankton, Lake Titicaca. Commoner in July than earlier.

Lagerheimia sp. A238, A247, A249, A266 plankton, Lake Titicaca. Collected with the Harvey net between 10 and 30 m. ; always rare.

Actinastrum Hantzschii Lagerh. Obtained on wetting mud from a pond, Capachica peninsula. Ankistrodesmucl longissirnus (Lemmerm.) Wille. P.F.H. 225 plankton, Lagunilla Lagunilla ; P.F.H.

164 plankton, Lake Titicaca (Lago Pequefio); P.F.H. 84, P.F.H. 284, A216, A219, A227, A229, A232-234, A236-239, A243, A244,8246-251, A254, A255, A266-268 plankton, Lake Titicaca. Occurred in every plankton collection made in this lake.

A. falcatucl (Corda) Ralfs. Obtained on wetting mud from the shore of Puno Bay. In groups of 2-10 individuals, 2 p br.

Dictyosphaerium Ehrenbergianum Naeg. In all plankton collections from Lake Titicaca as above. Absent from Lagunilla Lagunilla and Lago Pequeiio. A 235 Capachica stream ; obtained on wetting mud from the shore of Pun0 Bay.

Pediastrum bidentulatum Al. Braun. A 205 pond, Capachica peninsula. P. Boryanum (Turpin) Menegh. A233, A248, A266, A267 plankton, Lake Titicaca. Occurring down

to 40m. , but not common. Obtained on wetting mud from Capachica stream and shore of Pun0 Bay.

P. Boryanum (Turpin) Menegh. var. granulatum Kutz. Obtained on wetting mud from ponds, Capachica peninsula.

P. cf. Kawraiskyi Schmidle. A216 plankton, Lake Titicaca. Marginal cells of coenobium c. 7p 1. and 6 p br. with two processes 2 p 1. lying over each other. Inner cells more or less rectangular, c. 6 p diam. with triangular spaces between them with sides 3 - 3 . 5 ~ 1. Cell walls smooth, processes smooth and blunt. P.F.H. 84, A266 plankton, Lake Titicaca. Similar to A216 but without perforations in the coenobium.

Pediastrum sp. A241 small lake in crater, San Antonio de Esquilache. Coenobium c. 75p diam., outer cells nearly square 9 p diam., with a rather broad indentation 4-5p deep, and two processes 6p 1. Inner cells c. lop br., 4-5p 1. with a broad, shallow rather asymmetrical indentation on their outer side.

* I have to thank Dr M. A. Pocock for identifying the specimans of Volvox.

TUTIN-ALGAE 197

Hydrodictyon patemeforme Pocock. A 205 pond, Capachica peninsula. Obtained abundantly on wetting mud from the same pond. This species, when kept in the laboratory under as nearly as possible the same conditions as H . reticulatum, produced only gametes, while the latter formed zoospores freely and so reproduced its characteristic cylindrical nets. The circular flat coenobia of the former grew rapidly, forming large tangled nets of coarse dirty green coenocytes up to 1.5 cm. long (PI. VI). The specimens agree perfectly with l)r Pocock’s description and plates.

Crucigenia andicola sp.nov. (Fig. 1 ) . A 200 pond, Capachica peninsula.

al3 Coenobium 8 p longum, 6 p latum, quadricellulatum cellulis saepissime magni- tudine aliquanto inaequalibus, c. 3p longis, 2p latis. Coenobia quaterna saepe in colonias laxe juncta e t coloniae illae quaternae in colonias majores, usque ad 4 2 p longas, 27 p latas, laxissime junctae.

somewhat unequal in size. Coenobia often loosely united in groups of four, and 1600). these again very loosely united in groups of four, the large colonies reaching 4 2 p 1. and 27p br.

Fig. 1. Cruci- Coenobium 8 p 1. and 6 p br. of 4 cells c. 3p 1. and 2 p br., the cells being usually genia andicoza

spnov. ( x c .

Scenedesmus denticulatus Lagerheim. A 225, A 226 Capachica stream. S. incrassatulus Bohlin. Obtained on wetting mud from Capachica stream. S. obliquus (Turpin) Kutz. A225, A235 Capachica stream; obtained on wetting mud from Puno Bay. S. quadricauda (Turpin) BrQb. Obtained on wetting mud from Laguna Tejane (Titicaca) and from

shore of Pun0 Ray. Coelastrum microporum Naeg. P.F.H. 225 plankton, Lagunilla Lagunilla, abundant; A254, A237,

A248, A249, A268 plankton, Lake Titicaca, rare; collections, except the first two, made with the Harvey net between 10 and 50 m.

Cliaracium falcatum Schroeder. Obtained on wetting mud from shore of Puno Bay. C. Sieboldii A. Braun. A226 Capachica stream, common; obtained on wetting mud from poad,

Capachica peninsula.

3. ULOTHRICALES

Ulotluix swhtilissima Rabenli. P.F.H. 164 plankton, Lake Titicaca (Lago Pequeiio). All plankton collections from Lake Titicaca (Lago Grande) except P.F.H. 284. (See under Ankistrodesinus longissimus. )

U . variabilis Kutz. Obtained on wetting mud from pond, Capachica peninsula. Monostroma sp. A228 fast-flowing stream near Puno. Sphaeroplea annulina (Roth.) C. A. Agardh. Obtained on wetting mud from Capachica stream.

4. CLADOPHORALES

Cladopliora glomeratn (I,.) Kiitz. ~ i ~ i p l . Brand. A 222-224 Capachica stream, on stones; A257, A 25!). A261 Taman, common on boulders; A256 Rio Urubamba a t Quillobamba (1100 m.); A207 ? young plants, Taman.

C. crispata (Roth.) Kutz. ampl. Brand. A258 Taman, on boulders; in deeper water than the last. C. cf. fracta Kiitz. ampl. Brand. A 256 Rio Urubamba at Quillobamba.

5. CHAETOPHORALES

Stigeoclonium sp.A. A220, A 221 Capachica stream. Little branched, branches short and thorn-like, occasionally long, alternate. Cells 15p br., about three times as long, chloroplasts small. Forming zoospores. Also obtained on wetting mud.

Stigeoclonium sp.B. Obtained on wetting mud from ponds, Capachica peninsula. Creeping system extensive, cells rather variable in size, usually rounded, distal ones elongated, 2-3 times as long as broad. Chloroplasts large. Erect shoots often arising in groups of 2 or 3, cells of main axis c. 9 p br., 15-3Op l., constricted at end walls. Chloroplast a parietal band round the middle of the cell. Branches mostly alternate, ending in a very long hyaline hair. Cells from which branches arise 10-12p l., 9-lop br. Cells of branches c. 25p l., 6 p br. Branches usually about 150p 1. with hairs about 8OOp 1. In some plants the constrictions between the cells of the main filament were

TRANS. LINK. S O L ( 3 ) , VOL. I , I?. 2. 25


very marked, and the branching dichotomous, the cells from which the branches arose being nearly round and about 8 p in diameter.

The taxonomy of Stigeoclonium is in a confused state and no specific determination of the above forms seems possible a t present.

Aphanochaete plychaete (Hansg.) Fritsch. A 2 12 pond, Capachica peninsula. A . repens A. Braun. Obtained on wetting mud from Capachica stream. Gliaetopeltis orbicularis Berthold. A262 common on microscope slides left for three weeks in 0.5 m.

on Zannichellia in moderate shelter, in 1.5 ni. among totora and in 0-5 m. on a bare sandy bottom in Taman.

6. OEDOGONIALES

Bulbocliaete sp. Obtained on wetting mud from a pond, Capachica peninsula. Sterile. Oedocladium sp. A 220 Capachica stream. Sterile. Oedogonium andinum sp.nov. (Fig. 2). Obtained on wetting mud from the shore of Puno Bay and from

a pond, Capachica peninsula. Nannandrum, gynandrosporum. Filamentum 10-15p dianietro,

cellulis 130-14Op longis; cellula basalis plus minusve inflata. An- drosporangia 12p lata, 16p longa. Nannandria stipite 27 p longo, 9 p lato, piriforme ; antheridium unicellulatum 9 p longum, 9 p latum. Oogonia solitaria, 28-42 pdiametro, 40-55 p longa, poro lato superiore. Oospora matura castanea, levis, oblonga vel sphaerica, oogonium totum apice porum versus except0 complens, 30-46p longa, 25-4Op lata.

Nanandrous, gynandrosporous. Diam. of filament 10-1 5 p, cells 130-140p I., basal cell usudly somewhat swollen. Andro- sporangia 12p br., 16p 1. Stalk cell of dwarf males 27p l., 9 p br., piriform; antheridium 1-celled, 9 p l., 9 p br. Oogonia solitary, 28- 42p diam., 40-55p l., opening by a wide superior pore; ripe oospore chestnut brown, smooth, oblong or spherical, completely filling the oogonium except for the top near the pore, 30-46p l., 25-4Op br. Differs from 0. Hoersliolmiense Hallas, which i t most nearly resembles, in the nearly spherical oospore, the solitary antheridium and the smaller dwarf male.

0. armigerum Hirn. Obtained on wetting mud from a pond, Capachica peninsula.

0. cf. cymatosporum Wittr. & Nordst. Obtained on wetting mud from the shore of Pun0 Bay, and from Capachica stream. Diam. of filament 7-1 1 p, vegetative cells often short, with constrictions between them. Diam. of oogonium 18-33p, subspherical or depressed spherical, single or in pairs, pore median. Mesospore finely scrobiculate. The specimens differ from the description of 0. cymatosporum in having constrictions between the cells and in the small size of the oogonium.

I

~ i ~ . 2. Oedogoniuln sp.nov. ( x 395).

0. Franklinianum Wittr. Obtained on wetting mud from the shore of Pun0 Bay. 0. globosum Nordst. A204, A205, A21 1 ponds, Capachica peninsula. 0. Howardi G. S. West. Obtained on wetting mud from ponds, Capachica peninsula. Filament 10-1 1 p

br., cells 3-4 times as long as broad, distinctly capitellate. Oogonia depressed globose with a distinct median split, c. 30p diam., oospore completely filling the oogonium.

0. inconspicuum Hirn. A211, A213 ponds, Capachica peninsula; also obtained on wetting mud from these ponds and from the shore of Pun0 Bay.

0. Landsboroughi (Hass.) Wittr. A205 pond, A213 ditch near Hacienda Chapa, Capachica peninsula. 0. lageniforme Hirn. A 205 pond, Capachica peninsula. 0. mammiferum Wittr. Obtained on wetting mud from shore of Pun0 Bay. 0. mitratum Hirn. A212 shallow drying pond, Capachica peninsula. 0. cf. multisporum H. C. Wood. A211 pond, Capachica peninsula. The specimens agree with this

species in having very short vegetative cells, oogonia in groups of 2-3 and in the dimensions, but differ in having a median pore instead of a superior one.

TUTIN-ALGAE 199

Oedogonium pisanum Wittr. Obtained on wetting mud from the shore of Pun0 Bay. 0. plagiostomum Wittr. A205, A213, A215 pond and ditch, Capachica peninsula. Some of the

specimens appear to be referable to 0. gracilius (Wittr.) Tiff. (0. plagiostomum var. gracilius Wittr.), but since the only differences between these two species mentioned by Tiffany (1937, p. 36) are in the dimensions of the cells, and there appears to be every intermediate, I have included all my material under the one name which is therefore used in a broad sense.

0. cf. psaegmatosporum Nordst. Obtained on wetting mud from the shore of Pun0 Bay. The Peruvian specimens appear to be dioecious but otherwise agree well with the description of this species.

0. cf. rugulosunt Nordst. Obtained on wetting mud from the shore of Pun0 Bay. No dwarf males seen. 0. sociale Wittr. A 205 pond, Capachica peninsula. 0. suecicum Wittr. A213 ditch, Hacienda Chapa, Capachica peninsula; also obtained on wetting mud

0. varians Wittr. & Lundell. A203 pond, Capachica peninsula. 0. cf. Zehneri (Tiff.) Tiff. Obtained on wetting mud from pond, Capachica peninsula. Oedogonium sp. A21 1 pond, Capachica peninsula. Nanandrous. Vegetative cells 6-lop br., 14-2Qp 1.

Dwarf male usually on oogonium, stalk cell 7 p br., lop l., antheridium 6 x 6p. Oogonia in groups of 2-3, depressed globose, c. 20p diam., pore median, wall of oospore smooth. Most nearly resembles 0. depessum Pringsh. from which it differs in the shorter, narrower vegetative cells, the somewhat larger dwarf male and in having the oogonia in groups of 2-3.

Oedogonium sp. P.F.H. 164 plankton, Lake Titicaca (Lago Pequefio). Cells c. Gp br., 30-35p l., chloroplasts small. Cell division occurring freely. Sterile.

Sterile specimens of Oedogonium were also found in collections from Capachica stream and on microscope slides left for three weeks in 0.5 m. on Zannichellia in moderate shelter, in 1.5 m. among totora and in 0.5 m. on a bare sandy bottom in Taman.

from Capachica stream.

7. CONJUGALES

Zygnema peliosporum Wittr. A 201 small pond, Capachica peninsula. Sterile specimens of Zygne?na were also collected from several other ponds and the Capachica stream.

Mougeotia viridis (Kutz.) Wittr. Obtained on wetting mud from a pond, Capachica peninsula. This species produced zygospores freely under laboratory conditions.

Mougeotia sp. P.F.H. 164 plankton, Lake Titicaca (Lago Pequefio); P.F.H. 84, A216, A233, A234, A 247, A266, A268 plankton, Lake Titioaca (Lago Grande). Small sterile filaments occurring sparsely at depths down to 50 m. Cells 5-6p br.

Sterile specimens of other species of Mougeotia were collected from a small lake a t San Antonio de Esquilache (alt. 4700 m.) and on microscope slides left for three weeks in 0.5-1.5 m. in Taman. Filaments were also obtained on wetting mud from a pond, Capachica peninsula.

Spirogyra cataeniformis (Hass.) Kiitz. Obtained on wetting mud from a pond, Capachica peninsula. S. injlata (Vauch.) Rabenh. A203-205, A211, A212, A215, A261a ponds, Capachica peninsula. S. Jiirgensii Kiitz. A2Q0-202, A204, A205, A212, A213, A261a ponds and ditches, Capachica penin-

sula. There is a slight doubt whether these specimens should be referred to this species or to S. decimina, but on the whole they seem to agree best with S. Jiirgensii.

S. longata (Vauch.) Czurda. A 205, A 2 1 I , A 212, A 2 15 ponds, Capachica peninsula. Rather a narrow form.

S. cf. porticalis (Mull.) Cleve. A21 1 pond, Capachica peninsula. S. sticticu Wille (Sirogonium sticticum Kiitz.). A200, A202-205, A213, A215 ponds and ditches,

Capachica peninsula; also obtained on wetting mud from ponds and Capachica stream; A209 pool behind shingle bank, Taman (sterile).

S. varians (Hass.) Kutz. A205, A211 pond, Capachica peninsula; A225 Capachica stream. S. Weberi Kutz. A204 pond, Capachica peninsula.

Sterile specimens of Spirogyra were common in most of the collections given above, and also in collections from a well among Inca ruins, Titicaca Island, a small lake near Lagunillas a t 4400 m., and a spring near Lagunilla Lagunilla a t 4300 m.

25-2


Closterium acerosum (Schrank) Ehrenb. Obtained on wetting mud from Laguna Tejane (Titicaca). Produced zygospores freely under laboratory conditions.

C. Cynthia De Not. Obtained on wetting mud from a pond, Capachica peninsula, and from Laguna Te j ane.

C . cf. Leibleinii Kutz. Obtained on wetting mud from a pond, Capachica peninsula. Euastrum sp. Obtained on wetting mud from a pond, Capachica peninsula. Staurastrum paradoxum Meyen. P.F.H. 225 plankton, Lagunilla Lagunilla.

8. SIPHONALES

Vaucheria hnmata Walz. A202, A205 ponds, Capachica peninsula; also obtained on wetting mud from

Vaucheria sp. Spring near Lagunilla Lagunilla, 4300 m. and stream near Urmiri, Pazfia, Bolivia. a pond.

9. XANTHOPHYCEAE

Botryococcus Rrnunii Kiitz. P.F.H. 225 plankton, Lagunilla Lagunilla; uncommon ; P.F.H. 232 plankton, Lagunilla Saracocha; P.F.H. 192, 193 plankton, Lake Poop6; P.F.H. 164 plankton, Lake Titicaca (Lago Pequefio); P.F.H. 84, P.F.H. 284, P.F.H. 287, A210, A219, A227, A229, A232, A234, A236, A243, A244, A251, A254 plankton, Lake Titiraca (Lago Grande). Usually very abundant.

Z'ribonema sp. Obtained on wetting mud from Capachica stream.

10. DINOPHYCEAE

Glenodinium. P.F.H. 193 plankton, Lake Poop6. Peridinium. P.F.H. 225 plankton, Lagunilla Lagunilla ; P.P.H. 232 plankton, Lagunilla Srtracocha ;

P.F.H. 164 plankton, Lake Titicaca (Lago Pequeiio); P.F.H. 84, A219, A227, A233, A234, A236-239, A244, A 246-251, A254, A255, A266-268 plankton, Lake Titicaca (Lago Grande). Never abundant but occurring in most collections, particularly the deeper ones made with the Harvey net.

1 1. CYANOPHYCEAE

Microcystisfirma (Breb. & Lenorm.) Rabenh. A242 small lake, San Antonio de Esquilache (4700 m.). Chroococcus Zimneticus Lemm. var. distans G.M.Sm. Y.P.H. 225 plankton, Lagunilla Lagunilla. Rhabdoderma salina sp.nov. P.F.H. 192, 193 plankton, Lake Poop6.

Cellulae 3 p longae, 1 p latae, in medio aliquanto flexae. Coloniae parvae paucicellulatae, mucilagine fere transparente. A Rh. minima cellulis latioribus minus flexis differt.

Cells 3 p l., l p br., somewhat bent in the middle. Colonies small, few celled, mucilage nearly transparent. Most nearly resembles Rh. minima from which it differs in having the cells broader in proportion to their length and only slightly bent.

Marssoniella andicola sp.nov. P.F.H. 225 plankton, Lagunilla Lagunilla. One of the commonest plankton algae in this lake.

Cellulae 9-10 p longae, 3-4p latae, anguste piriformes, terminis acutis ad medium coloniae directis. Coloniae paucicellulatae, cellulis radiantibus. A M . elegante dimensionibus cellularum et terminis acutis ad medium coloniae directis differt.

Cells 9-lop l., 3-4p br., narrowly piriform with the pointed ends towards the middle of the colony. Colonies few celled, cells radially arranged. Differs from M . elegans Lemm., the only other species, in the dimensions of the cells and in having the pointed ends of the cells towards the middle of the colony.

Pleurocapsa minor Hansg. em. Geitler. Obtained on wetting mud from a pond, Capachica peninsula. Rivularia sp. Obtained on wetting mud from a pond, Capachica peninsula. Tolypothrix distorta Kutz. A241 small lake, San Antonio de Esquilache (alt. 4700 m.). hlodularia spumigena Mertens. A 263, pools in rocks in a stream running into Urufii Bay; small lake at

4400 m. near Lagunillas; A220, A221 Capachica stream; A200, A204, A205, A211 ponds, Capa- chica peninsula: also obtained on wetting mud from a pond and from the shore of Pun0 Bay.

TUTIN-ALGAE 201

Nodularia Harveyana Thur. A216, A219, A232, A234, A238, A239, A246, A250, A266, A267 plankton, Lake Titicaca (Lago Grande) ; fairly frequent but never abundant down to 50 m. ; also obtained on wetting mud from the shore of Pun0 Bay.

Nostoc Linkia (Roth.) Bornet. A204 pond, Capachica peninsula; A220 Capachica stream, near the mouth; A258 Taman, on boulders in about 0.5 m.

N . piscinale Kiitz. A210 pond, Capachica peninsula. N . sphaericum Vauch. A208, A258 Taman, on sides of boulders; A217 Taman, on moss (Sciaromium)

down to about 14 m.; A210 pond, Capachica peninsula; also obtained on wetting mud from this pond. Common on boulders, as an epiphyte on Potamogeton and other plants in sheltered places, and on Sciaromium a t the lower limit of vegetation.

Anabaena catenula (Kutz.) Bornet & Flah. A263 stream running into Urufii Bay; in pools among rocks.

A . cylindrica Lemmerm. A220 Capachica stream, near the mouth. Another unidentifiable species of Anabaena was also collected in this stream.

Anabaenopsis peruviana sp.nov. Obtained on wetting mud from a pond, Capachica peninsula, and from Laguna Tejane, Lake Titicaca.

Trichomata spiralia plerumque cum anfractis duobus, nonnulla inter se convoluta vaginis nullis. Cellulae cylindricae, septis distincte constrictae, pseudovacuolis nullis, 4-5 p latae, 6-7 p longae. Heterocystae ad terminos utrosque filamentorum positae, nunquam intercalares, ellipsoideae, 6 p latae, 9-1011 longae.

Trichomes spiral, mostly with two turns, several coiled together, sheaths absent. Cells cylindrical, distinctly constricted a t the cross walls, without pseudo-vacuoles, 4-5p br., 6-7 p 1. Heterocysts a t both ends of the filaments, never intercalary, ellipsoidal, Gp br., 9-lop 1. This species appears to resemble A . Tanganyikae (G. S . West) Wolosz. most nearly but differs from it in being larger ( A . Tanganyikae: cells 2 - 6 2 . 6 p br., 3 . 8 - 8 . 5 ~ l., heterocysts 3 x 5 . 5 ~ ) ~ having the cells shorter in proportion to their breadth, and distinctly constricted a t the cross walls.

Cylindrospermum Titicacae sp.nov. (Fig. 3). Obtained on wetting mud from the shore of Pun0 Bay. Trichomata solitaria, recta, brevia, natantia. Cellulae septis

valde constrictae, 3.0-3.5 p latae, sesquilongae usque ad duplo longiores quam latae. Heterocystae ellipsoideae, sporam versus in projcctionem brevem obtusam constrictae, 4p latae, 6 p longae. Sporae solitariae, leves, contcntis granulatis, cylindricae, c. 5 p latae, 10-12 p longae. Sporae veteriores, a trichomate segregatae, ala mucilaginosa quam spora semilata instructae.

Trichomes solitary, straight, short, free-floating. Cells strongly constricted at the cross walls, 3 . 0 - 3 . 5 ~ br., once and a half to twice as long as broad. Heterocysts ellipsoidal with a short blunt point at the attachment to the spore, 4p br., Gp 1. Spores solitary, wall smooth, contents granular, cylindrical, c. 5 p br., 10-12p 1. Older spores, detached from the trichome, develop a wing of mucilage about half the width of the spore. Differs from C. minimum G. S. West, described from the Central Andes (alt. 2300 m.), in the larger size of the cells and the marked constrictions between them.

Fig. 3. Cylindrospermum, Titicacae sp.nov.

A, filament; R, detached spore.

Spirulina Jenneri (Stizenb.) Geitl. A214 pond, Capachica peninsula. S. laxa G. M. Smith. Obtained on wetting mud from Chapa pond, Capachica peninsula. S. laxissima G. S . West. A222 Capachica stream. S. subtilissima Kutz. A22 1 Capachica stream.

An unidentified species of Spirulina was also obtained on wetting mud from the shore of Pun0 Bay.

Oscillatoria ornata Kiitz. Obtained on wetting mud from a pond, Capachica peninsula. A species of Oscillatoria was also found in a plankton collection from Lagunilla Lagunilla

Lyngbya aestuarii (Mert.) Liebmann. P.F.H. 192, P.F.H. 193 plankton, Lake Poop6, in brackish

L. Martensiana (Kutz.) Gom. A242 small lake in crater, San Antonio de Esquilache (alt. 4700 m.).

(P.F.H. 225).

water.


Microcoleus granulatus sp.nov. A202 pond, Capachica peninsula. Filamenta numerosa, haud ramosa, in fasciculos c. 7 0 p latos dense glomerata. Vagina scabrida

c. 15 p crassa. Filamenta apicem versus paulo angustata, cellula ultima rotundata. Cellulae 5 p latae, 6-8p longae, septis granulatae, haud constrictae.

Sheath rough, c. 15p thick. Filaments slightly narrowed towards the apex, end cell rounded. Cells 5 p br., 6-8p l., granulate a t the cross walls, not constricted. Differs from M . Lauterbachii Schmidle in having the cross walls granulate, the cells only slightly longer than broad, the trichomes very numerous in each bundle and the sheath rough.

Circumstances have made it impossible to obtain the specific names of the Dino- phyceae collected by the Expedition. The Diatoms will be described in a separate paper by Mr R. Ross. The list of Desmids is incomplete; the collection is in the hands of Dr M. Rosenberg. My thanks are due to Prof. P. E. Fritsch for help in identifying the species of Oedogonium.

Numerous unbranched filaments densely crowded in bundles c. 7 0 p br.

V. SUMMARY

The lakes investigated show a great variation in the concentration of dissolved salts, the chloride content ranging from 37 to 5000 parts per million. Nutrient salts are present in Titicaca in about the amounts usually found in fairly rich temperate lakes, and silica is always abundant.

The phytoplankton of Titicaca is of the type usually associated with waters poor in nutrient salts. Contrary to what has been found in most lakes, the number of species in the plankton of the Andean lakes examined (with the exception of Lake Poop6) decreases with decrease in the concentration of dissolved salts. One species of Desmid occurs in the plankton and that is found only in the lakes with a high concentration of dissolved salts. It is suggested that something other than nitrate and phosphate may be the factor controlling the distribution of these plants.

The density of the plankton population in Lake Titicaca is very low compared with North American lakes.

A list of all the algae collected in an identifiable condition is given and this includes descriptions of seven species which do not appear to have been previously described.

VI. REFERENCES BIRGE, E. A. and JUDAY, C. 1922. “The inland lakes of Wisconsin. The plankton: I. Its quantity and

HARVEY, H. W. 1934. ‘(Measurement of phytoplankton population.’’ J . Mar. Biol. Ass. XIX, 761.

PEARSALL, W. H. 1921. “The development of vegetation in the English Lakes.” Proc. Roy. SOC. B,

TIFFANY, L. H. 1037. “Oedogoniales” in North American Flora, XI, pt. 1 . (New York Botanical

chemical composition.” Wisconsin Geol. Nat. Hist. Surv. Bull. no. 64.

__ 1939. ‘(Substances controlling the growth of a diatom.” J . Mar. Biol. Ass. XXIII, 499.

XCII, 259.

Garden.)

tutin. 1940. the algae

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