110 



J. O. HAGSTROM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



The stem is flattened in the relation of about 2,3 : 1. Its endodcrmis has a 

 pseudo-hypoderma with the usual subepidermal strands. The central cylinder pre- 

 sents the comraon oblong diagram. In the peduncle, being 

 2,5 — 5,fi cm in length, the four vascular bundles run separated 

 by distinct interspaces. The hvpoderma and the subepidermal 

 strands we refind, as in the stem, though the latter are a 

 little reduced in number and strength. The leaves have a 

 more or less rounded base and a more or less tapered and 

 cuspidate apex. The proper stem-leaves are 5-nerved, the 

 branch-leaves usually 3-nerved. The former resemble very 

 much a )nucronaius-\eaf, but the midrib is on either side accom- 

 panied by 3 rows of lacunac in its basal half with mechanical 

 strands running subepidermally. The ligules are convolute and 

 exhibit 8 — 11 strands in the front-field. The style is short, 

 stigma rounded or oval, broad and expanded (see the fig. 45, C !). 

 Distribution. Brazil: S. Paulo, Santos, 74, Mosén (hb. 

 Stockholm., Uppsal., Lund.), »A. 821 j, Lindman (hb. Stock- 

 holm.). — The plant from S. Paulo, Amparo, Lindberg, (hb. 

 Stockholm.), with shorter (6—20 mm) internodes seems to be a 

 hybrid (see p. 113). 



P. Berteroaims PiiiLirn. 



-CO, 



Plantarum novarum Chilensium etc. in Liniuva 1859- 

 200. — Fig. 46. 



The discoverer of this plant has confounded it with 

 the species afterwards named P. Aschersonii. I have in fact 

 scen specimens from the very locus classicus, Tagua-Tagua, de- 

 termined by Phileppi himself. They are not P. Berteroanus, 

 but P. Aschersonii. The two species have of course grown 

 together, but the author has made his description according to 

 the broader-leaved form, since he writes, > foliis — — — 5-ner- 

 viis», whereas P. Aschersonii has, at least in general, 3-nerved 

 and narrower (1,5—2 mm) leaves. 



Stem distinctly compressed (2,5:1) and anatomically built 

 c, Pietii, «, U p according to the usual type of the group witli a one-celled 



side-view, '<, dorasJ view, <■, x " * *■ ** 



i rron »bovo, ',-'■ i>, or at the edges 2-cclled pseudo-hypoderma and a full number 



of ;i ligale al r . . , , , /-i . i i- j r ii ii t 



•i,, bue ibowing the form <.f ol subepidermal strands. ( entral cylinder oi the oblong uia- 

 ;;; , V;i:; , ;'; l ' , ;;, u !: Ku1 '' v gram type. Peduncle almost terete with BCattered subepi- 

 dermal strands in the one-celled hypoderma. Yascular bundles 

 four, the median running together, the lateral oncs more distantly from the centre. 

 Leaves 5— 7-nerved. On either side of the midrib there are threc (in the stem- 

 leaves) or 2 (branch-leaves) rows of Lacunse. For t lie nervation 1 refer to the fig. 



Fig. 45. /'. Gayii Hinn. 

 .1, Ti ans* ion of ped- 



uncle showing thi' course of 



thl \as,ular- and liast-bun- 



■ II' s, ",". /;, Transi , i .. section 

 ol a stom-leaf belort the middle 

 ihowing tic lacnnar system of 

 ili' midrib and its strands [ttr) 

 iho disposition oi tlu \ asonlar 

 bandit */■ »' >• and the mar- 



