KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. NIO 5. 



113 



parts the plant presents an obvious similarity to P. polygonus, whereas spikes and 

 pistils bear closer resemblance to P. Aschersonii. In several respects it is intermc- 

 diate between the two. 



The stem is little branched beneath the primary spike. From this it shoots 

 out like P. Aschersonii. In shape it is a little compressed. The anatomic diagram 

 shows an epidermis with a one-celled pseudo-hypoderma and scattered, very strong, 

 subepidermal strands, but no interlacunar ones. The central cylinder has an oval 

 crosscut-form with the lateral bundles separated from the median ones (oblong 

 diagram). 



Peduncle somewhat compressed; its vascular bundles being 4 in number rim 

 near together. Hypoderma and subepi- 

 dermal strands as in P. Aschersonii. 



The stem-leaves remind much of a 

 polygonus-leaå, but are only 50 — 60 mm 

 long by 2 mm broad. The marginal 

 strand is very strong consisting of 50 

 bast-cells or more. For the rest I refer 

 to the figure. The ligules are 6 — 7- 

 fibrous in the front-field and decay in 

 the same way as in P. polygonus by 

 leaving a whorl of nerves at the base. 



As to form and size the leaves 

 nearly correspond with those of P. orien- 

 talis, which, however, has much softer 

 leaves on account of a less developed 

 sclerenchymatous tissue. 



Distribution. Brazil: Säo Paulo. 

 Campinas, 1868, S. Henschen (hb. Stock- 

 holm, et Uppsal.). I have seen a spe- 

 cimen from »S:a Catharina, Gråben am 



Itajahy unterhalb Blumenau, 1886, H. Schenk» (hb. Berolin.), which is likely to be 

 this hybrid. — The main-form now described could be named: a strictus. 



Another form of this hybrid is found at Amparo, Prov. S:t Paulo, of Brazil. 

 It has short internodes, thence more polygonusAWie. Stem-leaves 80 — 90 X 2 mm, 

 3-nerved (P. Aschers.), apex rather intermediate in shape, base always tapered; la- 

 cunar part not occupying the whole space between the midnerve and the chief lateral 

 one. Ligules open, 10 — 11-nerved in the front-field (P. polyg.), with rounded tip, 

 10 mm in young state; on decaying they leave an annulus round the stem (P. po- 

 lyg.). Peduncle 25 mm in length. Spike 4 — 5-verticillate. This form I will name: 



[3 polygoniformis. — Caulis internodiis brevissimis (± 10 mm). Folia quoad for- 

 mam et structuram intermedia. — The specimen examined is preserved in Hb. Univ. 

 of Copenhagen. Coll. »Lindberg, in 1854», acc. to the label of Baagöe. 



K. Sv. Vet. Akad. Handl. Band 55. N:o 5. 15 



Fig. 48. P. attenualus Haostr. A, Base (a) and top {b) of a 

 stem-leaf showing the form and norvation. The primary side- 

 nerves join the midvein in the very top as in P. polygonus, \ 

 B, Cross-section of a stem-leaf at the middle, midrib-portion (>») 

 and margin (str), ca. 7 ,°. C, Pistil, a, side-view, b, inside view, c, 

 stigma from above, \- . I), Cross-section of peduncle. The four 

 vascular bundles (vb), subepidermal strands (str), 3 1 5 . 



