Arkiv för botanik

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o i stria in 10 1 frequently misSin unitateralty oni pacenea tho centrum and irregulari dilate Mon the opposito fide. Axia striae sinooth or interrupteli in tho mi lillo Marginalestriae S in 10 p. composed os circular punctu. Hypothoen with 10 11 inely unctate Striae, vanishing oward tho

centrum.

that I avo distinguishod tho species by oK, though the

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The specimen, rawn in fig. 51 agroes et with LEVE 'AAchnanthes pennata in sige and ulline Oni it has disti nollypunctato striae, the puncta tormin Strnight transversa aswellis longitudina rows, 10 in I 0 1, hereas LEVE 'A figurelias eon delinoated illi sinooth striae A tho Synopsis II, p. 94 does no teli anythin abolit the natur of thostrino the idontification o m forin illi Achn pennata isno perfecti certain. It is however, probabio that ali triae fornis of Achnanthes brevipes have punctate triae, thia at Soth latior varie ty. Achnanthes arctica CL. Achnanthidium arcticum L. P. P. D. Aret Seu P. 25 Tub. 4 f. 22 not in Achnanthes reripes Ag. var intermedia K0 TZ CLEVE, Syn NaV. D. II, p. 93

row of eoarse, subquadrates, distant alveoli in 10 1 in ea chro 5 alveoli in 10 3. Alveoli formin som0What undula linglongitudina rows. Axia area distinc or not. Lower alvo with ather distant median ore an a linear Xin aren, dilato in the idcllo to a somowhatiroad tranSVerSe a Seiaan nea the onds to mali rounded areas. Striae subradiate, in I is , coarSel punctate. Planeta quadrate formin regula longitudinal OUS. Tho frustulo has do ubi membranos the inner ne ut Some distanc fro the ther on the dorsa sicle and withan Reuto Orner eaning against the transverse nil of the

conneoting one of the uter membrano.

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Achnanthe septata, Sine the valve, drawn by LEVE in fig. 22 b D. Arct Soa, Tab. ), elong to the alter species. Both of tho specios in question occurring ather abundantly in the ni Asha-Samples, I have been able to comparo themolosel in valva view, an state thoi differetico, hich maybe Seen hon comparing the figures 55-57 of this aper. Later on, LEVE has uni ted Achn arcti a illi Achnanthes subsessilis Κ0ΤZ. in hicli I cannot agro with him. Thoso formes are certaint quit different in generat Structure, habitually, and in Alge. The numbers of 30-50 p. for the tengthan 10 11 1 for the readth given in LEVE 's Synopsis for Achnanthes brevipes var intermedia, appl to tho truo Ach-nanthes ubsessilis, ut noto tho considerabi large Ach-nanthes arctica, or hicli CLEu himself in his original 0-

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yroentandica an Achii arctica in Also tho diaphragnis of Acmι. yroentandica Seemo bo uel les markod than in tho present species, no bella visibi at ali on LEVE ' figures D. Arol. ea, Tab. 4 f. 23 Vega-EXP. D. Tab. 35 f. 3j. In OsTRUP' figure of Achnanthes strOentandica L. Var. v KySt i. Groni Tab. 2 f. t the are represented. inalty tho distincti quadrate puncta re coarser in Achn septata, forwhicli reason the Aeem es distant though there is almost the fame number of striae in I in in both species. Fro Achnanthes arctica his species is distinguishod by the presene os diaphragm S, by the narro fascia by thelao of an axia area an by the coarser alveoli. The SiZeis bout the Same .

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Distr. Ires iv. in ubiquist frequent in id deposit ironi

Distr. mar an brach. in Aretis, AntaretiS, ubi quis t. Surirella fossilis D. Sp. - l. 3 f. l. ΦValvo sopolar, elliptical illi subacute en df, 56 p. in longili 36 re in readth. Wings marginal, mahing one oldin Q in producin depreSSion o the valve, visibi on alithe pace et veen the margin and the rapho that is aintly mari sed . Striation fine. Melicate, Nisibi ali ver the valve.

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Whole marginal par of the valvo oontinue each by two O three clos costa line to tho narro lanceolate-fusi formcentra area.

Foss. Sat Panelia, raro Litorina- leposit). There is a resemblance etwoen his delicato Surirella belongin to tho tribe of the fa8tuosae, an a more roundedobtuse form recenti describe in Contrib. Diat. Venegia 191 3 by M A FORΤ1 and ameti Surirella triatida TURP. Var Azpeiticae, rom a seposit in Modena Tab. 9, . . Some allie form aro figure in . . Att. Tab. 5 f. 12 as Surirella faεtuoεα var. At l. Tab. 24 f. 28 as Surirella recedens A. . and speciali in the Atl Tab. 299, t. 32 as S. eptentrionalis IIUST.

Campylo discus HB. campylo discus angularis GREG. - . o Clyde, Tab. 3,