Ixora acuminata

Roxb. Hort. Beng. 10 ; Fl. Ind. i. 383 ; glabrous, leaves petioled elliptic or linear-oblong acuminate coriaceous, floral pair obovate or oblanceolate from a sessile auricled or rounded base, cymes sessile or subsessile corymbiform contracted dense-flowered, bracteoles elongate subulate, calyx glabrous teeth lanceolate much longer than the ovary, corolla-tube very slender 1-1.1/4 in., lobes narrowly obovate, mouth pubescent or villous. DC. Prodr. iv. 488 ; Wight Ic. t. 706 (not good) ; Wall. Cat. 6126.

Sikkim Himalaya, alt. 3000 ft., C. B. Clarke ; Bhotan, Griffith ; Assam, Khasia Mts., ascending to 4000 ft., and Cachar, Hamilton, &c. ; Chittagong, C. B. Clarke.

A robust glabrous shrub ; branches smooth. Leaves very variable, floral sometimes only 1/2 in., rounded or linear-oblong, in extreme forms 12 by 6 in. with a cordate base ; other leaves 5-9 by 1.1/2 to 3 in., narrowed into a very short petiole 1/3-1/2 in., pale when dry, very coriaceous ; nerves 15-20 pair, slender, arching ; stipules broad with very short points. Cymes 2-4 in. diam., sometimes almost capitate, quite glabrous ; flowers white, sweet-scented, sometimes 5-merous ; bracts and bracteoles long, filiform. Calyx 1/4-1/3 in. Corolla 2/3 in. across the narrow obtuse lobes. Anthers sessile. Stigma fusi¬form or 2-fid, with short arms. Fruit 1/4-3/4 in. long, ellipsoid or oblong, straight or oblique, crowned with the slender calyx-teeth.—The extreme forms are the Sikkim, with 5-merous flowers and very small orbicular floral leaves ; and Upper Assam ones, with these sometimes 20 in. long and 7 broad. Griffith’s Bhotan specimens (Kew Distrib. 2983) have calyx-teeth sometimes hardly longer than the tube.

(Attributions: IBIS Flora (FBI))
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ID No.13062011 RD_New 2:
Resending again for ID. Could it be any Clerodendron sp?

Ixora sp. of Rubiaceae family.

Going by the keys at Rubiaceae – Ixora sp. for ID  and POWO specimen, I think it is closer to Ixora acuminata Roxb.

References:
POWO specimen  GBIF (High resolution specimens) BSI Flora of India  India Biodiversity Portal  IBIS Flora (FBI)