SAXIFRAGACEAE 

 Hydrangea indochinensis sp. nov. § Euhydrangea, Petalanthae. 



Frutex, intlorescentiis exceptis glaber vel subglaber; ramis teretibus, 

 glabris, laevibus, in sicco subatro-viridibus, junioribus brunneis, ultimis 

 circiter 1 mm. diametro; foliis lanceolatis vel oblongo-lanceolatis, 7-11 cm. 

 longis, 2-i cm. latis, graciliter acuminatis, basi acutis vel cuneatis, sub- 

 membranaceis. in sicco supra olivaceis, subtus pallidioribus, utrinque glabris 

 vel junioribus subtus obscure conspersissime breviter pubescentibus, mar- 

 gine plerumque revolutis, obscure subcalloso-denticulatis vel deorsum in- 

 tegris, dentibus minutis, 1-3 mm. distantibus; nervis primariis utrinque 

 circiter 7, gracilibus, distinctis, curvato-adscendentibus, circiter ad mar- 

 ginem obscure arcuato-anastomosantibus; petiolo glabro, 1-2 cm. longo; 

 inflorescentiis terminalibus, pedunculatis, breviter, subadpresse substrigoso- 

 hirsutis, pedunculo circiter 4 cm. longo, ramis primariis pedunculum sub- 

 aequantibus, subpatulis, sub fructu (sine radiis sterilibus) ad 9 cm. latis, 

 pedicellis 3-5 mm. longis; capsulis ovoideis, circiter 4 mm. longis, additis 

 stylis persistentibus 3-S (plerumque 4) 2-2.5 mm. longis, extus leviter 

 8-costatis, subrefractis, glabris vel praesertim deorsum conspersissime sub- 

 adpresse hirsutis, in vivo ut videtur subazureis; calycis lobis persistentibus 

 5, oblongis, obtusis, suberectis, 0.5 mm. longis; ovario sub fructu plane 

 infero vel apici leviter protruso; seminibus pallidis, oblongo-ellipsoideis, 

 utrinque subattenuatis, utrinque subacutis vel apice subacuminatis, vix vel 

 obscure alatis, longitudinaliter striatis, circiter 1 mm. longis; radiis sterili- 

 bus circiter 5, elongatis, ad S cm. longis sub medio saepe flores 1-3 fertiles 

 ferentibus; floribus sterilibus sub fructu 4-meris, albidis, circiter 4 cm. 

 diametro, sepalis suborbiculari-ovatis vel suborbiculari-obovatis, integris, 

 168 Az**^- JOURNAL OF THE ARNOLD ARBORETUM [vol. xxm - /f^^ 



rotundatis, basi late acutis, chartaceis vel submembranaceis, 1.5-2 cm. 

 longis, 1.2-1.8 cm. latis, subperspicue longitudinaliter 7-costatis, reticulatis, 

 utrinque, praesertim deorsum, secus nervos conspersissime breviter hirsutis. 



In-do-Chixa, Tonkin, Chapa, Massif de Fan Tsi Pan, Pételot 2687, July 1940, in 

 humid ravines, ait. 2200 m. 



This is the second species of the genus to be recorded from Indo-China. 

 It is characterized by its thin leaves, by being entirely glabrous except the 

 inflorescences, by its inferior ovaries, apparently somewhat nodding cap- 

 sules, and greatly elongated stérile rays, each bearing a single stérile flower, 

 and about half way along the peduncle 1 to 3 fertile flowers. In spite of its 

 distinctly superior ovaries, it clearly belongs in the group with Hydrangea 

 chinensis Maxim., and its closest described ally may be Hydrangea kwang- 

 siensis Hu, Jour, .\rnold .\rb. 12: 152. 1931, le. PI. Sin. 3: 35. t. 135. 1933. 



