Croton lasiopyrus Baill.

Kainulainen, Kent, Ee, Benjamin van, Antilahimena, Patrice, Razafindraibe, Hanta & Berry, Paul E., 2016, New species and species reports of Croton L. (Euphorbiaceae) from the eastern forest corridor of Madagascar, Candollea 71 (2), pp. 327-356 : 350-354

Croton lasiopyrus Baill. in Bull. Mens. Soc. Linn. Paris 2: 926. 1890 ( Fig. 1C , 14 ).

Lectotypus (designated here): MADAGASCAR: “Central Madagascar” , X.1882, Baron 1951 ( P [ P00133406 ]!; isolecto-: K [ K001040378 ]!, P [ P00133407 ]!). Syntypi: MADAGASCAR: “Central Madagascar” , X.1882, Baron 2114 ( K [ K001040377 ]!, P [ P00133408 ]!); “Central Madagascar” , s.d., Baron 4078 ( K [ K001040376 ]!); Fort Dauphin, s.d., Scott-Elliot 1557 ( P [ P00133052 packet in upper right]!) .

Shrubs 1-4 m tall. Branches with fuzzy reddish-brown indument. Young shoots, petioles, and inflorescence axes hirsute, with densely ferrugineous-fasciculate trichomes, with copious red sap emerging when young stems are cut. Bark on older stems conspicuously longitudinally striate with whitish fissures on smooth grayish brown background, branching di- or trichotomous. Stipules minute, often hidden by pubescence. Leaves alternate to mostly opposite or ternate, the emerging ones usually whitish from the dense indument and anisophyllous (one of the pair or trio much smaller than the others). Petioles 0.8-2.0 cm long, with two subsessile to shortly stipitate discoid glands c. 1 mm diam. at the apex or just beneath the leaf blade. Leaf blades (broadly) elliptic to obovate, 4-15 × 2.5-8 cm, apex rounded to acutely acuminate, rounded to truncate at base, margin entire or somewhat serrate in distal half, firmly chartaceous, upper surface stellate-pubescent (densely so when young but becoming glabrescent with age except for pubescent midvein), softly and densely pubescent on lower surface, dark green above, only slightly paler on lower surface, brochidodromous, with 5-7 pairs of secondary veins. Inflorescences shortly racemose, terminal or axillary, epedunculate, 1.0- 3.5 cm long, few-flowered, bisexual or all staminate, when bisexual with shortly-pedicellate pistillate flowers close to the node, the pedicel 2-3 mm long, the staminate flowers with divergent pedicels 2-6 mm long. Staminate flowers with densely stellate-hirsute, globose buds; sepals 5, lanceolate, 3.0 × 1.5 mm, abaxially stellate-pubescent; petals 5, oblong, obtuse, 2 × 1 mm, sericeous on both surfaces and margins, white; glands 5, discoid, c. 0.5 mm diam.; stamens c. 15, filaments 1-2 mm long, basally pilose, anthers 0.6-0.8 mm long; receptacle villous. Pistillate flowers: sepals 5, lanceolate, 6.0-7.0 × 1.5-2 mm, abaxially densely stellate; petals lacking or subulate and c. 1 mm long; ovary globose, c. 5 mm diam., densely stellatehirsute; styles short, stellate-lepidote (branching pattern not discernible with available material). Capsules depressed globose, densely ferrugineous-hirsute, c. 10 × 8 mm; columella 7-8 mm long, cornute and fimbriate at apex. Seeds oblong-ellipsoid, c. 6.5 × 3.5 mm, smooth, dark brown; caruncle c. 0.5 × 0.5 mm.

Etymology. – The specific epithet alludes to the woolly fruit of this species.

Phenology. – Based on the few known collections, Croton lasiopyrus does not appear to be a prolific flowerer. There are remains of staminate flowers, as well as a fruit and a dehisced capsule, from August, with additional flowering collections in April, August, November, and December.

Distribution, habitat and ecology. – Croton lasiopyrus grows in ravines and the understory of montane moist forests on the eastern side of Madagascar, in Antananarivo and Toamasina Prov., at altitudes of 900-1200 m. ( Fig. 1C ).

Notes. – Key distinguishing characters of C. lasiopyrus include the rusty, woolly pubescence on the stems and leaves, the short-petiolate, elliptic to ovate, acuminate-tipped leaves, the new leaves tightly clustered at a node and often anisophyllous (of different sizes in the same pair or cluster), and the short inflorescences that appear axillary in the leaf clusters ( Fig. 14 ). The syntype Scott-Elliot 1557 is not this species at all, but rather C. cassinoides Lam. , from the Fort Dauphin area of Toliara Prov. There is another Scott-Elliot specimen from Fort Dauphin that is close to, but probably not conspecific with, C. lasiopyrus , namely Scott-Elliot 2699 (K, P), so there may have been a mix-up in the numbers cited by BAILLON (1890).

Two collections (van Ee et al. 2215 and 2216) from the forest north of Route Nationale 2 between Andasibe and Ambatovy share many characters with C. lasiopyrus (18°54’57”S 48°20’43”E, 978 m, 14.VIII.2015, MICH, MO, P, TAN), but they were growing in close proximity to denser populations of C. enigmaticus , and we suspect they may be the result of introgression with that species. This is evidenced by noticeably serrate and acuminate-tipped leaves, more stipitate petiolar glands, and somewhat larger inflorescences and longer pistillate pedicels.

Additional specimens examined. – MADAGASCAR. Prov. Antananarivo: Analamanga Region. La Mandraka , 7.II.1937, Herb. Jard. Bot. Tan. 2380 ( P); ibid. loc., 7.XII.1959, Schlieben 8140 ( G, K); ibid. loc., 8.X.1961, Service Forestier 20332 ( G, K, MO, P). Prov. Toamasina: Alaotra-Mangoro Region, [Ambatondrazaka Distr.], forêt d’Ambodipaiso , près d’Antsevabe , 1200 m, 12.I.1945, Cours 2293 ( K, MO, P); Anony, forêt du N aux confins du pays Sihanaka , [17°13’S 48°32’E], 3.IX.1937, Herb. Jard.Bot.Tan. 2957 ( P); Moramanga Distr., Ambohibolakely, Corridor Forestier Analamay Mantadia , forêt d’Amboasary , 1019 m, 25.IV.2012, 18°47’11”S 48°23’00”E, Rakotovao 5812 ( MO, P, TAN); Lakato, forest E of Manasamena village, along the Ankandrabe trail , 1062-1100 m, 2.VI.2007, Randrianasolo et al. 1148 ( MO, P, TAN); along road to Lakato , 1080 m, 19°03’10”S 48°22’20”E, 11.XI.2003, Schatz et al. 4186 ( MO, P); ibid. loc., 1022 m, 19°02’47”S 48°21’25”E, 27.II.2009, van Ee et al. 978 ( MICH, MO, P, TAN); ibid. loc., 1022-1038 m, 19°02’52”S 48°21’24”E, 13.VIII.2015, van Ee et al. 2197 ( MICH, MO, P, TAN); ibid. loc., van Ee et al. 2204 ( MICH, MO, P, TAN).

Figures

Fig. 1. – Distribution maps. The grey squares or white arrow on the inset maps of Madagascar show the location of the area depicted. A. Croton ferricretus Kainul., B.W. van Ee & P.E. Berry (red); B. Distribution of Croton droguetioides Kainul. & Radcl.-Sm. (turquoise) (Cours 4111 not shown), C. enigmaticus P.E. Berry & B.W. van Ee (light green) (Ralimanana et al. 1402 not shown), C. indrisilvae Kainul., B.W. van Ee & P.E. Berry (yellow), and C. plurispicatus P.E. Berry, Kainul. & B.W. van Ee (light purple); C. Croton ankeranae Kainul. (yellow), C. radiatus P.E. Berry & Kainul. (red), and Croton lasiopyrus Baill. (white). The collection in gray represents presumed hybrids between C. lasiopyrus and C. enigmaticus (van Ee et al. 2215 and 2216); D. Croton hypochalibaeus Baill. in Madagascar. [Google Earth Image © 2016 DigitalGlobe.Reproduced per attribution guidelines]

Fig. 14. – Croton lasiopyrus Baill. A. Habit, with patent leaves; B. Cross-section of woody stem (diam. c. 4 cm), showing reddish sap at cambial layer; C. Young twig cut to show the reddish sap that is exuded; D. Leaves.Note the atypical serrate leaf margin of this specimen (van Ee et al. 2215), which may be introgressed with C. enigmaticus; E. Shoot apex with anisophyllous leaves; F. Close up of shoot showing the reddish, wooly pubescence. Note the acropetiolar gland at the lower side of the blade; G. Inflorescence with old staminate flowers and bud. Note the divergent pedicels; H. Pistillate flower; I. A nearly mature capsule and the remaining calyx and columella of an already dehisced capsule. [A, C-E, G, I: van Ee et al. 2197; B, F: van Ee et al. 978; H: van Ee et al. 2215] [Photos: A, C-E, G-I: P. Berry; B, F: B. van Ee]